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Sample records for voltage-controlled oscillator vco

  1. A 3.01-3.82 GHz CMOS LC voltage-controlled oscillator with 6.29% VCO-gain variation for WLAN applications

    Science.gov (United States)

    Xiaolong, Liu; Lei, Zhang; Li, Zhang; Yan, Wang; Zhiping, Yu

    2014-07-01

    A wideband low-phase-noise LC voltage-controlled oscillator (VCO) with low VCO gain (KVCO) variation for WLAN fractional-N frequency synthesizer application is proposed and designed on a 0.13-μm CMOS process. In order to achieve a low KVCO variation, an extra switched varactor array was added to the LC tank with the conventional switched capacitor array. Based on the proposed switched varactor array compensation technique, the measured KVCO is 43 MHz/V with only 6.29% variation across the entire tuning range. The proposed VCO provides a tuning range of 23.7% from 3.01 to 3.82 GHz, while consuming 9 mA of quiescent current from a 2.3 V supply. The VCO shows a low phase noise of -121.94 dBc/Hz at 1 MHz offset, from the 3.6 GHz carrier.

  2. A Compact Ka-Band PHEMT MMIC Voltage Controlled Oscillator%紧凑型Ka波段PHEMT微波单片集成VCO

    Institute of Scientific and Technical Information of China (English)

    余稳; 孙晓玮; 钱蓉; 张义门

    2005-01-01

    设计并流片制作了基于GaAs PHEMT工艺的Ka波段微波单片集成压控振荡器(MMIC VCO).该VCO具有紧凑、宽电调谐带宽及高输出功率的特点.提出了缩小芯片面积及增大调谐带宽的方法,同时还给出了设计MMIC VCO的基本步骤.该方法设计并流片制做的MMIC VCO的测量结果为:振荡频率为36±1.2GHz,输出功率为10士1dBm,芯片面积为1.3mm×1.0mm.%A compact Ka-band monolithic microwave integrated circuit(MMIC) voltage controlled oscillator (VCO)with wide tuning range and high output power, which is based on GaAs PHEMT process,is presented. A method is introduced to reduce the chip size and to increase the bandwidth of operation. The procedure to design a MMIC VCO is also described here. The measured oscillating frequency of the MMIC VCO is 36±1.2GHz and the output power is 10±1dBm. The fabricated MMIC chip size is 1.3mm× 1.0mm.

  3. 24 GHz Low Phase Noise MMIC Voltage Controlled Oscillator%24 GHz低相位噪声单片集成VCO

    Institute of Scientific and Technical Information of China (English)

    谭超

    2013-01-01

    The 24 GHz MMIC voltage controlled oscillator (VCO)based on the GaAs heterojunction bipolar transistor (GaAs HBT) technology was introduced.The MMIC VCO integrated 1/2 harmonic output and divided-by-8 high speed prescaler for the 1/2 and 1/16 harmonic output frequency.The design of the VCO used push-push structure,the 24 GHz VCO have lower phase noise compared to the traditional design which used the low frequency VCO chips and frequency multiplier cascade technology.The measured results show that the phase noise is-92 dBc/Hz@100 kHz.The VCO can provide frequency from 23 GHz to 25.5 GHz with the tuning voltage from 0 V to 13 V.Output power is 9 dBm with 5 V DC supply.The VCO's phase noise performance is excellent over different temperature,shock and other conditions due to the VCO's monolithic push-push structure.The 1/2 harmonic and divided-by-8 high speed prescaler for a 1/16 harmonic output frequency also provide excellent performance.%介绍了一款基于砷化镓异质结双极晶体管(GaAs HBT)工艺的24 GHz单片压控振荡器(VCO),VCO芯片上同时集成了1/2次谐波输出及八分频器电路,可提供1/2和1/16次谐波输出.由于振荡器采用了推-推压控振荡器(push-push VCO)结构,相比传统的通过低频VCO芯片和倍频器级联技术实现的24 GHz VCO具有更低的相位噪声,测试结果表明芯片在不同温度、振动以及其他条件下表现出良好的相位噪声,在0~13V的电调电压条件下输出频率为23~25.5 GHz,输出功率在5 V直流工作电压条件下为9 dBm,相位噪声低至-92 dBc/Hz@100 kHz.同时1/2次谐波输出及八分频器电路提供的1/16次谐波输出性能良好.

  4. Silicon-Germanium Voltage-Controlled Oscillator at 105 GHz

    Science.gov (United States)

    Wong, Alden; Larocca, Tim; Chang, M. Frank; Samoska, Lorene A.

    2011-01-01

    A group at UCLA, in collaboration with the Jet Propulsion Laboratory, has designed a voltage-controlled oscillator (VCO) created specifically for a compact, integrated, electronically tunable frequency generator useable for submillimeter- wave science instruments operating in extreme cold environments.

  5. A Voltage Controlled Oscillator using Ring Structure in CMOS Technology

    Directory of Open Access Journals (Sweden)

    Mrs. Devendra Rani

    2012-06-01

    Full Text Available Voltage-Controlled Ring Oscillators are crucial components in many wireless communication systems. The goal of this project is to design a high speed and lower power consumption, a voltage controlled oscillator (VCO, based on ring oscillators in 250nm CMOS technology, which provides a frequency of 2.4GHz. This CMOS based VCO is used for high speed wireless communication applications. A design of VCO includes delay cell, bias circuitry, and tuning circuitry using Tanner 13.0v software.

  6. Voltage-controlled photonic oscillator.

    Science.gov (United States)

    Savchenkov, A A; Ilchenko, V S; Liang, W; Eliyahu, D; Matsko, A B; Seidel, D; Maleki, L

    2010-05-15

    We report the development and demonstration of an X-band voltage-controlled photonic oscillator based on a whispering gallery mode resonator made of an electro-optic crystalline material. The oscillator has good spectral purity and wide, agile, linear tunability. We have modified the existing theoretical model of the opto-electronic oscillator to describe the performance of our tunable oscillator and have found a good agreement between the theoretical predictions and the measurement results. We show that the device is promising for higher-frequency applications where high-performance tunable oscillators with wide tunability do not exist.

  7. On the investigation of voltage controlled oscillator phase noise for IoT applications

    Directory of Open Access Journals (Sweden)

    Haddad F.

    2016-01-01

    Full Text Available Voltage controlled oscillator (VCO is one of the key elements in radio frequency (RF transceivers. A VCO working at 2.4 GHz and designed in CMOS technology is presented. It is suitable for low-cost and low-noise applications using wireless standards such as ZigBee, Bluetooth, Wi-Fi and WPAN (Wireless Personal Area Network. The noise characteristics of this RF VCO are investigated. Noise measurements, especially, phase noise are achieved under different environmental conditions.

  8. A voltage-controlled ring oscillator using InP full enhancement-mode HEMT logic

    Science.gov (United States)

    Rui, Du; Yang, Dai; Yanling, Chen; Fuhua, Yang

    2009-03-01

    A voltage-controlled ring oscillator (VCO) based on a full enhancement-mode InAlAs/InGaAs/InP high electron mobility transistor (HEMT) logic is proposed. An enhancement-mode HEMT (E-HEMT) is fabricated, whose threshold is demonstrated to be 10 mV. The model of the E-HEMT is established and used in the SPICE simulation of the VCO. The result proves that the full E-HEMT logic technology can be applied to the VCO. And compared with the HEMT DCFL technology, the complexity of our fabrication process is reduced and the reliability is improved.

  9. A voltage-controlled ring oscillator using InP full enhancement-mode HEMT logic

    Institute of Scientific and Technical Information of China (English)

    Du Rui; Dai Yang; Chen Yanling; Yang Fuhua

    2009-01-01

    A voltage-controlled ring oscillator (VCO) based on a full enhancement-mode InAIAs/InGaAs/InP high electron mobility transistor (HEMT) logic is proposed. An enhancement-mode HEMT (E-HEMT) is fabricated, whose threshold is demonstrated to be 10 mV. The model of the E-HEMT is established and used in the SPICE simulation of the VCO. The result proves that the full E-HEMT logic technology can be applied to the VCO. And compared with the HEMT DCFL technology, the complexity of our fabrication process is reduced and the reliability is improved.

  10. Design and analysis of a three-stage voltage-controlled ring oscillator

    Science.gov (United States)

    Xuemei, Lei; Zhigong, Wang; Lianfeng, Shen

    2013-11-01

    This paper describes a large tuning range low phase noise voltage-controlled ring oscillator (ring VCO) based on a different cascade voltage logic delay cell with current-source load to change the current of output node. The method for optimization is presented. Furthermore, the analysis of performance of the proposed ring VCO is confirmed by the measurement results. The three-stage proposed ring VCO was fabricated in the 180-nm CMOS process of SMIC. The measurement results show that the oscillator frequency of the ring VCO is from 0.770 to 5.286 GHz and the phase noise is 97.93 dBc/Hz at an offset of 1 MHz from 5.268 GHz with a total power of 15.1 mW from a 1.8 V supply while occupying only 0.00175 mm2 of the core die area.

  11. Multichannel VCO needs only one reference

    Science.gov (United States)

    Masson, R. K.; Morenc, N. P.

    1979-01-01

    Frequency stabilizing circuit controls output of multichannel microwave oscillator using passband filters and selector logic to eliminate need for separate crystal diode voltage controlled oscillator (VCO).

  12. Voltage-controlled oscillator at 6 GHz for Doppler radar in heart sensing applications

    Directory of Open Access Journals (Sweden)

    Jovanović Predrag

    2009-01-01

    Full Text Available In this paper, the design of a low noise voltage controlled oscillator (VCO for heart sensing applications is presented. It is designed using Ansoft Designer software to have a low level of phase noise, therefore a bipolar transistor is chosen. Many effects such as the behavior of large signals, the parasitic effects of packages, etc., are taken into account. Hence, through a nonlinear analysis, quite accurate simulation results are provided.

  13. Phase noise analysis of voltage controlled oscillator used in cesium atomic clock

    Science.gov (United States)

    Zhi, Menghui; Tang, Liang; Qiao, Donghai

    2017-03-01

    Coherent population trapping (CPT) cesium frequency standard plays a significant role in precision guidance of missile and global positioning system (GPS). Low noise 4.596 GHz voltage controlled oscillator (VCO) is an indispensable part of microwave signal source in cesium frequency standard. Low-phase noise is also the most important and difficult performance indicator of VCO. Starting from phase noise analysis method proposed by Leeson, the formulas about the relationship between phase noise of output signal of oscillator feedback model and phase fluctuation spectrum of amplifier, phase noise of oscillator are derived in this paper. Finally, the asymptote model of microwave oscillator is proposed based on the formula derivation. The experiment shows that when the reverse bias voltage of variode is 1.8 V, the designed oscillation frequency of VCO is 4.596 GHz, the power is ‑1 dBm and the DC power consumption is 19.6 mW. The tendency of phase noise simulation curve and actual test curve conform to asymptote model. The phase noise in 1 and 10 kHz is, respectively, ‑60.86 and ‑86.58 dBc/Hz. The significance of the paper lies in determining the main factors influencing oscillator phase noise and providing guiding direction for the design of low-phase noise VCO.

  14. Hot carrier effects on jitter and phase noise in CMOS voltage-controlled oscillators

    Science.gov (United States)

    Zhang, Chi; Srivastava, Ashok

    2005-05-01

    The effects of hot carrier stress on CMOS voltage-controlled oscillators (VCO) are investigated. A model of the threshold voltage degradation in MOSFETs due to hot carrier stress has been used to model jitter and phase noise in voltage-controlled oscillators. The relation between the stress time which induces the hot carrier effects and the degradation of the VCO performance is presented. The VCO performance degradation takes into consideration decrease in operation frequency, increase in jitter and phase noise and decrease in tuning range. The experimental circuits have been designed in 0.5 μm n-well CMOS technology for operation at 3 V. It is shown that when the MOSFET threshold voltage, increases from 0.4 V to 0.9 V due to the hot carrier effect, for the single-ended ring oscillator, the oscillation frequency changes from 538 MHz to 360 MHz, and the phase noise changes from -104 dBc to -105 dBc at 1 MHz frequency offset with a power dissipation of 0.37 mW. For the current-starved VCO, the tuning range changes from 72 MHz - 287 MHz to 65.4 MHz - 201 MHz, and the phase noise changes from -109 dBc to -107 dBc at 1 MHz offset from the center frequency, 200 MHz; for the double-ended differential VCO, the tuning range changes from 32 MHz - 983 MHz to 26 MHz - 698 MHz, and phase noise changes from -86 dBc to -87 dBc at 1 MHz offset from the center frequency, 700 MHz.

  15. A dual-band quadrature VCO with gain proportional to oscillation frequency

    Science.gov (United States)

    Wenrui, Zhu; Haigang, Yang; Tongqiang, Gao; Hui, Zhang

    2013-08-01

    This paper presents a novel dual-band quadrature voltage controlled oscillator (VCO) with the gain proportional to the oscillation frequency. Frequency synthesizers with this VCO can reduce the bandwidth fluctuation over all the frequency ranges without compensation or calibration. Besides the original switched capacitor array, an extra switched varactor array is adopted for the implementation of the proposed VCO. The tuning technique of changing the values of the capacitor and varactor at the same ratio is also derived. For verification purposes, a 2.5 G/3.5 G dual-band quadrature VCO is fabricated in a 0.13 μm CMOS process for WiMAX applications. Measurement results show that the VCO gain is closely proportional to the oscillation frequency with ±16% variation over the entire frequency range. The phase noise is -138.15 dBc/Hz at 10 MHz from the 2.5 GHz carrier and -137.44 dBc/Hz at 10 MHz from the 3.5 GHz carrier.

  16. Continuation of the development of a millimeter wave wideband tunable waveguide voltage controlled oscillator

    Science.gov (United States)

    Mascioli, A.

    1990-05-01

    A waveguide voltage controlled oscillator (VCO) was designed for use in the 26 GHz to 40 GHz range. The VCO uses a novel approach involving a double radial line concept to provide tuning bandwidths in excess of 3 GHz at these frequencies. The system was modelled via an equivalent circuit and the various parameters influencing performance, particularly the tuning range, were analyzed. Software simulation of the system was developed to predict the behavior of the circuit. The simulation package allows for verification of assumptions made during the development of the equivalent circuit. Results obtained from the simulation are in agreement with those obtained experimentally. The simulation also verified that the Gunn diode capacitance and resistance exist within a certain known range. Their exact values must be determined empirically.

  17. The use of radial integrated circuits for the design of voltage-controlled oscillators

    Science.gov (United States)

    de Jaeger, M.

    A theoretical model for the behavior of voltage-controlled oscillators (VCO) used in millimeter-wave applications is presented, with attention concentrated on multi-diode structures. A radial structure is considered, featuring the VCOs operating in the Q band with ICs. The model developed examines the electromagnetic behavior of the circuit, taking into account multimodal functioning. Experimental results are presented for the frequency evolution with impedance. The design of a VCO, through integration of a Gunn diode and a varactor into a radial system, is described, including an analysis of the series resistance of the varactor. Optimum operational conditions are defined, as are device dimensions. Finally, the technique is extended to the design of power combiners.

  18. Programable Driver for Voltage-Controlled Oscillators

    Science.gov (United States)

    Fowler, L. E.; Mcneil, J. A.

    1985-01-01

    Electronically programable read-only memory (EPROM) and digital-to-analog converter provide customized time-varying voltage for frequency modulation. Voltage used to modulate IMPATT oscillator that serves as microwave pump for solid-state maser in low-noise amplifier. EPROM simple to tailor voltage waveform to suit characteristics of given maser. Digital information for waveform programed into EPROM chip; digital-to-analog converter reads information and produces corresponding analog wave. Principle readily adapted to other applications.

  19. A Low Phase Noise CMOS Quadrature Voltage Control Oscillator Using Clock Gated Technique

    Directory of Open Access Journals (Sweden)

    Jothi Baskar A

    2015-06-01

    Full Text Available This project presents the low phase noise cmos quadrature voltage control oscillator using clock gating technique. Here the colpitts vco is used to split the capacitance in the Qvco circuit producing quadrature output. The startup condition in the oscillator is improved by using enhancement [12].This QVCO performs the operation anti phase injection locking fordevice reuse [8]. The new clock gating technique is used to reduce the power with thepower supply 1.5v. The QVCO uses a 0.5mwith phase error of 0.4 and exhibits a phase noise of -118dBc/HZ at 1MHZ offset at the centre frequency of 500MHZ. Index terms: current switching, clock gating, phase noise, Qvco

  20. Design for Voltage Controlled Oscillator for GPS Frequency Adjustment%GPS校频的压控振荡器设计

    Institute of Scientific and Technical Information of China (English)

    李仲秋; 曾全胜

    2011-01-01

    Improvement of frequency stability and noise suppression ability of voltage controlled oscillation (VCO) is the key that the frequency standard production circuit obtains the high stability. high accuracy of standard frequency signals based on feedback control principle and GPS tame adjusting frequency technology. The comprehensive difference LC model VCO (using COMS capacitance array as LC component) is designed according to the advantages of difference model VCO and LC model VCO. The relationship of the VCO noise with frequency regulating scope and stable time was researched. It has a high control ability for power supply noise and basic noise. The emulation result indicates that the time of VCO frequency stability is short and the accuracy abides by the accuracy of GPS standard.%提高压控振荡器(VCO)的频率稳定度和嗓声抑制能力,是基于反馈控制原理与GPS驯服校频技术频标产生电路获得高稳定度、高准确率的标准频率信号的关键.综合差分对型VCO.LC型VCO的优点,研究压控振荡器的噪声与频率调节范围及稳定时间的关系,设计一种全差分结构的LC型压控振荡器(使用COW电容阵列作LC元件),具有较高的电源噪声和衬底噪声抑制能力.仿真结果表明,该压控振荡器的频率稳定时间短,准确度锁定在GPS标准的准确度上.

  1. A low-phase-noise Ka-band push-push voltage-controlled oscillator using CMOS/glass-integrated passive device technologies.

    Science.gov (United States)

    Wang, Sen

    2014-09-01

    In this paper, a Ka-band CMOS push-push voltage- controlled oscillator (VCO) integrated into a glass-integrated passive device (GIPD) process is presented. The transformer, λ/4 transmission line, and inductors of the VCO are realized in the GIPD process, achieving superior performances, and therefore improve the phase noise of the VCO. Moreover, the transformer-based VCO is a differential Hartley topology to further reduce the phase noise and chip area. Operating at 1.8 V supply voltage, the VCO core consumes merely 3.8 mW of dc power. The measured phase noise is -109.18 dBc/Hz at 1 MHz offset from the 30.84 GHz oscillation frequency. The push-push VCO also demonstrates a 24.5 dB fundamental rejection, and exhibits an 8.4% tuning range. Compared with recently published CMOS-based VCOs, it is observed that the proposed VCO exhibits excellent performance under low power consumption.

  2. Voltage-Controlled Sapphire Oscillator: Design, Development, and Preliminary Performance

    Science.gov (United States)

    Wang, R. T.; Dick, G. J.; Tjoelker, R. L.

    2007-08-01

    We present the design for a new short-term frequency standard, the voltage-controlled sapphire oscillator, as a practical and lower-cost alternative to a cryogenic sapphire oscillator operating at liquid helium temperatures. Performance goals are a frequency stability of 1 x 10^-14 (1 second equal to or less than tau equal to or less than 100 seconds), more than 2 years of continuous operation, and practical operability. Key elements include the sapphire resonator, low-power and long-life cryocooler, frequency compensation method, and cryo-Pound design. We report the design verification, experimental results, and test results of the cryocooler environmental sensitivity, as well as a preliminary stability measurement.

  3. A 12 GHz 30 mW 130 nm CMOS Rotary Travelling Wave Voltage Controlled Oscillator

    Directory of Open Access Journals (Sweden)

    G. Jacquemod

    2012-01-01

    Full Text Available This paper reports a 12 GHz rotary travelling wave (RTW voltage controlled oscillator designed in a 130 nm CMOS technology. The phase noise and power consumption performances were compared with the literature and with telecommunication standards for broadcast satellite applications. The RTW VCO exhibits a −106 dBc/Hz at 1 MHz and a 30 mW power consumption with a sensibility of 400 MHz/V. Finally, requirements are given for a PLL implementation of the RTW VCO and simulated results are presented.

  4. A comparison of MESFET and HEMT MMIC technologies using a compact Ka-band voltage-controlled oscillator

    Science.gov (United States)

    Swirhun, S.; Geddes, J.; Sokolov, Vladimir; Bosch, D.; Gawronski, M.; Anholt, R.

    1991-07-01

    To compare the capability of MESFET and HEMT technologies for monolithic microwave integrated circuit (MMIC) implementation we have fabricated and tested discrete field-effect transistors (FETs) and a novel Ka-band monolithic voltage controlled oscillator (VCO). We implemented the circuit with three different active devices: moderate- and high-doped ion-implanted MESFETs (metal-semiconductor FETs) and AlGaAs/GaAs HEMTs (high electron mobility transistors). A comparison of the measured oscillator phase-noise and an independent comparison of the temperature dependence of MESFET and HEMT RF equivalent circuits yields two general guidelines: MESFETs are preferred over HEMTs for applications requiring low phase-noise and temperature insensitive operation.

  5. Voltage-controlled narrowband and wide, variable-range four-segment quartz crystal oscillator.

    Science.gov (United States)

    Ruslan, Ruzaini; Satoh, Tomio; Akitsu, Tetsuya

    2012-03-01

    In this work, our goal is to develop a voltage-controlled variable-frequency quartz crystal oscillator with narrowband response, wide, variable frequency range and the capacity to oscillate across the series resonance frequency using a four-segment configuration of a quartz crystal oscillator. In conventional quartz oscillators, the quartz resonator is inserted in the feedback loop between the input and the output of the active circuit, providing sufficient gain and the phase relation. In the oscillator developed here, the quartz crystal resonator is inserted between the loop circuit and the ground potential. The performance of the voltage-controlled variable-frequency oscillator is demonstrated across the series resonance frequency.

  6. Design of CMOS Low Voltage Controlled Oscillators%低电压CMOS压控振荡器设计

    Institute of Scientific and Technical Information of China (English)

    刘华珠; 黄海云

    2011-01-01

    A low noise CMOS voltage controlled oscillator was designed and analyzed based on CSMC process. The basic theory and small signal model for the VCO were introduced. The performance of the VCO's phase noise and tuning rang were optimized by the LC noise filtering technology, proper circuit structure and device parameter. The circuit was simulated under supply voltage of 1.2 V. The frequency of the VCO ranges from 2. 24 GHz to 2. 57 GHz, the tail current is 3 mA, and the tuning range is about 13. 7%.%设计和分析了一种低电压CMOS压控振荡器,对设计的电路进行理论分析和模型建立,并使用仿真工具对电路进行验证和优化.设计中主要考虑相位噪声和调谐宽度等指标,通过采用电感电容滤波技术以及合理调整电路结构和元器件参数,使相位噪声和调谐宽度均达到了较高的性能指标.结果表明,在1.2 V工作电压下,设计的VCO的尾电流为3 mA,输出振荡频率为2.24~2.57 GHz,中心频率约为2.4 GHz,调谐范围达到13.7%.

  7. Compensation of temperature frequency pushing in microwave resonator-meters on the basis VCO

    Directory of Open Access Journals (Sweden)

    Drobakhin O. O.

    2008-02-01

    Full Text Available It is shown that the influence of temperature oscillations on the error of measurements of parameters in the case of the application of microwave resonator meters on the basis of a voltage-controlled oscillator (VCO can be minimized by software using a special algorithm of VCO frequency setting correction. An algorithm of VCO frequency setting correction for triangle control voltage is proposed.

  8. A Simple Voltage Controlled Oscillator Using Bootstrap Circuits and NOR-RS Flip Flop

    Science.gov (United States)

    Chaikla, Amphawan; Pongswatd, Sawai; Sasaki, Hirofumi; Fujimoto, Kuniaki; Yahara, Mitsutoshi

    This paper presents a simple and successful design for a voltage controlled oscillator. The proposed circuit is based on the use of two identical bootstrap circuits and a NOR-RS Flip Flop to generate wide-tunable sawtooth and square waves. Increasing control voltage linearly increases the output oscillation frequency. Experimental results verifying the performances of the proposed circuit are in agreement with the calculated values.

  9. A 23 GHz low power VCO in SiGe BiCMOS technology

    Institute of Scientific and Technical Information of China (English)

    Huang Yinkun; Wu Danyu; Zhou Lei; Jiang Fan; Wu Jin; Jin Zhi

    2013-01-01

    A 23 GHz voltage controlled oscillator (VCO) with very low power consumption is presented.This paper presents the design and measurement of an integrated millimeter wave VCO.This VCO employs an on-chip inductor and MOS varactor to form a high Q resonator.The VCO RFIC was implemented in a 0.18 μm 120 GHz ft SiGe hetero-junction bipolar transistor (HBT) BiCMOS technology.The VCO oscillation frequency is around 23 GHz,targeting at the ultra wideband (UWB) and short range radar applications.The core of the VCO circuit consumes 1 mA current from a 2.5 V power supply and the VCO phase noise was measured at around-94 dBc/Hz at a 1 MHz frequency offset.The FOM of the VCO is-177 dBc/Hz.

  10. A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, Sean [Univ. of Missouri, Rolla, MO (United States)

    2009-05-21

    Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrate and is fabricated by Peregrine Semiconductor corporation. This thesis work details the design of the Voltage Controlled Oscillator (VCO) portion of the PLL frequency synthesizer and constitutes an fully integrated VCO core circuit and a high-isolation buffer amplifier. The high-isolation buffer amplifier was designed to provide 16 dB of gain for 2200-3495 MHz as well as 60 dB of isolation for the oscillator core to provide immunity to frequency pulling due to RF load mismatch. Actual measurements of the amplifier gain and isolation showed the gain was approximately 5 dB lower than the simulated gain when all bond-wire and test substrate parasitics were taken into account. The isolation measurements were shown to be 28 dB at the high end of the frequency band but the measurement was more than likely compromised due to the aforementioned bond-wire and test substrate parasitics. The S-band oscillator discussed in this work was designed to operate over a frequency range of 2200 to 2300 MHz with a minimum output power of 0 dBm with a phase-noise of -92 dBc/Hz at a 100 kHz offset from the carrier. The tuning range was measured to be from 2215 MHz to 2330 MHz with a minimum output power of -7 dBm over the measured frequency range. A phase-noise of -90 dBc was measured at a 100 kHz offset from the carrier.

  11. Noise tolerant voltage-controlled LC oscillator circuits for deep submicron VLSI system-on-a-chip radio circuits

    OpenAIRE

    Typpö, Jukka

    2003-01-01

    This thesis studies the problems with maintaining the spectral purity of fully integrated VCO circuits for radio frequency synthesizers in single-chip system designs. LC tank circuit oscillator circuits are shown to convert amplitude variation in the tank circuit voltage into frequency modulation, if voltage dependent capacitances are present in the tank circuit. Since the parasitic capacitances of the gain transistors and the capacitance of the varactor device in a VCO circuit are voltage de...

  12. A new resonant circuit for 2.45 GHz LC VCO with linear frequency tuning

    OpenAIRE

    Zihir, Samet; Taşdemir, Ferhat; Tasdemir, Ferhat; Dinç, Tolga; Dinc, Tolga; Gürbüz, Yaşar; Gurbuz, Yasar

    2011-01-01

    A new MOS varactor bank is proposed to implement a 2.45 GHz SiGe BiCMOS LC-tank voltage controlled oscillator (VCO) with linear frequency tuning. Compared to a conventional VCO, the proposed technique improves the quality factor of the LC-tank while preserving the linearity of the circuit. Realized in 0.25-μm SiGe BiCMOS technology, VCO exhibits 35% VCO gain (KVCO) variation from 2.29 to 2.66 GHz with a 16% tuning ratio. The VCO also exhibits a phase noise of -113 dBc/Hz at 1 MHz offset fr...

  13. Low-Power CMOS VCO with Dual-Band Local Oscillating Signal Outputs for 5/2.5-GHz WLAN Transceivers

    Institute of Scientific and Technical Information of China (English)

    池保勇; 石秉学

    2003-01-01

    The paper describes a novel low-power CMOS voltage-controlled oscillator (VCO) with dual-band local oscillating (LO) signal outputs for 5/2.5-GHz wireless local area network (WLAN) transceivers. The VCO is based on an on-chip symmetrical spiral inductor and a differential varactor. The 2.5-GHz quadrature LO signals are generated using the injection-locked frequency divider (ILFD) technique. The ILFD structure is similar to the VCO structure with its wide tracking range. The design tool ASITIC was used to optimize all on-chip symmetrical inductors. The power consumption was kept low with differential LC tanks and the ILFD technique. The circuit was implemented in a 0.18-μm CMOS process. Hspice and SpectreRF simulations show the proposed circuit could generate low phase noise 5/2.5-GHz dual band LO signals with a wide tuning range. The 2.5-GHz LO signals are quadrature with almost no phase and amplitude errors. The circuit consumes less than 5.3 mW in the tuning range with a power supply voltage of 1.5 V. The die area is only 1.0 mm×1.0 mm.

  14. Performance Analysis of Variation in Power Consumption and Frequency on Different Topologies of Ring VCO in 70 nm CMOS Technology

    Directory of Open Access Journals (Sweden)

    Sumant Katiyal

    2012-07-01

    Full Text Available The proposed work describes the performance evaluation ofdifferent types of ring oscillator Voltage Controlled Oscillatortopologies on the basis of two characteristic parameters powerand frequency in 70 nm CMOS technology. The varioustopologies analyzed include Current Starved VCO, VCO withGates of PMOS Transistor Grounded, VCO with PMOS DiodeConnected, VCO with NMOS Diode Connected, VCO withvoltage applied to both PMOS and NMOS Transistor.Simulation of different parameters of ring oscillator VCO iscarried out on Tanner tool Version 13. VCO topologies areevaluated on the basis of frequency and power consumption bytaking lower supply voltage of 1.2 V. Performance evaluationand comparison of different topologies results in minimumpower consumption of 0.57 uW by Current Starved VCOtopology and maximum operating frequency of 0.57 MHz byVCO with Gates of PMOS Transistor Grounded.

  15. CMOS Voltage-Controlled Oscillator Resilient Design for Wireless Communication Applications

    Directory of Open Access Journals (Sweden)

    Ekavut Kritchanchai

    2015-08-01

    Full Text Available Semiconductor process variation and reliability aging effect on CMOS VCO performance has been studied. A technique to mitigate the effect of process variations on the performances of nano-scale CMOS LC-VCO is presented. The LC-VCO compensation uses a process invariant current source. VCO parameters such as phase noise and core power before and after compensation over a wide range of variability are examined. Analytical equations are derived for physical insight. ADS and Monte-Carlo simulation results show that the use of invariant current source improves the robustness of the VCO performance against process variations and device aging.

  16. An X-Band low-power and low-phase-noise VCO using bondwire inductor

    OpenAIRE

    Hu, K.; F. Herzel; Scheytt, J. C.

    2009-01-01

    In this paper a low-power low-phase-noise voltage-controlled-oscillator (VCO) has been designed and, fabricated in 0.25 μm SiGe BiCMOS process. The resonator of the VCO is implemented with on-chip MIM capacitors and a single aluminum bondwire. A tail current filter is realized to suppress flicker noise up-conversion. The measured phase noise is −126.6 dBc/Hz at 1 MHz offset from a 7.8 GHz carrier. The figure of merit (FOM) of the VCO is −192.5 dBc/Hz and the VCO cor...

  17. A LC Voltage-Controlled Oscillator Design and Simulation%低相位噪声压控振荡器的设计及仿真

    Institute of Scientific and Technical Information of China (English)

    梁爽; 曹娟

    2014-01-01

    With the rapid improvement on the communication technology of RF transceiver , high performance voltage-controlled oscillator has been the key link of analog integrated circuit design , production and implementation .Focus on the problem of phase noise ,a design for a 1 .115 GHz LC VCO is proposed in TSMC 0.18 μm CMOS process .The circuit is simulated by the SpectreRF in Cadence .The simulation results presented that the VCO voltage adjustment range is 4 V to 6 V ,and output frequency range is 1 .114 69 GHz to 1 .115 38 GHz .Phase noise at an offset of 10 kHz ,100 kHz and 1M Hz are -90 .9 dBc/Hz ,-118 .6 dBc/Hz and -141 .3 dBc/Hz ,respectively .In order to enhance the VCO noise performance ,the paper’s purpose is as much as possible to exchange narrow frequency for good phase noise .%随着通信技术对射频收发机性能要求的提高,高性能压控振荡器已成为模拟集成电路设计、生产和实现的关键环节.针对压控振荡器设计过程中存在相位噪声这一核心问题,采用STMC 0.18μm CMOS工艺,提出了一种1.115 GHz的电感电容压控振荡器电路,利用Cadence中的SpectreRF对电路进行仿真.仿真结果表明:在4~6 V的电压调节范围内,压控振荡器的输出频率范围为1.11469~1.11538 G Hz ,振荡频率为1.115 G Hz时,在偏离中心频率10 kHz处、100 kHz处以及1M Hz处的相位噪声分别为-90.9 dBc/Hz ,-118.6 dBc/Hz ,-141.3 dBc/Hz ,以较窄的频率调节范围换取较好的相位噪声抑制,从而提高了压控振荡器的噪声性能.

  18. A wideband LC-VCO with small VCO gain variation and adaptive power control

    Institute of Scientific and Technical Information of China (English)

    Li Bin; Fan Xiangning; Wang Zhigong

    2012-01-01

    A wideband LC tank voltage-controlled-oscillator (VCO) is proposed.To solve the impacts ofwideband operation on VCO gain (Kvco) variation and start-up constraint,a binary-weighted varactor array and a binary-weighted negative resistance array all with optimal unit values are designed.Implemented in a 0.18 μm CMOS process,the proposed VCO shows a frequency tuning range from 1.9 to 3.1 GHz,with a current consumption varying accordingly from 14.2 to 4 mA from a 1.8 V supply.With the proposed Kvco suppression technique,the Kvco varies from 50 to 60 MHz/V in the entire frequency range.The measured phase noise is -117 dBc/Hz at a 1 MHz offset from a 3 GHz carrier.

  19. Ring VCO Design with Variable Capacitance XNOR Delay Cell

    Science.gov (United States)

    Kumar, Manoj; Arya, Sandeep; Pandey, Sujata

    2015-12-01

    This paper presents the new designs of voltage controlled oscillator (VCO) with three transistors XNOR gate as variable capacitive load. Design of three, five and seven stage VCO have been reported using single ended ring topology. CMOS inverter based delay cell is modified with addition of XNOR capacitive load. Output frequency has been controlled by applied voltage to variable capacitive load. Control voltage of VCO has been varied from 1.3 to 2.1 V. Three stage VCO provides output frequency variation in the range of 3.52-3.34 GHz with power consumption variation from 0.81 to 1.76 mW. Five stage VCO shows frequency variation from 2.06 to 1.98 GHz with power consumption varying from 1.35 to 2.94 mW. Moreover, frequency of seven stage VCO varies from 1.47 to 1.41 GHz with varying power from 1.89 to 4.12 mW. Power consumption and output frequency of proposed VCO circuits have been compared with earlier reported circuits and present approach shows considerable improvements.

  20. Electronically Tunable Dual-Input Integrator Employing a Single CDBA and a Multiplier: Voltage Controlled Quadrature Oscillator Design

    Directory of Open Access Journals (Sweden)

    R. Nandi

    2009-01-01

    Full Text Available A new dual-input differential input active integrator using a current differencing buffered amplifier (CDBA is proposed. A multiplier element is appropriately used in the circuit whose control voltage (Vc tunes the integrator time constant (τ electronically. The design of a voltage controlled quadrature oscillator (VCQO based on the proposed integrator had been satisfactorily implemented. A new type of measurement for the tuning error of the oscillator based on the Nyquist plot is presented that shows an error of only 2% at fo≈ 1 MHz with Total Harmonic Distortion (THD less than 3%.

  1. Low phase noise GaAs HBT VCO in Ka-band

    Science.gov (United States)

    Ting, Yan; Yuming, Zhang; Hongliang, Lü; Yimen, Zhang; Yue, Wu; Yifeng, Liu

    2015-02-01

    Design and fabrication of a Ka-band voltage-controlled oscillator (VCO) using commercially available 1-μm GaAs heterojunction bipolar transistor technology is presented. A fully differential common-emitter configuration with a symmetric capacitance with a symmetric inductance tank structure is employed to reduce the phase noise of the VCO, and a novel π-feedback network is applied to compensate for the 180° phase shift. The on-wafer test shows that the VCO exhibits a phase noise of -96.47 dBc/Hz at a 1 MHz offset and presents a tuning range from 28.312 to 28.695 GHz. The overall dc current consumption of the VCO is 18 mA with a supply voltage of -6 V The chip area of the VCO is 0.7 × 0.7 mm2.

  2. An X-Band low-power and low-phase-noise VCO using bondwire inductor

    Directory of Open Access Journals (Sweden)

    K. Hu

    2009-05-01

    Full Text Available In this paper a low-power low-phase-noise voltage-controlled-oscillator (VCO has been designed and, fabricated in 0.25 μm SiGe BiCMOS process. The resonator of the VCO is implemented with on-chip MIM capacitors and a single aluminum bondwire. A tail current filter is realized to suppress flicker noise up-conversion. The measured phase noise is −126.6 dBc/Hz at 1 MHz offset from a 7.8 GHz carrier. The figure of merit (FOM of the VCO is −192.5 dBc/Hz and the VCO core consumes 4 mA from a 3.3 V power supply. To the best of our knowledge, this is the best FOM and the lowest phase noise for bondwire VCOs in the X-band. This VCO will be used for satellite communications.

  3. Inverse Sine Phase Detector Phase Locked Loop Associated with Modified Multi Band LC Quadrature Voltage Controlled Oscillator for Wireless Communication Systems at 0.9, 1.8, 2.4, 3.5 GHz

    Directory of Open Access Journals (Sweden)

    Mahmoud Abdellaoui

    2009-01-01

    Full Text Available Problem statement: In this study and in consequence of the restricted performance of the multi standard wireless receiver utilizing the classical architectures, we proposed and presented a new architecture of multi band wireless receiver based on an Inverse Sine Phase Detector Phase Locked Loop (ISPDPLL associated with modified multi band LC quadrature Voltage Controlled Oscillator (VCO, supporting GSM/DCS/DECT/Bluetooth/WiMax systems. Approach: To accomplish the multi standard receiving architecture at sufficiently good performance and at a low hardware cost, the proposed circuit, using an ISPDPLL associated with VCO based on switched capacitors utilizing a several numeric controlled capacitive branch and cross-coupled transistors, was implemented in 0.35 µm CMOS technology and designed to yield quadrature output signals (I-Q allowing to eliminate the dephasing block (90° employed in a multi band Zero IF architecture receiver, that make the proposed architecture amenable for monolithic integration and 4G multi standard application. Results: This novel system presented high performance and good potentiality to cover perfectly the wireless multi standard receiving on the large band with the same transmission condition. Conclusion/Recommendations: The performance of this system was analyzed and demonstrated to have a minimum phase noise, a good Factor Of Merit (FOM and wide tuning for these standard applications.

  4. Low-Voltage Process-Compensated VCO with On-Chip Process Monitoring and Body-Biasing Circuit Techniques

    OpenAIRE

    Ueno, Ken; Hirose, Tetsuya; Asai, Tetsuya; Amemiya, Yoshihito

    2009-01-01

    A voltage-controlled oscillator (VCO) tolerant to process variations at lower supply voltage was proposed. The circuit consists of an on-chip threshold-voltage-monitoring circuit, a current-source circuit, a body-biasing control circuit, and the delay cells of the VCO. Because variations in low-voltage VCO frequency are mainly determined by that of the current in delay cells. a current-compensation technique was adopted by using an on-chip threshold-voltage-monitoring circuit and body-biasing...

  5. Design of Low Phase Noise Voltage Controlled Oscillator with Low Tuning-gain Change and Wide Linear Range%低增益变化宽线性范围低噪声压控振荡器设计

    Institute of Scientific and Technical Information of China (English)

    郑金汪; 陈华; 倪侃; 郭桂良; 张润曦; 刘生有; 来强涛; 阎跃鹏

    2014-01-01

    Based on 0 .18 μm CMOS process ,a low power low phase noise broadband VCO with low tuning-gain change constant tuning curve interval and constant output swing was presented .Switched capacitor array ,varactor array with bias voltage and the tail current array was included in this VCO .The tuning range of VCO is 1 .153~1.911 GHz(49 .5% ) .The coverage of adjacent tuning curve is more than 50% .The tuning-gain of VCO is 45 .5~52.7 M Hz/V (13 .7% ) .The space of adjacent tuning curve is 43 .2~45 .9 M Hz(5 .9% ) .The output swing of VCO is 694~715 mV(3% ) .The linear range of tuning curve is 0 .2~1 .6 V(1 .4 V) .At a 1 .8 V supply and the center frequency 1 .53 GHz ,the VCO measures a phase noise of-130 .5 dBc/Hz@ 1 MHz offset while dissipating 3 .2 mA current .T he FOM of the VCO is -186 .5 dBc/Hz .%应用 TSMC 0.18μm CMOS工艺设计了一款低调谐增益变化,恒定调谐曲线间隔,恒定输出摆幅的低功耗低噪声宽带压控振荡器(Voltage Controlled Oscillator ,VCO).本振荡器的振荡频率覆盖1.153~1.911 GHz (49.5%)范围,相邻调谐曲线的覆盖范围大于50%,调谐增益变化范围为45.5~52.7 M Hz/V (13.7%),相邻调谐曲线间距变化范围为43.2~45.9 M Hz(5.9%),VCO输出波形的峰峰值为694~715 mV (3%),调谐曲线的线性范围为0.2~1.6V(1.4V).在1.8V的电源电压下,VCO在中心频率1.53GHz处耗电电流为3.2mA,相位噪声在1 M Hz频偏处为-130.5 dBc/Hz ,FOM值为-186.5 dBc/Hz .

  6. 锁相环电路中压控振荡器的SET响应研究%Research on Single-Event Transients in Voltage-Controlled Oscillators of Phase-Locked Loops

    Institute of Scientific and Technical Information of China (English)

    秦军瑞; 陈吉华; 赵振宇; 梁斌; 刘征

    2011-01-01

    Based on process calibration, single event transient in Voltage-Controlled Oscillators of high frequency Phase-Locked Loops in a 0.18μm bulk process is studied by the TCAD Mixed-mode simulation. The impact of voltage, LET and temperature on SET are studied. Our simulation results demonstrate that the max phase difference caused by the particles on VCO is weak when NMOS works in the cut-off region. The pulse error number caused by the particles on VCO increases linearly as LET increases, and when the device temperature increases, the max phase difference on VCO also generally increases.%空间辐射环境中的锁相环在SET作用下,将产生频率或相位偏差,甚至导致振荡中止,造成通信或功能中断.压控振荡器是锁相环中的关键电路,也是对SET最为敏感的部件之一.本文基于工艺校准的器件模型,采用TCAD混合模拟的方法,针对180nm体硅CMOS工艺下高频锁相环中的压控振荡器,研究了偏置条件、入射粒子的能量以及温度对压控振荡器SET响应的影响,通过分析失效机理,以指导抗辐照压控振荡器的设计.研究结果表明,当器件工作在截止区时,入射粒子引起压控振荡器输出时钟的最大相位差最小;压控振荡器的输出时钟错误脉冲数随着入射粒子LET的增加而线性增加;随着器件工作温度的升高,轰击粒子引起压控振荡器输出时钟的最大相位差也是增大的.

  7. SEMICONDUCTOR INTEGRATED CIRCUITS: An enhanced close-in phase noise LC-VCO using parasitic V-NPN transistors in a CMOS process

    Science.gov (United States)

    Peijun, Gao; J, Oh N.; Hao, Min

    2009-08-01

    A differential LC voltage controlled oscillator (VCO) employing parasitic vertical-NPN (V-NPN) transistors as a negative gm-cell is presented to improve the close-in phase noise. The V-NPN transistors have lower flicker noise compared to MOS transistors. DC and AC characteristics of the V-NPN transistors are measured to facilitate the VCO design. The proposed VCO is implemented in a 0.18 μm CMOS RF/mixed signal process, and the measurement results show the close-in phase noise is improved by 3.5-9.1 dB from 100 Hz to 10 kHz offset compared to that of a similar CMOS VCO. The proposed VCO consumes only 0.41 mA from a 1.5 V power supply.

  8. A 65 nm CMOS high efficiency 50 GHz VCO with regard to the coupling effect of inductors

    Science.gov (United States)

    Yu, Ye; Tong, Tian

    2013-07-01

    A 50 GHz cross-coupled voltage controlled oscillator (VCO) considering the coupling effect of inductors based on a 65 nm standard complementary metal oxide semiconductor (CMOS) technology is reported. A pair of inductors has been fabricated, measured and analyzed to characterize the coupling effects of adjacent inductors. The results are then implemented to accurately evaluate the VCO's LC tank. By optimizing the tank voltage swing and the buffer's operation region, the VCO achieves a maximum efficiency of 11.4% by generating an average output power of 2.5 dBm while only consuming 19.7 mW (including buffers). The VCO exhibits a phase noise of -87 dBc/Hz at 1 MHz offset, leading to a figure of merit (FoM) of -167.5 dB/Hz and a tuning range of 3.8% (from 48.98 to 50.88 GHz).

  9. Spacecraft redesign to reduce microphonic response of a VCO component

    Science.gov (United States)

    Strain, J. C.; Mittal, S.

    1988-01-01

    Reaction wheel vibration was found to induce out of specification sidebands on the carrier frequencies of some spacecraft components containing mechanical voltage control oscillators (VCOs). Concurrent investigations were performed to redesign the VCOs to reduce their response to the wheel vibration, and to design a reaction wheel isolation system to reduce the vibration input to the affected components. Component level tests indicated that both efforts provided viable solutions. The redesigned VCO will be incorporated into future spacecraft in the series, while affected spacecraft already in production will be retrofitted with the reaction wheel isolation system.

  10. Design of a CMOS multi-mode GNSS receiver VCO

    Institute of Scientific and Technical Information of China (English)

    Long Qiang; Zhuang Yiqi; Yin Yue; Li Zhenrong

    2012-01-01

    A voltage-controlled oscillator (VCO) with dual stages of accumulation mode varactors for a multimode global navigation satellite system (GNSS) application,which adopts sigma-delta fractional-N technology in the synthesizer,is presented.The structure is selected to optimize the frequency coverage and tuning linearity,based on a general analysis of the parasitic capacitance in the coarse tuning switch bank cells,which cover the global positioning system (GPS) and Beidou (BD) bands.The VCO implemented in the 0.18 μm CMOS process can cover the GPS L1,BD B1,B2 and B3 bands with sufficient margin,and exhibits low phase noise by using this tuning curve linearization technique.The equalized Kvco characteristic behavior further offers a wide voltage tuning range and improves the stability of the closed loop.

  11. VCO PLL Frequency Synthesizers for Spacecraft Transponders

    Science.gov (United States)

    Smith, Scott; Mysoor, Narayan; Lux, James; Cook, Brian

    2007-01-01

    Two documents discuss a breadboard version of advanced transponders that, when fully developed, would be installed on future spacecraft to fly in deep space. These transponders will be required to be capable of operation on any deepspace- communications uplink frequency channel between 7,145 and 7,235 MHz, and any downlink frequency channel between 8,400 and 8,500 MHz. The document focuses on the design and operation of frequency synthesizers for the receiver and transmitter. Heretofore, frequency synthesizers in deep-space transponders have been based on dielectric resonator oscillators (DROs), which do not have the wide tuning bandwidth necessary to tune over all channels in the uplink or downlink frequency bands. To satisfy the requirement for tuning bandwidth, the present frequency synthesizers are based on voltage-controlled-oscillator (VCO) phase-locked loops (PLLs) implemented by use of monolithic microwave integrated circuits (MMICs) implemented using inGaP heterojunction bipolar transistor (HBT) technology. MMIC VCO PLL frequency synthesizers similar to the present ones have been used in commercial and military applications but, until now, have exhibited too much phase noise for use in deep-space transponders. The present frequency synthesizers contain advanced MMIC VCOs, which use HBT technology and have lower levels of flicker (1/f) phase noise. When these MMIC VCOs are used with high-speed MMIC frequency dividers, it becomes possible to obtain the required combination of frequency agility and low phase noise.

  12. High accuracy digital aging monitor based on PLL-VCO circuit

    Science.gov (United States)

    Yuejun, Zhang; Zhidi, Jiang; Pengjun, Wang; Xuelong, Zhang

    2015-01-01

    As the manufacturing process is scaled down to the nanoscale, the aging phenomenon significantly affects the reliability and lifetime of integrated circuits. Consequently, the precise measurement of digital CMOS aging is a key aspect of nanoscale aging tolerant circuit design. This paper proposes a high accuracy digital aging monitor using phase-locked loop and voltage-controlled oscillator (PLL-VCO) circuit. The proposed monitor eliminates the circuit self-aging effect for the characteristic of PLL, whose frequency has no relationship with circuit aging phenomenon. The PLL-VCO monitor is implemented in TSMC low power 65 nm CMOS technology, and its area occupies 303.28 × 298.94 μm2. After accelerating aging tests, the experimental results show that PLL-VCO monitor improves accuracy about high temperature by 2.4% and high voltage by 18.7%.

  13. Research on the Influence of Switching Frequency on Low-Frequency Oscillation in the Voltage-Controlled Buck-Boost Converter

    Directory of Open Access Journals (Sweden)

    Faqiang Wang

    2011-01-01

    Full Text Available The influence of switching frequency on the low-frequency oscillation in the voltage-controlled buck-boost converter is studied in this paper. Firstly, the mathematical model of this system is derived. And then, a glimpse at the influence of switching frequency on the low-frequency oscillation in this system by MATLAB/Simulink is given. The improved averaged model of the system is established, and the corresponding theoretical analysis is presented. It is found that the switching frequency has an important influence on the low-frequency oscillation in the system, that is, the low-frequency oscillation is easy to occur when the switching frequency is low. Finally, the effectiveness of the improved averaged model and the theoretical analysis are confirmed by circuit experiment.

  14. A Low Power Wide-band Voltage Controlled Oscillator for Global Navigation Satellite System Receiver%一种应用于全球导航卫星系统接收机的低功耗宽带压控振荡器

    Institute of Scientific and Technical Information of China (English)

    尹喜珍; 肖时茂; 马成炎; 叶甜春

    2012-01-01

    This paper presents a new low power small area wide-band Voltage Controlled Oscillator (VCO) for Global Navigation Satellite System (GNSS) receiver. The VCO is separated in two discrete working regions from the characteristic of all-band GNSS signals. The power and phase noise can be optimized individually, the complexity of VCO is reduced and the area is saved. A technique of tuning curve linearization is used; The conventional VCO problem of having narrow effective tuning range of control voltage ( Vctrl) is solved. A linear tuning curve in whole variation of Vctrl is kept, the Amplitude Modulation to Frequency Modulation (AM-FM) conversion is decreased, and the phase noise is allayed. The measured results show that the tuning range of frequency is 49.5%, the gain of VCO (Kvco) is constant when Vctrl varies from 0.1 to 0.9 V. Measured phase noise is lower than -120 dBc at 1 MHz offset, the entire VCO consumes 2 mA current, occupies 0.24 mm2 area. The proposed VCO is implemented in 0.13 p.m 1P6M process, and it is successfully applied to all-band GNSS receiver.%该文设计了一种应用于全球导航卫星系统(GNSS)射频接收芯片的新型低功耗小面积宽频率调节范围的压控振荡器(VCO).根据全波段GNSS信号的特点,将VCO分成两个离散的频率工作区域,可分别对这两个区域进行功耗、相位噪声的优化,减小了VCO结构的复杂度,并节省了芯片面积.利用调谐曲线线性化技术,克服了传统的VCO控制电压有效调节范围窄的问题,使VCO在整个控制电压范围内调节曲线线性,减小了幅度调制转频率调制(AM-FM),降低了相位噪声.测试结果显示,该VCO频率调节范围为49.5%,控制电压在0.1~0.9 V内,VCO增益(KVCO)恒定,当频率偏移为1 MHz时相位噪声小于-120 dBc/Hz,消耗电流2 mA,占用芯片面积为0.24mm2.提出的VCO在0.13 μm 1P6M工艺上实现,已成功应用于全波段GNSS接收机中.

  15. Wide range fully integrated VCO with new cells-based varactor

    Science.gov (United States)

    Marrero-Martin, Margarita; Gonzalez, Benito; Garcia, Javier; Khemchandani, Sunil L.; Hernandez, Antonio; del Pino, Javier

    2012-08-01

    This article presents a wide range inductance-capacitance voltage controlled oscillator (VCO) with a unit cells-based varactor. The unit cell represents the minimum possible integrated varactor based on p-n junction diodes, where N+ diffusions are central rectangles, surrounded by doughnut shaped P+ diffusions, with their respective contacts. The varactors are designed using the AMS 0.35 µm BiCMOS process. A physical model has been derived from the measurement of a set of eight fabricated varactors. Measurements indicate that the VCO, which is intended to be used in DVB-H, oscillates from 1.087 to 2.032 GHz, with a 61% tuning range. The phase noises of -124 dBc/Hz at 1 MHz offset and -108 dBc/Hz at 100 kHz offset are obtained.

  16. A 6 GHz high power and low phase noise VCO using an InGaP/GaAs HBT

    Institute of Scientific and Technical Information of China (English)

    王显泰; 申华军; 金智; 陈延湖; 刘新宇

    2009-01-01

    A 6 GHz voltage controlled oscillator (VCO) optimized for power and noise performance was designed and characterized. This VCO was designed with the negative-resistance (Neg-R) method, utilizing an InGaP/GaAs hetero-junction bipolar transistor in the negative-resistance block. A proper output matching network and a high Q stripe line resonator were used to enhance output power and depress phase noise. Measured central frequency of the VCO was 6.008 GHz. The tuning range was more than 200 MHz. At the central frequency, an output power of 9.8 dBm and phase noise of -122.33 dBc/Hz at 1 MHz offset were achieved, the calculated RF to DC efficiency was about 14%, and the figure of merit was -179.2 dBc/Hz.

  17. A 1.0 V differential VCO in 0.13μm CMOS technology*

    Institute of Scientific and Technical Information of China (English)

    Cao Shengguo; Han Kefeng; Tan Xi; Yan Na; Min Hao

    2011-01-01

    A differential complementary LC voltage controlled oscillator (VCO) with high Q on-chip inductor is presented. The parallel resonator of the VCO consists of inversion-mode MOS (I-MOS) capacitors and an on-chip inductor. The resonator Q factor is mainly limited by the on-chip inductor. It is optimized by designing a single turn inductor that has a simulated Q factor of about 35 at 6 GHz. The proposed VCO is implemented in the SMIC 0.13μm 1P8M MMRF CMOS process, and the chip area is 1.0 × 0.8 mm2. The free-running frequency is from 5.73 to 6.35 GHz. When oscillating at 6.35 GHz, the current consumption is 2.55 mA from a supply voltage of 1.0 V and the measured phase noise at 1 MHz offset is -120.14 dBc/Hz. The figure of merit of the proposed VCO is -192.13 dBc/Hz.

  18. A fully integrated VCO with a wide tuning range for DVB-H

    Science.gov (United States)

    Khemchandani, S. L.; Betancort, G.; del Pino Suarez, Javier; Alvarado, Unai; Goni-Iturri, Amaya; Hernandez, Antonio

    2007-05-01

    European standard DVB-T (Digital Video Broadcasting - Terrestrial) has already proven its exceptional features, including the possibility to receive broadcast services also with portable devices and even in receivers with a limited mobility such as cars. This paper presents a fully integrated LC voltage controlled oscillator (VCO) in a low cost 0.35 μm SiGe technology for DVB-H standard. To obtain VCO specifications system simulations have been done. The designed VCO is suitable to operate with ZERO and LOW IF receiver architectures. To integrate all the VCO components, it oscillates at double of the frequency band, from 940 to 1724 MHz. In order to sweep the whole frequency range, the tank is composed of an array of switched capacitors together with the varactors. The integrated inductors have been designed by electromagnetic simulations using Momentum(C). Techniques like using a capacitor divider, biasing the transistor for minimum noise and emitter degeneration have been utilized to improve phase noise requirements. The obtained phase noise is -108 dBc/Hz at 100 kHz offset and the power consumption, including the output buffers, is 28 mW.

  19. A 2.4 GHz high-linearity low-phase-noise CMOS LC-VCO based on capacitance compensation

    Energy Technology Data Exchange (ETDEWEB)

    Li Zhenrong; Zhuang Yiqi; Li Bing; Jin Gang; Jin Zhao, E-mail: allen_lzr@126.co [Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2010-07-15

    A 2.4 GHz high-linearity low-phase-noise cross-coupled CMOS LC voltage-controlled oscillator (VCO) is implemented in standard 0.18-{mu}m CMOS technology. An equalization structure for tuning sensitivity base on the three-stage distributed biased switched-varactor bank and the differential switched-capacitor bank is adopted to reduce the variations of the VCO gain, achieve high linearity, and optimize the phase-noise performance. Compared to the conventional VCO, the proposed VCO has more constant gain over the entire tuning range. The tuning range is about 18.7% from 2.23 to 2.69 GHz, and the phase noise is -95 dBc/Hz at 100-kHz offset and -117 dBc/Hz at 1-MHz offset from the carrier frequency of 2.42 GHz. The power dissipation is 2.1 mW from a 1.8 V power supply. The active area of this VCO is 500 x 810 {mu}m{sup 2}.

  20. Wide tuning-range CMOS VCO based on a tunable active inductor

    Science.gov (United States)

    Babaei Kia, Hojjat; Khari A'ain, Abu; Grout, Ian

    2014-01-01

    In this paper, a wide tuning-range CMOS voltage-controlled oscillator (VCO) with high output power using an active inductor circuit is presented. In this VCO design, the coarse frequency is achieved by tuning the integrated active inductor. The circuit has been simulated using a 0.18-µm CMOS fabrication process and presents output frequency range from 100 MHz to 2.5 GHz, resulting in a tuning range of 96%. The phase noise is -85 dBc/Hz at a 1 MHz frequency offset. The output power is from -3 dBm at 2.55 GHz to +14 dBm at 167 MHz. The active inductor power dissipation is 6.5 mW and the total power consumption is 16.27 mW when operating on a 1.8 V supply voltage. By comparing this active inductor architecture VCO with general VCO topology, the result shows that this topology, which employs the proposed active inductor, produces a better performance.

  1. A 3.16-7 GHz transformer-based dual-band CMOS VCO

    Science.gov (United States)

    Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

    2015-03-01

    A dual-band, wide tuning range voltage-controlled oscillator that uses transformer-based fourth-order (LC) resonator with a compact common-centric layout is presented. Compared with the traditional wide band (VCO), it can double frequency tuning range without degrading phase noise performance. The relationship between the coupling coefficient of the transformer, selection of frequency bands, and the quality factor at each band is investigated. The transformer used in the resonator is a circular asymmetric concentric topology. Compared with conventional octagon spirals, the proposed circular asymmetric concentric transformer results in a higher quality-factor, and hence a lower oscillator phase noise. The VCO is designed and fabricated in a 0.18-μm CMOS technology and has 75% wide tuning range of 3.16-7.01 GHz. Depending on the oscillation frequency, the VCO current consumption is adjusted from 4.9 to 6.3 mA. The measured phase noises at 1 MHz offset from carrier frequencies of 3.1, 4.5, 5.1, and 6.6 GHz are -122.5, -113.3, -110.1, and -116.8 dBc/Hz, respectively. The chip area, including the pads, is 1.2 × 0.62 mm2 and the supply voltage is 1.8 V. Project supported by the National High Technology Research and Development Program of China (No. 2011AA10305) and the National Natural Science Foundation of China (No. 60901012).

  2. A Low Phase Noise Fully Monolithic 6 GHz Differential Coupled NMOS LC-VCO

    Science.gov (United States)

    Moalla, Dorra Mellouli; Cordeau, David; Mnif, Hassene; Paillot, Jean-Marie; Loulou, Mourad

    2016-01-01

    A fully monolithic 6 GHz low-phase noise Voltage-Controlled-Oscillator (VCO) is presented in this paper. It consists in two LC-NMOS differential VCOs coupled through a resistive network and is implemented on a 0.25 µm BiCMOS SiGe process. This proposed integrated VCO can be used also for phased-array applications to steer the beam over the entire spatial range. In this case, the radiation pattern of the phased antenna array is steered in a particular direction by establishing a constant phase progression in the oscillator chain which can be obtained by detuning the free-running frequencies of the two oscillators in the array. At 2.5 V power supply voltage and a power dissipation of 62.5 mW, the coupled VCO array features a measured worst case phase noise of -102.4 dBc/Hz and -125.64 dBc/Hz at 100 kHz and 1 MHz frequency offset respectively from a 6 GHz carrier. The tuning range is about 400 MHz, from 5.85 to 6.25 GHz, for a tuning voltage varying from 0 to 2.5 V.

  3. A fully integrated W-band push-push CMOS VCO with low phase noise and wide tuning range.

    Science.gov (United States)

    Wang, To-Po

    2011-07-01

    A circuit topology suitable for a low-phase-noise wide-tuning-range push-push voltage-controlled oscillator (VCO) is proposed in this paper. By applying varactors connected between drain and source terminations of the cross-coupled pair, the tuning range is effectively increased and the phase noise is improved. Moreover, a small capacitor is inserted between the VCO core and testing buffer to reduce loading effects on the VCO core. Furthermore, the enhanced second-harmonic output signal is extracted at middle of the varactors, leading to the elimination of RF choke at VCO's second-harmonic output port and a reduced chip size. Based on the proposed architecture, this VCO fabricated in 0.18-μm CMOS exhibits a measured 6.35% tuning range. Operating at a supply voltage of 1.2 V, the VCO core consumes 7.5-mW dc power, and the measured phase noise is -75 dBc/Hz and -91.5 dBc/Hz at 100-kHz and 1-MHz offsets from the 77.8-GHz carrier, respectively. Compared with previously published silicon-based VCOs over 70 GHz, this work can simultaneously achieve low phase noise, wide tuning range, and low dc power consumption, leading to a superior figure of merit (FOM), and better figure of merit considering the tuning range (FOM(T)). In addition, this fully integrated VCO also demonstrates the highest operation frequency among previously published 0.18-μm CMOS VCOs.

  4. A Ku-band wide-tuning-range high-output-power VCO in InGaP/GaAs HBT technology

    Science.gov (United States)

    Jincan, Zhang; Yuming, Zhang; Hongliang, Lü; Yimen, Zhang; Bo, Liu; Leiming, Zhang; Fei, Xiang

    2015-06-01

    A fully integrated Ku-band voltage controlled oscillator (VCO) is presented in an InGaP/GaAs heterojunction bipolar transistor (HBT) technology. To achieve the wide tuning range (TR), the VCO employs a Colpitts configuration, and the VCO simultaneously achieves high output power. The implemented VCO demonstrates an oscillation frequency range from 12.82 to 14.97 GHz, a frequency TR of 15.47%, an output power from 0.31 to 6.46 dBm, and a phase noise of -94.9 dBc/Hz at 1 MHz offset from 13.9 GHz center frequency. The VCO consumes 52.75 mW from 5 V supply and occupies an area of 0.81 × 0.78 mm2. Finally, the figures-of-merit for VCOs is discussed. Project supported by the National Basic Research Program of China (No. 2010CBxxxx05), the Advance Research Project of China (No. 51308xxxx06), the Advance Research Foundation of China (No. 9140A08xxxx11DZ111), and Doctoral Scientific Research Foundation of Henan University of Science and Technology (No. 400613480011), and the Foundation of He'nan Educational Commettee (No. 15A510001).

  5. Electrical Equivalent Model for an Optical VCO in a PLL Synchronization Scheme for Ultrashort Optical Pulse Sources

    Science.gov (United States)

    Bogoni, Antonella; Potì, Luca; Ponzini, Filippo; Ghelfi, Paolo

    2006-01-01

    The electrical modeling of complex electrooptical devices is a useful task for the correct design of its schemes and for the estimation of its performance. In this paper, we consider an electrooptical phase-locked loop (PLL) used to synchronize an RF system clock to the repetition rate of an optical pulsed source, realized by an active fiber mode-locking (ML) technique in the regenerative configuration. The synchronization scheme is suggested by a description of the pulsed source, for the first time, as an optical voltage-control oscillator (VCO). In particular, we present a simple new all-electrical model for the proposed optical VCO, and we verify its accuracy by the implementation of the whole PLL scheme at 2.5 and 10 GHz.

  6. A wide-band low phase noise LC-tuned VCO with constant KVCO/ωosc for LTE PLL

    Institute of Scientific and Technical Information of China (English)

    黄继伟; 王志功; 李奎利; 李正平; 王永平

    2012-01-01

    A wideband LC-tuned voltage-controlled oscillator (LC-VCO) applied in LTE PLL frequency synthesizers with constant KVCO/ωosc is described,In order to minimize the loop bandwidth variations of PLL,a varactor array is proposed,which consists of a series of differential variable capacitor pairs and a series of single-pole double-throw (SPDT) switches to connect Vtune or VDD.The switches are controlled by switching bits.With this scheme,the ratio of KV =(6)Cvar/(6)Vtune and the capacitance value of the capacitor array maintains relatively constant; furthermore,the loop bandwidth of the PLL fluctuation is suppressed.The 3.2-4.6-GHz VCO for multi-band LTE PLL is fabricated in a 0.13-μm RF-CMOS process.The VCO exhibits a maximum variation of KVCO/ωosc of only ±4%.The VCO also exhibits a low phase-noise of-124 dBc/Hz at a 1-MHz offset frequency and a low current consumption of 18.0 mA with a 1.2-V power supply.

  7. A Novel S-band VCO Based on LTCC Technology%基于LTCC技术S波段VCO研制

    Institute of Scientific and Technical Information of China (English)

    戴晓芒; 徐自强; 杨邦朝

    2011-01-01

    A novel VCO (voltage control oscillator) was designed and manufactured by LTCC technology, through a three-dimensional structure with passive components embedded in substrate. The models of embedded helical inductors and coupling capacitors which were helpful matching circuit were established by single circuit configuration. The output frequency of the LTCC VCO is 2. 0~2. 1 GHz,phase noise was -77 dBc/Hz@10 kHz,output power was 3 dBm,the outline dimensions were 10 mm× 10 mm× 1 mm, which were far less than the traditional VCO on PCB substrate . Accommodating with the miniature tendency.%采用低温共烧陶瓷(LTCC)技术,设计制作了一种新颖的压控振荡器(VCO).通过单电路结构,建立内埋螺旋式(Helical)结构电感和耦合电容模型,调整VCO匹配电路.测试结果表明,VCO输出频点为2.O~2.1 GHz,相位噪声为-77 dBc/Hz@10 kHz,输出功率为3 dBm.外形尺寸为10 mm×10 mm×1 mm,远小于传统印制电路板(PCB)基板VCO体积,适应系统小型化趋势.

  8. A wideband 0.13μm CMOS LC-VCO for IMT-advanced and UWB applications

    Institute of Scientific and Technical Information of China (English)

    Tang Xin; Huang Fengyi; Tang Xusheng; Shao Mingchi

    2013-01-01

    This paper presents an LC voltage controlled oscillator (VCO) in a dual-band frequency synthesizer for IMT-advanced and UWB applications.The switched current source,cross-coupled pair and noise filtering technique are adopted in this VCO design to improve the performance of the phase noise,power consumption,voltage amplitude,and tuning range.In order to achieve a wide tuning range,a reconfigurable LC tank with 4 bits switch control is adopted in the core circuit design.The size of the entire chip with pad is 1.11 × 0.98 mm2.The test results show that the current dissipation of the VCO at UWB and IMT-Advanced band is 3 mA and 4.5 mA in a 1.2 V supply.The tuning range of the designed VCO is 3.86-5.28 GHz and 3.14-3.88 GHz.The phase-noise at 1 MHz frequency offset from a 3.5 GHz and 4.2 GHz carrier is-123 dBc/Hz and-119 dBc/Hz,respectively.

  9. SEMICONDUCTOR INTEGRATED CIRCUITS: Design and realization of an ultra-low-power low-phase-noise CMOS LC-VCO

    Science.gov (United States)

    Xiushan, Wu; Zhigong, Wang; Zhiqun, Li; Jun, Xia; Qing, Li

    2010-08-01

    A fully integrated cross-coupled LC tank voltage-controlled oscillator (LC-VCO) using transformer feedback is proposed to achieve a low phase noise and ultra-low-power design even at a supply below the threshold voltage. The ultra-low-power VCO is implemented in the mixed-signal and RF 1P6M 0.18-μm CMOS technology of SMIC. The measured phase noise is -125.3 dBc/Hz at an offset frequency of 1 MHz from a carrier of 2.433 GHz, while the VCO core circuit draws only 640 μW from a 0.4-V supply. The designed VCO can cover a frequency range from 2.28 to 2.48 GHz. The tuning range of the circuit is 200 MHz (8.7%) and the FOM is -195.7 dB, which is suitable for an IEEE 802.11b receiver.

  10. A low-power time-domain VCO-based ADC in 65 nm CMOS

    Science.gov (United States)

    Chenluan, Wang; Shengxi, Diao; Fujiang, Lin

    2014-10-01

    A low-power, high-FoM (figure of merit), time-domain VCO (voltage controlled oscillator)-based ADC (analog-to-digital converter) in 65 nm CMOS technology is proposed. An asynchronous sigma—delta modulator (ASDM) is used to convert the voltage input signal to a square wave time signal, where the information is contained in its pulse-width. A time-domain quantizer, which uses VCO to convert voltage to frequency, is adopted, while the XOR (exclusive-OR) gate circuits convert the frequency information to digital representatives. The ASDM does not need an external clock, so there is no quantization noise. At the same time, the ASDM applies a harmonic-distortion-cancellation technique to its transconductance stage, which increases the SNDR (signal to noise and distortion ratio) performance of the ASDM. Since the output of the ASDM is a two-level voltage signal, the VCO's V—F (voltage to frequency) conversion curve is always linear. The XOR phase quantizer has an inherent feature of first-order noise-shaping. It puts the ADC's low-frequency output noise to high-frequency which is further filtered out by a low-pass filter. The proposed ADC achieves an SNR/SNDR of 54. dB/54.3 dB in the 8 MHz bandwidth, while consuming 2.8 mW. The FoM of the proposed ADC is a 334 fJ/conv-step.

  11. A low power CMOS VCO using inductive-biasing with high performance FoM

    Science.gov (United States)

    Weihao, Liu; Lu, Huang

    2016-04-01

    A novel voltage-controlled oscillator (VCO) topology with low voltage and low power is presented. It employed the inductive-biasing to build a feedback path between the tank and the MOS gate to enhance the voltage gain from output nodes of the tank to the gate node of the cross-coupled transistor. Theoretical analysis using time-varying phase noise theory derives closed-form symbolic formulas for the 1/f 2 phase noise region, showing that this feedback path could improve the phase noise performance. The proposed VCO is fabricated in TSMC 0.13 μm CMOS technology. Working under a 0.3 V supply voltage with 1.2 mW power consumption, the measured phase noise of the VCO is -119.4 dBc/Hz at 1 MHz offset frequency from the carrier of 4.92 GHz, resulting in an FoM of 192.5 dBc/Hz. Project supported by the National Science and Technology Major Project of China (No. 2011ZX03004-002-01).

  12. Development of a CMOS Oscillator Chain for Particle Detection based on SOI technology

    Energy Technology Data Exchange (ETDEWEB)

    Coulie-Castellani, K.; Ben Krit, S.; Rahajandraibe, W.; Aziza, H.; Portal, J-M. [Aix Marseille Universite, CNRS, Universite de Toulon, IM2NP UMR 7334, Marseille (France); Micolau, G. [Universite d' Avignon, UMR 1114 EMMAH, INRA-UAPV, Avignon (France)

    2015-07-01

    A new development of an oscillator concept, dedicated to the detection and tracking of particles with low fluxes, is presented. The solution is based on an indirect detection of the current generated at the input of the detection chain, through a Voltage Controlled Oscillator (VCO) response. The very first solution was proposed using bulk technology. This new development is based on SOI technology what makes it tolerant to radiations. (authors)

  13. A-189 dBc/Hz FoMT Wide Tuning Range VCO Using Q-Factor Enhancement Technique

    Science.gov (United States)

    Liu, Faen; Wang, Zhigong; Li, Zhiqun; Li, Qin; Wang, Rong; Yang, Geliang; Li, Zhu

    2015-06-01

    A 28-GHz voltage-controlled oscillator (VCO) with a wide tuning range and a low phase noise is presented in this paper. A PMOS-only cross-coupled pair with a lower flicker noise is exploited to provide the negative resistance. The mechanisms for enhancing the Q-factor of the LC tank at millimeter-wave (mm-wave) frequencies are analyzed and applied to optimize the proposed VCO design to obtain a low phase noise. To guarantee accurate oscillating frequencies, distributed interconnections are carefully modeled by EM simulations. Fabricated in a standard 90-nm CMOS process, the proposed VCO achieves a wide tuning range of 20.1 %, from 25 to 30.66 GHz and a low phase noise of -105.47 dBc/Hz at 1-MHz offset. The current of the core circuit is 10.5 mA under a single 1.2-V supply. The core area of the chip is 0.38 mm × 0.24 mm.

  14. Design of the Low Phase Noise VCO%低相位噪声VCO的设计

    Institute of Scientific and Technical Information of China (English)

    向永波; 阎跃鹏; 高海飞

    2012-01-01

    A low phase noise phase voltage controlled oscillator (VCO) for mobile communication repeater station was designed. Colpitts structure was adopted for the VCO, LC components was used as the resonator and BJT was used as the amplifier component. The frequency tuning range is from 730 MHz to 840 MHz with the output power of 10.7 dBm and the pressure control sensitivity of 22 MHz/V. At 800 MHz central frequency, the phase noise is -99. 42 dBc/Hz at 10 kHz offset, - 116. 44 dBc/Hz at 100 kHz offset and - 135. 06 dBc/Hz at 1 MHz offset separately. A low frequency filtering method at the base electrode was proposed to eliminate the spur, and no obvious spur was observed within the full test frequency band. The major phase noise source of the VCO was summarized, and the design method for the low noise VCO was given. The calculation result, simulation result and test result match well, which provides some references for the design of the low noise VCO.%设计了一个用于移动通信中继站的低相位噪声压控振荡器(VCO).该VCO采用了考皮兹结构,谐振器使用LC器件,放大器件使用双极结型晶体管(BJT).其频率调动范围为730~840MHz,压控灵敏度为22MHz/V,输出功率为10.7 dBm.在800MHz中心频率处,其实测相位噪声分别为-99.42dBc/Hz@10kHz,-116.44 dBc/Hz@100kHz,-135.06dBc/Hz@1 MHz.提出了一种采用基极低频滤波的办法消除VCO的杂散频率,整个测试频段内观察不到明显的杂散.阐述了VCO相位噪声的主要来源,给出了低噪声VCO的设计方法.理论计算,仿真结果和实物测试取得了一致的结论,对低噪声VCO的设计提供了一定的参考.

  15. DESIGN AND PERFORMANCE ANALYSIS OF VCO FOR STANDARD GSM USING MEMS

    Directory of Open Access Journals (Sweden)

    Khalid A. S. Al-Khateeb

    2010-05-01

    Full Text Available The design of a prototype monolithic Micro Electro-Mechanical Systems (MEMS electronic circuits, namely the Voltage Controlled Oscillators (VCOs is presented. The components can achieve the stringent requirements of wireless communication applications such as GSM cellular telephony. The VCO meets the low phase noise specifications of -136 dBc/Hz at large offset frequency of 3MHz, over the appropriate frequency range. The model of the monolithic VCO is based on the topology of the Colpitts Oscillator. It is relatively less complicated, which facilitates the practical integration of the MEMS components into the configuration. The variable capacitor and the monolithic 3-D coil inductor are suitable for low phase-noise and low power consumption at the application frequencies. A PSpice simulation model was developed with MEMS switching devices that can be integrated into the system. The model helps in determining the design parameters, which affect the performance and operation reliability of the RF transceiver system, for which a prototype has been tested and proved successful.

  16. Behavioral modeling of rf VCO circuit with MEMS LC resonator

    Science.gov (United States)

    Mohamed, Amal; Elsimary, Hamed; Ismail, Mohammed

    2001-04-01

    In this work, a behavioral Modeling of RF VCO circuit which has a tank designed by Microelectromechanical system (MEMS) technology is presented emphasizing robust design that can obtain the parametric variable of the suspended spiral inductor and the MEMS tunable capacitor to high performance and reliable design of the VCO circuit. The MEMS spiral inductor has a low phase noise effect on the VCO output, and the MEMS tunable capacitance has very high quality factor with enabling 20% change of oscillation frequency. The designed monolithic RF VCO circuit and the high-Q MEMS inductor and tunable capacitor are modeled using specter-s simulator in the CADENCE design framework and (Verilog-A) behavioral simulator. Complete monolithic fabrication of RF VCO with high-Q MEMS devices using standard CMOS process (MOSIS, AMI 1.2 micrometer).

  17. Designing a Ring-VCO for RFID Transponders in 0.18 μm CMOS Process

    Science.gov (United States)

    Jalil, Jubayer; Reaz, Mamun Bin Ibne; Bhuiyan, Mohammad Arif Sobhan; Rahman, Labonnah Farzana; Chang, Tae Gyu

    2014-01-01

    In radio frequency identification (RFID) systems, performance degradation of phase locked loops (PLLs) mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs). This paper proposes a low power, low phase noise ring-VCO developed for 2.42 GHz operated active RFID transponders compatible with IEEE 802.11 b/g, Bluetooth, and Zigbee protocols. For ease of integration and implementation of the module in tiny die area, a novel pseudodifferential delay cell based 3-stage ring oscillator has been introduced to fabricate the ring-VCO. In CMOS technology, 0.18 μm process is adopted for designing the circuit with 1.5 V power supply. The postlayout simulated results show that the proposed oscillator works in the tuning range of 0.5–2.54 GHz and dissipates 2.47 mW of power. It exhibits a phase noise of −126.62 dBc/Hz at 25 MHz offset from 2.42 GHz carrier frequency. PMID:24587731

  18. Designing a ring-VCO for RFID transponders in 0.18 μm CMOS process.

    Science.gov (United States)

    Jalil, Jubayer; Reaz, Mamun Bin Ibne; Bhuiyan, Mohammad Arif Sobhan; Rahman, Labonnah Farzana; Chang, Tae Gyu

    2014-01-01

    In radio frequency identification (RFID) systems, performance degradation of phase locked loops (PLLs) mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs). This paper proposes a low power, low phase noise ring-VCO developed for 2.42 GHz operated active RFID transponders compatible with IEEE 802.11 b/g, Bluetooth, and Zigbee protocols. For ease of integration and implementation of the module in tiny die area, a novel pseudodifferential delay cell based 3-stage ring oscillator has been introduced to fabricate the ring-VCO. In CMOS technology, 0.18 μm process is adopted for designing the circuit with 1.5 V power supply. The postlayout simulated results show that the proposed oscillator works in the tuning range of 0.5-2.54 GHz and dissipates 2.47 mW of power. It exhibits a phase noise of -126.62 dBc/Hz at 25 MHz offset from 2.42 GHz carrier frequency.

  19. Designing a Ring-VCO for RFID Transponders in 0.18 μm CMOS Process

    Directory of Open Access Journals (Sweden)

    Jubayer Jalil

    2014-01-01

    Full Text Available In radio frequency identification (RFID systems, performance degradation of phase locked loops (PLLs mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs. This paper proposes a low power, low phase noise ring-VCO developed for 2.42 GHz operated active RFID transponders compatible with IEEE 802.11 b/g, Bluetooth, and Zigbee protocols. For ease of integration and implementation of the module in tiny die area, a novel pseudodifferential delay cell based 3-stage ring oscillator has been introduced to fabricate the ring-VCO. In CMOS technology, 0.18 μm process is adopted for designing the circuit with 1.5 V power supply. The postlayout simulated results show that the proposed oscillator works in the tuning range of 0.5–2.54 GHz and dissipates 2.47 mW of power. It exhibits a phase noise of −126.62 dBc/Hz at 25 MHz offset from 2.42 GHz carrier frequency.

  20. A varactor tuned low-cost 24 GHz harmonic VCO

    Directory of Open Access Journals (Sweden)

    M. O. Olbrich

    2006-01-01

    Full Text Available We present a low-cost 24 GHz VCO that is based on a microstrip design combined with discrete packaged devices. The output frequency is generated by a harmonic oscillator. The tunabilty was reached using a varactor diode. Two versions of the VCO were built, one has a wide tuning range of 1.1 GHz and the other one has a high output power of 3.7 dBm.

  1. Phase-locked oscillator at 3 mm waveband using high Tc superconductor mixer mounted on pulse tube crycooler

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A frequency mixing and phase locking system is designed, in which electromagnetic shielding, microwave coupling, and intermediate frequency (IF) measurement arrangements are included. In lieu of liquid nitrogen, a pulse tube cryocooler is used to cool the whole system. With Josephson grain boundary junction as the mixing element, the 96th harmonic frequency mixing at 3 mm waveband is obtained, and phase-locked voltage- controlled oscillator (VCO) is realized.

  2. LC-Oscillator for 94 GHz Automotive Radar System Fabricated in SiGe:C BiCMOS Technology

    OpenAIRE

    2004-01-01

    This paper presents the design and measurement of a voltage-controlled oscillator (VCO) for the use in a 94 GHz automotive radar system and other applications. The oscillator has been fabricated in a 200 GHz SiGe:C BiCMOS technology with 0.25 µm minimum feature size. The oscillator is fully integrated on a single chip with a chip area of only 0.25 mm2. The fabricated oscillator has a tuning range of 2.2 GHz and a supply voltage of -3 Volt.

  3. A 3.2-GHz fully integrated low-phase noise CMOS VCO with self-biasing current source for the IEEE 802.11a/hiperLAN WLAN standard

    Science.gov (United States)

    Quemada, C.; Adin, I.; Bistue, G.; Berenguer, R.; Mendizabal, J.

    2005-06-01

    A 3.3V, fully integrated 3.2-GHz voltage-controlled oscillator (VCO) is designed in a 0.18μm CMOS technology for the IEE 802.11a/HiperLAN WLAN standard for the UNII band from 5.15 to 5.35 GHz. The VCO is tunable between 2.85 GHz and 3.31 GHz. NMOS architecture with self-biasing current of the tank source is chosen. A startup circuit has been employed to avoid zero initial current. Current variation is lower than 1% for voltage supply variations of 10%. The use of a self-biasing current source in the tank provides a greater safety in the transconductance value and allows running along more extreme point operation The designed VCO displays a phase noise and output power of -98dBc/Hz (at 100 KHz offset frequency) and 0dBm respectively. This phase noise has been obtained with inductors of 2.2nH and quality factor of 12 at 3.2 GHz, and P-N junction varactors whose quality factor is estimated to exceed 40 at 3.2 GHz. These passive components have been fabricated, measured and modeled previously. The core of the VCO consumes 33mW DC power.

  4. A multiple-pass ring oscillator based dual-loop phase-locked loop

    Institute of Scientific and Technical Information of China (English)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning

    2009-01-01

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-μm RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of-99 dBc/Hz @ 1 MHz offset from a 5.5 GHz carrier.

  5. A multiple-pass ring oscillator based dual-loop phase-locked loop

    Energy Technology Data Exchange (ETDEWEB)

    Chen Danfeng; Ren Junyan; Deng Jingjing; Li Wei; Li Ning, E-mail: dfchen@fudan.edu.c [State Key Laboratory of ASIC and System, Fudan University, Shanghai 201203 (China)

    2009-10-15

    A dual-loop phase-locked loop (PLL) for wideband operation is proposed. The dual-loop architecture combines a coarse-tuning loop with a fine-tuning one, enabling a wide tuning range and low voltage-controlled oscillator (VCO) gain without poisoning phase noise and reference spur suppression performance. An analysis of the phase noise and reference spur of the dual-loop PLL is emphasized. A novel multiple-pass ring VCO is designed for the dual-loop application. It utilizes both voltage-control and current-control simultaneously in the delay cell. The PLL is fabricated in Jazz 0.18-{mu}m RF CMOS technology. The measured tuning range is from 4.2 to 5.9 GHz. It achieves a low phase noise of -99 dBc/Hz - 1 MHz offset from a 5.5 GHz carrier.

  6. 一种中心频率可调的VCO电路设计%A Center Frequency Adjustable VCO Circuit Design

    Institute of Scientific and Technical Information of China (English)

    邢立冬; 蒋林

    2011-01-01

    A Voltage-controlled oscillator(VCO) for high speed phase-locked loops system designed with 0. 18 μm CMOS technology is presented in this paper. The center frequency of the circuit can be adjusted as needed. The circuit is simulated with SMIC 0. 18μm CMOS model by Virtuoso AMS Simulator. The results of simulation show that the performance of the VCO has achieved the design requirements completely which are 2. 125~3. 125 GHz output frequency range, -105dBc/Hz SSB(Single Side-Band) phase noise at a 5MHz offset.%采用0.18μm CMOS工艺设计了一种用于高速锁相环系统的压控振荡器(VCO)电路,该电路的中心频率可根据需要进行调节.电路采用SMIC 0.18 μm工艺模型,使用Cadence的Spectre工具进行了仿真,仿真结果表明,该电路可工作在2.125~3.125 GHz范围内,在5 MHz频偏处的相位噪声为-105 dBc/Hz.

  7. On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz

    Science.gov (United States)

    Samoska, Lorene; Man Fung, King; Gaier, Todd; Huang, Daquan; Larocca, Tim; Chang, M. F.; Campbell, Richard; Andrews, Michael

    2008-01-01

    The world s first silicon-based complementary metal oxide/semiconductor (CMOS) integrated-circuit voltage-controlled oscillator (VCO) operating in a frequency range around 324 GHz has been built and tested. Concomitantly, equipment for measuring the performance of this oscillator has been built and tested. These accomplishments are intermediate steps in a continuing effort to develop low-power-consumption, low-phase-noise, electronically tunable signal generators as local oscillators for heterodyne receivers in submillimeter-wavelength (frequency > 300 GHz) scientific instruments and imaging systems. Submillimeter-wavelength imaging systems are of special interest for military and law-enforcement use because they could, potentially, be used to detect weapons hidden behind clothing and other opaque dielectric materials. In comparison with prior submillimeter- wavelength signal generators, CMOS VCOs offer significant potential advantages, including great reductions in power consumption, mass, size, and complexity. In addition, there is potential for on-chip integration of CMOS VCOs with other CMOS integrated circuitry, including phase-lock loops, analog- to-digital converters, and advanced microprocessors.

  8. MPPT algorithm for voltage controlled PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco;

    2008-01-01

    This paper presents a novel concept for an MPPT that can be used in case of a voltage controlled grid connected PV inverters. In case of single-phase systems, the 100 Hz ripple in the AC power is also present on the DC side. Depending on the DC link capacitor, this power fluctuation can be used t...... to track the MPP of the PV array, using the information that at MPP the power oscillations are very small. In this way the algorithm can detect the fact that the current working point is at the MPP, for the current atmospheric conditions....

  9. Voltage controlled spintronics device for logic applications.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, S. D.; You, C.-Y.

    1999-09-03

    We consider logic device concepts based on our previously proposed spintronics device element whose magnetization orientation is controlled by application of a bias voltage instead of a magnetic field. The basic building block is the voltage-controlled rotation (VCR) element that consists of a four-layer structure--two ferromagnetic layers separated by both nanometer-thick insulator and metallic spacer layers. The interlayer exchange coupling between the two ferromagnetic layers oscillates as a function of applied voltage. We illustrate transistor-like concepts and re-programmable logic gates based on VCR elements.

  10. 一种高精度模数混合温度补偿晶体振荡器%A High-Precision Mixed-Signal Voltage-Controlled Crystal Oscillator with Temperature Compensation

    Institute of Scientific and Technical Information of China (English)

    刘会娟; 伍冬; 郑德平; 潘立阳; 许军

    2011-01-01

    A mixed-signal voltage-controlled crystal oscillator with temperature compensation was implemented in 0.18 ;*m standard CMOS process. The on-chip compensated network reduced memory capacity in digital network. The circuit needs neither floating-gate nor high-voltage CMOS transistor as required by conventional EEPROM/flash memory, which reduced chip cost and power consumption. Simulation results showed that the proposed circuit had a temperature frequency stability of 10'7 from -40 V to 85 *C, and the system consumed 1. 79 mA of power from 1. 8 V supply.%提出了一种对石英晶体振荡器进行温度补偿的模数混合方法.该补偿芯片基于0.18μm标准CMOS工艺实现.采用模拟补偿网络和基于非挥发存储器的数字补偿网络相叠加的方法,对晶体振荡器进行间接补偿,实现了数模混合的片式化,降低了存储器的容量.该方法不需要高压CMOS和EEPROM浮栅器件,降低了工艺成本和功耗.补偿结果显示,温度频率稳定度达到10-7/-40℃~85℃,系统功耗为1.79 mA@1.8 V.

  11. A class-C VCO based Σ-Δ fraction-N frequency synthesizer with AFC for 802.11ah applications

    Science.gov (United States)

    Xiaobao, Yu; Siyang, Han; Zongming, Jin; Zhihua, Wang; Baoyong, Chi

    2015-09-01

    A 1.4-2 GHz phase-locked loop (PLL) Σ-Δ fraction-N frequency synthesizer with automatic frequency control (AFC) for 802.11ah applications is presented. A class-C voltage control oscillator (VCO) ranging from 1.4 to 2 GHz is integrated on-chip to save power for the sub-GHz band. A novel AFC algorithm is introduced to maintain the VCO oscillation at the start-up and automatically search for the appropriate control word of the switched-capacitor array to extend the PLL tuning range. A 20-bit third-order Σ-Δ modulator is utilized to reduce the fraction spurs while achieving a frequency resolution that is lower than 30 Hz. The measurement results show that the frequency synthesizer has achieved a phase noise of < -120 dBc/Hz at 1 MHz offset and consumes 11.1 mW from a 1.7 V supply. Moreover, compared with the traditional class-A counterparts, the phase noise in class-C mode has been improved by 5 dB under the same power consumption.

  12. 电荷泵锁相环中压控振荡器的噪声设计%The Noise Design of Voltage Controlled Oscillator in Charge-pump PLL

    Institute of Scientific and Technical Information of China (English)

    李仲秋; 王文杰; 谢志明

    2007-01-01

    在分析争比较反相型VCO(压控振荡器)、差分对型VCO、LC型VCO工作原理和特点的基础上,综合差分对型和LC型VCO的优点,设计了一种全差分结构的LC型VCO(使用键合线等效电感及附加COMS电容阵列作为LC元件),具有较高的电源噪声和衬底噪声抑制能力.仿真结果表明,VCO工作频率范围1.98 GHz~2.06GHz,相位噪声-89 dBc/Hz.本VCO适合于低功耗设计.

  13. Linearity of Bulk-Controlled Inverter Ring VCO in Weak and Strong Inversion

    DEFF Research Database (Denmark)

    Wismar, Ulrik Sørensen; Wisland, Dag T.; Andreani, Pietro

    2005-01-01

    Frequency modulation in ring VCOs is investigated. Primarily, the linearity of conversion from input voltage to output frequency is considered. Bulk-voltage control of the threshold voltage of the VCO transistors is found to be a very promising approach for applications in frequency ΔΣ converters....... Different approaches apply in presence of high supply voltages, when transistors work in strong inversion, compared to low supply voltages, when transistors are in weak inversion. In strong inversion, second-order effects controlled by the supply voltage linearize the VCO modulation, while in weak inversion...

  14. Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator

    DEFF Research Database (Denmark)

    Tuan Vu, Cao; Wisland, Dag T.; Lande, Tor Sverre

    A low-voltage, low-power, and wide-tuning-range VCO which converts an analog input voltage to phase information for a frequency ΔΣ modulator is proposed in this paper. The VCO is based on a differential ring oscillator, which is improved with modified symmetric load and a positive feedback in the...

  15. A K-Band Push-Push VCO MMIC using embedded frequency doubling mechanism

    OpenAIRE

    Sim, Sang-Hoon; Ko, Sangsoo; Hong, Songcheol

    2004-01-01

    A K-Band Push-Push VCO MMIC which has small size, high output power and low phase noise is presented. This push-push VCO utilize the embedded frequency doubling mechanism of cross coupled topology. A commercial InGaP/GaAs HBT technology with the f T of 60 GHz and the fMAX of 110 GHz was used for the implementation. The oscillation frequency is from 21.02 GHz to 21.17 GHz. The peak output power of the VCO is 1.7dBm. The phase noise is -110dBc/Hz at 1MHz offset from 2...

  16. A 220-1100 MHz low phase-noise frequency synthesizer with wide-band VCO and selectable I/Q divider

    Science.gov (United States)

    Hua, Chen; Renjie, Gong; Xu, Cheng; Yulin, Zhang; Zhong, Gao; Guiliang, Guo; Yuepeng, Yan

    2014-12-01

    This paper presents a low phase-noise fractional-N frequency synthesizer which provides an in-phase/quadrature-phase (I/Q) signal over a frequency range of 220-1100 MHz for wireless networks of industrial automation (WIA) applications. Two techniques are proposed to achieve the wide range. First, a 1.4-2.2 GHz ultralow gain voltage-controlled oscillator (VCO) is adopted by using 128 tuning curves. Second, a selectable I/Q divider is employed to divide the VCO frequency by 2 or 3 or 4 or 6. Besides, a phase-switching prescaler is proposed to lower PLL phase noise, a self-calibrated charge pump is used to suppress spur, and a detect-boosting phase frequency detector is adopted to shorten settling time. With a 200 kHz loop bandwidth, lowest measured phase noise is -106 dBc/Hz at a 10 kHz offset and -131 dBc/Hz at a 1 MHz offset. Fabricated in the TSMC 0.18 μm CMOS process, the synthesizer occupies a chip area of 1.2 mm2, consumes only 15 mW from the 1.8 V power supply, and settles within 13.2 μs. The synthesizer is optimized for the WIA applications, but can also be used for other short-range wireless communications, such as 433, 868, 916 MHz ISM band applications.

  17. 7~11GHz CMOS环形压控振荡器的设计%Design of a 7-11 GHz Ring VCO Based on CMOS Process

    Institute of Scientific and Technical Information of China (English)

    何芝兰; 段吉海

    2011-01-01

    设计了一种全集成差分高速环形压控振荡器(VCO).采用三级延迟单元环路复用结构,通过正反馈技术以及改变负载电阻值的方法,有效优化延迟单元;采用双控制电压粗/细调谐方式,实现振荡器高频率、低功耗的要求.在SMIC 0.18μm CMOS RF工艺模型下,采用ADS软件对振荡电路进行仿真,在外接电源电压Vdd=1.8 V时,输出频率的调谐范围为7.32~11.07 GHz,当频率为11 GHz时,在偏离中心频率1 MHz处相位噪声为-88.32 dBc/Hz,在偏离中心频率10MHz处相位噪声为-112.7 dBc/Hz,平均功耗为63.5 mW.该VCO可应用于锁相环和雷达通信系统.%A fully integrated differential high-speed ring voltage-controlled oscillator (VCO) was designed, which was comprised of three-stage delay cell with multi-loop structure. The delay cell was optimized by using positive feedback and modifying load resistance value. In this circuit, high frequency and low power was realized by coarse/ fine frequency control. Based on SMIC's 0.18 um 1P6M CMOS process model, the VCO was simulated with ADS. At 1. 8 V supply voltage, the VCO had a linear tuning range from 7. 32 GHz to 11. 07 GHz. Simulation results showed that, for an oscillating frequency of 11 GHz, the circuit had a phase noise of -88. 32 dBc/Hz and -112. 7 dBc/Hz at 1 MHz and 10 MHz off center frequency, respectively, with an average power of 63. 5 mW.

  18. Stability Boundaries for Offshore Wind Park Distributed Voltage Control

    DEFF Research Database (Denmark)

    Gryning, Mikkel P.S.; Wu, Qiuwei; Kocewiak, Lukasz;

    2016-01-01

    In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park...... pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed...... forward filter design are given to obtain required disturbance rejection properties. The paper contributes by providing analytical relations between power plant control, droop, sampling time, electrical parameters and voltage control characteristics, and by assessing frequencies and damping of reactive...

  19. A Millimeter-wave CMOS VCO Using Distributed LC Tank%采用分布式谐振回路的毫米波 CMOS压控振荡器

    Institute of Scientific and Technical Information of China (English)

    孙凯; 张健; 刘昱; 李志强; 陈延湖

    2015-01-01

    设计了一款应用于毫米波频率综合器的压控振荡器(Voltage Controlled Oscillator ,VCO).振荡器谐振回路采用分布式电感电容结构,相比传统结构可以提高振荡频率,降低振荡所需的环路增益;优化谐振网络中电容的设计,提高调谐范围;电磁仿真毫米波段电感,提高品质因数,降低相位噪声.电路设计采用SM IC 40 nm 1P6M RF CMOS工艺.仿真结果表明,频率调谐范围为56.1~61.2 GHz(5.1 GHz ,8.7%),振荡中心频率处的相位噪声为-88dBc/Hz@1MHz.电源电压0.8V下,电路功耗为3.3mW.芯片核心面积为0.0135mm2.%A voltage controlled oscillator (VCO) was designed for millimeter‐wave band frequency synthesizer .The oscillation frequency was enhanced and the minimum required loop gain was decreased compared to the conventional structure by using the distributed LC tank . Frequency tuning range was enhanced by optimizing the design of capacitance in the LC tank . Differential inductor was designed and modeled for millimeter‐wave band using electromagnetic simulator .The quality factor and phase noise was improved due to the proposed inductor .The design is based on SMIC 40 nm 1P6M RF CMOS process .Post‐simulation shows that the VCO has a tuning range of 5 .1 GHz (8 .7% ) from 56 .1 GHz to 61 .2 GHz .The phase noise is‐88 dBc/Hz at 1 M Hz offset at the center frequency . The VCO consumes 3 .3 mW from a 0 .8 V power supply and the chip area is 0 .013 5 mm2 .

  20. An Ultra Wideband VHF CMOS LC VCO%超宽频带VHF频段CMOS LC VCO

    Institute of Scientific and Technical Information of China (English)

    宁彦卿; 王志华; 陈弘毅

    2006-01-01

    This paper presents a VHF CMOS VCO. The most significant improvement on the VCO is that the cross-coupled MOSFET pairs are divided into several switchable parts so the characteristics can compensate the state change that results from the frequency tuning of the oscillator. This VCO is implemented in 0.18μm CMOS with a core area of about 550μm × 700μm. The test results show that the tuning range covers 31~111MHz with a power consumption between 0.3~6.9mW and a phase noise at a 100kHz offset of about - 110dBc/Hz.%实现了一个宽频带VHF频段CMOS VCO.其最大的改进在于将振荡器中交叉耦合MOS管分为并联可开关的若干段.这样使其特性可以在较大范围内补偿VCO调频过程中状态的变化.该VCO使用标准0.18μmCMOS工艺制作,核心版图面积约为550μm×700μm.测试结果表明:该VCO频率覆盖范围为31~111MHz;功耗为0.3~6.9mW;在100kHz频偏处相位噪声约-110dBc/Hz.

  1. UAV Digital Tracking Array Design, Development and Testing

    Science.gov (United States)

    2009-12-01

    Voltage-Controlled Oscillator ( VCO ).................................... 57 b. Low-Power Amplifier (LPA...Receive TWS Track While Scan UAV Unmanned Aerial Vehicle USAF United States Air Force VCO Voltage Controlled Oscillator VI Virtual...Loop (PLL) Quadrature Detector A PLL consists of three main components: phase comparator, low pass filter (LPF) and voltage controlled oscillator ( VCO

  2. 卫星电视天线射频电路中LC压控振荡器设计%LC VCO Design of Satellite TV Antenna RF Circuit

    Institute of Scientific and Technical Information of China (English)

    王魏; 黎希; 宫召英; 马晓英; 杨丽君; 王岳生

    2012-01-01

    A monolithic integrated voltage controlled oscillator (VCO) with low power, low phase noise and wide tuning range used in the satellite TV antenna RF circuit is designed. The PMOS tail current source and a MIM capacitor array structure is used so as to effectively reduce the phase noise,and ensure the enough tuning range. The proposed VCO achieved a tuning rang of 3.364 -4.022 GHz,and the central frequency is 3.7 GHz,the phase noise is -90.4 dBc/Hz at 100 Hz and -119.1 dBc/Hz at 1 MHz offset while dissipating2.5 mW from 1.8 V supply.%设计了一款应用于卫星电视天线电路中低功耗、低相噪的宽带单片集成压控振荡器.该振荡器利用PMOS尾电流源和MIM电容阵列结构.在保证调谐范围的前提下,有效地降低了相位噪声.使得该压控振荡器实现了3.384 ~4.022 GHz频段的覆盖,在中心频率为3.7 GHz时,100 Hz和1 MHz频偏处的相位噪声分别为-90.4 dBc/Hz和-119.1 dBc/Hz,工作电压下为1.8V,功耗仅为2.5 mW.

  3. 1-GHz CMOS VCO design for wireless application using MEMS technology

    Science.gov (United States)

    Mohamed, Amal; Elsimary, Hamed; Ismail, Mohammed

    2000-04-01

    In this work, the design of RF VCO circuit, in which the oscillation frequency is controlled by a tunable capacitor based on microelectromechanical system (MEMS) technology is presented. The design of high Q-MEMS tunable capacitor has been accomplished through bulk micro machining with all metal micro structure. A standard CMOS process is used to carry out the fabrication of the VCO circuit with the MEMS tunable capacitor on the same chip. The main features of this design, is the enabling of a complete monolithic fabrication RF VCOs using on-chip IC compatible high-Q MEMS tunable capacitor. The performance of the MEMS capacitor is modeled with emphasis on the tunability range with the tuning voltage. The simulation results are presented to show the performance of RF VCO circuit with the MEMS tunable capacitor, which has a high-Q of about 60 at 1 GHZ and low insertion loss of -1dB at 40 GHz.

  4. Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator

    DEFF Research Database (Denmark)

    Tuan Vu, Cao; Wisland, Dag T.; Lande, Tor Sverre

    A low-voltage, low-power, and wide-tuning-range VCO which converts an analog input voltage to phase information for a frequency ΔΣ modulator is proposed in this paper. The VCO is based on a differential ring oscillator, which is improved with modified symmetric load and a positive feedback...... in the differential delay cells, a new bias circuit and a full-swing amplifier. The proposed VCO operating with two stages at a power supply voltage of 0.6 V can achieve wide tuning-range and low power consumption of 176.892 uW. The new VCO has a good linearity reducing harmonic distortion for frequency ΔΣ modulator...

  5. FGMOS Based Voltage-Controlled Grounded Resistor

    Directory of Open Access Journals (Sweden)

    R. Pandey

    2010-09-01

    Full Text Available This paper proposes a new floating gate MOSFET (FGMOS based voltage-controlled grounded resistor. In the proposed circuit FGMOS operating in the ohmic region is linearized by another conventional MOSFET operating in the saturation region. The major advantages of FGMOS based voltage-controlled grounded resistor (FGVCGR are simplicity, low total harmonic distortion (THD, and low power consumption. A simple application of this FGVCGR as a tunable high-pass filter is also suggested. The proposed circuits operate at the supply voltages of +/-0.75 V. The circuits are designed and simulated using SPICE in 0.25-µm CMOS technology. The simulation results of FGVCGR demonstrate a THD of 0.28% for the input signal 0.32 Vpp at 45 kHz, and a maximum power consumption of 254 µW.

  6. Analysis and Design of a 1.8-GHz CMOS LC Quadrature VCO

    DEFF Research Database (Denmark)

    Andreani, Pietro; Bonfanti, A.; Romanò, L.

    2002-01-01

    This paper presents a quadrature voltage-controlled oscillator (QVCO) based on the coupling of two LC-tank VCOs. A simplified theoretical analysis for the oscillation frequency and phase noise displayed by the QVCO in the 1/f3 region is developed, and good agreement is found between theory...

  7. Piezo Voltage Controlled Planar Hall Effect Devices

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  8. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  9. Voltage-controlled nanoscale reconfigurable magnonic crystal

    Science.gov (United States)

    Wang, Qi; Chumak, Andrii V.; Jin, Lichuan; Zhang, Huaiwu; Hillebrands, Burkard; Zhong, Zhiyong

    2017-04-01

    A nanoscale reconfigurable magnonic crystal is designed using voltage-controlled perpendicular magnetic anisotropy (PMA) in ferromagnetic-dielectric heterostructures. A periodic array of gate metallic strips is placed on top of a MgO/Co structure in order to apply a periodic electric field and to modify the PMA in Co. It is numerically demonstrated that the introduction of PMA, which can be realized experimentally via applying a voltage, modifies the spin-wave propagation and leads to the formation of band gaps in the spin-wave spectrum. The band gaps can be controlled, i.e., it is possible to switch band gaps on and off within a few tens of nanoseconds. The width and the center frequency of the band gaps are defined by the applied voltage. Finally, it is shown that the introduction of PMA to selected, rather than to all gate strips allows for a predefined modification of the band-gap spectra. The proposed voltage-controlled reconfigurable magnonic crystal opens a way to low power consumption magnonic applications.

  10. Influence of Wind Plant Ancillary Voltage Control on System Small Signal Stability

    DEFF Research Database (Denmark)

    Su, Chi; Chen, Zhe

    2012-01-01

    As a common tendency, large-scale wind farms are increasingly connected to the transmission system of modern power grids. This introduces some new challenges to the connected power systems, and the transmission system operators (TSOs) have to put some new requirements as part of the grid codes...... on the integration of wind farms. One common requirement to wind farms is the function of system voltage control which can be implemented in the grid-side convertor controller of a variable speed wind turbine. This ancillary voltage control provided by wind farms could have some influence on the system small signal...... stability. This paper implements an ancillary voltage control strategy on a direct-drive-full-convertor-based wind farm and studies its influence on the damping ratio values of the dominant oscillation mode within the connected power system. All the calculations and simulations are conducted in DIg...

  11. 324GHz CMOS VCO Using Linear Superimposition Technique

    Science.gov (United States)

    Daquan, Huang; LaRocca, Tim R.; Samoska, Lorene A; Fung, Andy; Chang, Frank

    2007-01-01

    Terahertz (frequencies ranged from 300GHz to 3THz) imaging and spectroscopic systems have drawn increasing attention recently due to their unique capabilities in detecting and possibly analyzing concealed objects. The generation of terahertz signals is nonetheless nontrivial and traditionally accomplished by using either free-electron radiation, optical lasers, Gunn diodes or fundamental oscillation by using III-V based HBT/HEMT technology[1-3]... We have substantially extended the operation range of deep-scaled CMOS by using a linear superimposition method, in which we have realized a 324GHz VCO in 90nm digital CMOS with 4GHz tuning range under 1V supply voltage. This may also pave the way for ultra-high data rate wireless communications beyond that of IEEE 802.15.3c and reach data rates comparable to that of fiber optical communications, such as OC768 (40Gbps) and beyond.

  12. One way Doppler Extractor. Volume 2: Digital VCO technique

    Science.gov (United States)

    Nossen, E. J.; Starner, E. R.

    1974-01-01

    A feasibility analysis and trade-offs for a one-way Doppler extractor using digital VCO techniques is presented. The method of Doppler measurement involves the use of a digital phase lock loop; once this loop is locked to the incoming signal, the precise frequency and hence the Doppler component can be determined directly from the contents of the digital control register. The only serious error source is due to internally generated noise. Techniques are presented for minimizing this error source and achieving an accuracy of 0.01 Hz in a one second averaging period. A number of digitally controlled oscillators were analyzed from a performance and complexity point of view. The most promising technique uses an arithmetic synthesizer as a digital waveform generator.

  13. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  14. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  15. Manual del McVCO 1999

    Science.gov (United States)

    McChesney, P.J.

    1999-01-01

    El McVCO es un generador de frecuencias basado en un microcontrolador que reemplaza al oscilador controlado por voltaje (VCO) utilizado en telemetría analógica de datos sísmicas. Acepta señales de baja potencia desde un sismómetro y produce una señal subportadora modulada en frecuencia adecuada para enlaces telefónicos o vía radio a un lugar remoto de recolección de datos. La frecuencia de la subportadora y la ganancia pueden ser seleccionadas mediante un interruptor. Tiene la opción de poder operar con dos canales para la observación con ganancia alta y baja. El McVCO fue diseñado con el propósito de mejorar la telemetría analógica de las señales dentro de la Pacific Northwest Seismograph Network (PNSN) (Red Sismográfica del Noroeste del Pacífico). Su desarrollo recibió el respaldo del Programa de Geofísica de la Universidad de Washington y del "Volcano Hazards and Earthquake Hazards programs of the United States Geological Survey (USGS) (Programa de Investigaciones de Riesgos Volcánicos y Programa de Investigaciones de Riesgos Sísmicos de los EEUU). Cientos de instrumentos se han construido e instalado. Además de utilizarlo el PNSN, el McVCO es usado por el Observatorio Vulcanológico de Alaska para monitorear los volcanes aleutianos y por el USGS Volcano Disaster Assistance Program (Programa de Ayuda en las Catástrofes Volcánicas del USGS) para responder a crisis volcánicas en otros países. Este manual cubre el funcionamiento del McVCO, es una referencia técnica para aquellos que necesitan saber con más detalle cómo funciona el McVCO, y cubre una serie de temas que requieren un trato explícito o que derivan del despliegue del instrumento.

  16. Field analysis and CAD millimeter wave VCO

    Science.gov (United States)

    Jiang, Xiao-Hong; Hong, Wei

    1992-12-01

    In this paper, the CAD of millimeter wave VCO is investigated based on a frequency-domain harmonic balance technique, where the external-circuit mutual impedances looking outside from two active devices are calculated in terms of a rigorous definition and a mixed technique of modes expansion, Galerkin method and collocation method. The CAD results are in agreement with the experimental results, which shows the raliability of the presented model and optimisation.

  17. Variable Rail Voltage Control of a Brushless DC (BLDC) Motor

    Science.gov (United States)

    2013-01-01

    Variable Rail Voltage Control of a Brushless DC (BLDC) Motor by Yuan Chen, Joseph Conroy, and William Nothwang ARL-TR-6308 January 2013...TR-6308 January 2013 Variable Rail Voltage Control of a Brushless DC (BLDC) Motor Yuan Chen, Joseph Conroy, and William Nothwang Sensors...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Variable Rail Voltage Control of a Brushless DC (BLDC) Motor 5a. CONTRACT NUMBER 5b. GRANT

  18. Adaptive Voltage Control Strategy for Variable-Speed Wind Turbine Connected to a Weak Network

    DEFF Research Database (Denmark)

    Abulanwar, Elsayed; Hu, Weihao; Chen, Zhe

    2016-01-01

    Significant voltage fluctuations and power quality issues pose considerable constraints on the efficient integration of remotely located wind turbines into weak networks. Besides, 3p oscillations arising from the wind shear and tower shadow effects induce further voltage perturbations during...... continuous operation. This study investigates and analyses the repercussions raised by integrating a doubly-fed induction generator wind turbine into an ac network of different parameters and very weak conditions. An adaptive voltage control (AVC) strategy is proposed to retain voltage constancy...

  19. A Fully Integrated Materials Framework for Enabling the Wireless Detection of Micro-defects in Aging and Battle-worn Structures

    Science.gov (United States)

    2012-05-01

    controlled oscillator ( VCO ) would drive an ultrasonic, piezoelectric transducer (XDCR), which would send acoustic waves throughout a monitored structure...receiving UD ultrasonic detector UV ultraviolet VCO voltage controlled oscillator XDCR piezoelectric transducer 25 No. of Copies

  20. 47.8 GHz InPHBT quadrature VCO with 22% tuning range

    DEFF Research Database (Denmark)

    Hadziabdic, Dzenan; Johansen, Tom Keinicke; Krozer, Viktor;

    2007-01-01

    A 38-47.8 GHz quadrature voltage controlled oscillator (QVCO) in InP HBT technology is presented. The measured output power is - 15 dBm. The simulated phase noise ranges from -84 to -86 dBc/Hz at 1 MHz offset. It is believed that this is the first millimetre-wavc QVCO implemented in InP HBT techn...

  1. DFIG turbine representation for small signal voltage control studies

    DEFF Research Database (Denmark)

    Garcia, Jorge Martinez; Kjær, Philip Carne; Teodorescu, Remus

    2010-01-01

    This paper addresses the representation of a wind power plant, based on wound rotor asynchronous generators, with a centralized voltage controller, by an equivalent transfer function, valid for small signal voltage control studies. This representation allows to investigate the influence of the ce...

  2. Resonance analysis in parallel voltage-controlled Distributed Generation inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Blaabjerg, Frede; Chen, Zhe

    2013-01-01

    Thanks to the fast responses of the inner voltage and current control loops, the dynamic behaviors of parallel voltage-controlled Distributed Generation (DG) inverters not only relies on the stability of load sharing among them, but subjects to the interactions between the voltage control loops o...

  3. Performance Characteristics of an Armature Voltage Controlled D.C. ...

    African Journals Online (AJOL)

    Performance Characteristics of an Armature Voltage Controlled D.C. Motor. ... the performance characteristics of a test motor are obtained by digital computer analysis. ... speed regulation and response characteristics for the d. c. drive system.

  4. Pembuatan Dan Evaluasi Secara In Vitro Emulsi Virgin Coconut Oil (Vco) Menggunakan Emulgator Tween 80 Dan Gom Arab

    OpenAIRE

    Silaban, Rutlin Valentina

    2015-01-01

    Background: Currently virgin coconut oil (VCO) is consumed orally as a functional food or a supplement but the VCO has a bad taste so that less acceptable by consumers. Therefore, it is necessary to formulate VCO into an emulsion that is more acceptable by consumers. Objective: The objective of this study was to prepared VCO and VCO emulsion. Methods: Preparation of VCO was conducted by fermentation using microbial yeast tempe (Rhizopus oryzae). The VCO produced was tested for water co...

  5. Analysis of VCO based noise shaping ADCs linearized by PWM modulation

    OpenAIRE

    Hernandez, Luis; Prefasi, , Enrique; Paton , Susana; Rombouts, Pieter

    2012-01-01

    Nonlinearity is one of the main problems associated with VCO based noise shaping ADCs. Their open loop architecture does not permit correction of the nonlinear voltage to frequency response of the VCO by feedback. Recently, linearization of a VCO ADC by Pulse Width Modulation (PWM) precoding has been proposed. Here, the input signal is encoded by a PWM modulator to drive the VCO with a 2-level signal, thus eliminating the nonlinearity of the VCO. This paper analyzes the remaining inherent dis...

  6. A VCO Based on LTCC Technology%基于LTCC技术的VCO研制

    Institute of Scientific and Technical Information of China (English)

    温艳兵; 徐彩红; 王红梅

    2012-01-01

      VCO is widely used in the field of communication, radar and test equipment, but the broadband tuning and miniaturization has been a bottleneck of VCO design. this paper describes the design and implementation of a microwave oscillator based on low-temperature co-fired ceramic(LTCC)technology. The models of embedded inductors which were helpful matching circuit were established by single circuit configuration and using the special microwave circuits design software(AWR)to analyze this method. The output frequency of the LTCC VCO is 1.5~2.3GHz, phase noise was-106 dBc/Hz@100kHz, output power was 13dBm, the outline dimensions were 6.9mm×6.9 mm×1.2mm,which were far less than the traditional VCO, accommodating with the miniature tendency.%  压控振荡器(VCO)在通信、雷达、测试仪器等领域中的应用非常广泛,但宽带调谐、小型化一直是VCO的设计瓶颈.文章描述了基于一种低温共烧陶瓷(LTCC)技术的微波振荡器的设计和制作,建立内埋式电感模型,并通过专用微波电路设计软件(AWR)对VCO电路进行分析,调整VCO匹配电路.测试结果表明,VCO输出频点为1.5~2.3GHz,输出相位噪声为-106dBc/Hz@100kHz,输出功率为13dBm.外形尺寸为6.9 mm×6.9 mm×1.2mm,远小于传统VCO体积,适应系统小型化的趋势.

  7. A computational model as neurodecoder based on synchronous oscillation in the visual cortex.

    Science.gov (United States)

    Songnian, Zhao; Xiaoyun, Xiong; Guozheng, Yao; Zhi, Fu

    2003-10-01

    Based on synchronized responses of neuronal populations in the visual cortex to external stimuli, we proposed a computational model consisting primarily of a neuronal phase-locked loop (NPLL) and multiscaled operator. The former reveals the function of synchronous oscillations in the visual cortex. Regardless of which of these patterns of the spike trains may be an average firing-rate code, a spike-timing code, or a rate-time code, the NPLL can decode original visual information from neuronal spike trains modulated with patterns of external stimuli, because a voltage-controlled oscillator (VCO), which is included in the NPLL, can precisely track neuronal spike trains and instantaneous variations, that is, VCO can make a copy of an external stimulus pattern. The latter, however, describes multi-scaled properties of visual information processing, but not merely edge and contour detection. In this study, in which we combined NPLL with a multiscaled operator and maximum likelihood estimation, we proved that the model, as a neurodecoder, implements optimum algorithm decoding visual information from neuronal spike trains at the system level. At the same time, the model also obtains increasingly important supports, which come from a series of experimental results of neurobiology on stimulus-specific neuronal oscillations or synchronized responses of the neuronal population in the visual cortex. In addition, the problem of how to describe visual acuity and multiresolution of vision by wavelet transform is also discussed. The results indicate that the model provides a deeper understanding of the role of synchronized responses in decoding visual information.

  8. Development of a Receiver Processor For UAV Video Signal Acquisition and Tracking Using Digital Phased Array Antenna

    Science.gov (United States)

    2010-09-01

    Unites States of America USAF Unites States Air Force USB Universal Serial Bus VCO Voltage Controlled Oscillator VI Virtual Instrument xx THIS...voltage-controlled oscillator ( VCO ) and the signal at the input. This error voltage is fed back to the input of the VCO . This process is repeated...continuously so that the VCO can keep track of the frequency changes in the input signal. The demodulated information signal can be obtained from the

  9. Design optimizations of phase noise, power consumption and frequency tuning for VCO

    Science.gov (United States)

    Nan, Chen; Shengxi, Diao; Lu, Huang; Xuefei, Bai; Fujiang, Lin

    2013-09-01

    To meet the requirements of the low power Zigbee system, VCO design optimizations of phase noise, power consumption and frequency tuning are discussed in this paper. Both flicker noise of tail bias transistors and up-conversion of flicker noise from cross-coupled pair are reduced by improved self-switched biasing technology, leading to low close-in phase noise. Low power is achieved by low supply voltage and triode region biasing. To linearly tune the frequency and get constant gain, distributed varactor structure is adopted. The proposed VCO is fabricated in SMIC 0.18-μm CMOS process. The measured linear tuning range is from 2.38 to 2.61 GHz. The oscillator exhibits low phase noise of -77.5 dBc/Hz and -122.8 dBc/Hz at 10 kHz and 1 MHz offset, respectively, at 2.55 GHz oscillation frequency while dissipating 2.7 mA from 1.2 V supply voltage, which well meet design specifications.

  10. Contribution of variable-speed wind turbines to voltage control

    Energy Technology Data Exchange (ETDEWEB)

    Ledesma, P.; Usaola, J.

    2003-07-01

    Variable speed, grid connected, wind turbines open new possibilities for voltage control, because they use electronic converters, which may regulate the reactive power interchange with the grid. This paper proposes two voltage control schemes for variable speed wind turbines with double-fed induction generator. The first scheme acts on the wind-turbine power factor, while the latter acts directly on the converter current. Advantages and draw backs of both techniques are discussed. Both control techniques have been tested by simulations of a base case, which represent a synchronous generator, a wind farm and a local load, and several disturbances such as the loss of compensator capacitors. (author)

  11. Linearity of bulk-controlled inverter ring VCO in weak and strong inversion

    DEFF Research Database (Denmark)

    Wismar, Ulrik Sørensen; Wisland, D.; Andreani, Pietro

    2007-01-01

    In this paper linearity of frequency modulation in voltage controlled inverter ring oscillators for non feedback sigma delta converter applications is studied. The linearity is studied through theoretical models of the oscillator operating at supply voltages above and below the threshold voltage...... of a transistor, bringing the transistors in respectively strong and weak inversion. The theoretical results are tested with more advanced models through spectreRF simulations. A soft rail approach implemented to improve linearity in weak inversion is proposed and demonstrated. The influence from voltage noise...

  12. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten;

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap-abl...

  13. A Jitter Less VCO Model in PLL for EMTP Simulation

    Science.gov (United States)

    Funaki, Tsuyoshi; Hikihara, Takashi

    PLL is used to synchronize the phase of an inverter AC output with that of an utility AC. The dynamic PLL behavior must be accurately simulated for it governs the control performance of an inverter. The VCO part of a PLL conventionally consists of an integrator, which is reset at the instant when it exceeds 2π. A numerical simulation, such as an EMTP simulation, with a fixed time step calculation cannot detect these accurate reset timings. This inconsistency in reset timing induces a phase jitter. The phase error, due to jitter, becomes a severe problem when a large time step is employed to simulate long period phenomena, and the inverter is modeled by the state-space averaging method. This paper proposes a jitter less VCO model for EMTP simulation. The phase jitter of the proposed VCO model is completely suppressed, regardless of the time step length. The improvements are confirmed through EMTP simulations.

  14. Proven procedures guide cavity VCO design

    Science.gov (United States)

    Lefrak, F.

    1981-05-01

    The design of a high performance voltage-tuned cavity oscillator is discussed. The circuit is to be modeled with an equivalent inductance and capacitance. Close attention is to be given to the influence of cavity loading. Center frequency and impedance are computed on the basis of the model's L and C values. The last step is particularly important, since the size of a cavity-based oscillator, such as the Gunn/varactor version is directly related to operating frequency. Attention is given to the parallel L-C circuit representing the cavity, parameter relations concerning the height, higher-order TE modes, and effects of post inductance. The basic oscillator consists of a hollow cavity with metal walls, and diodes mounted on posts.

  15. Automatic Voltage Control (AVC) of Danish Transmission System - Concept design

    DEFF Research Database (Denmark)

    Qin, Nan; Abildgaard, Hans; Lund, P.

    2014-01-01

    , objectives, constraints, algorithms for optimal power flow and some special functions in particular systems, which inspires the concept design of a Danish AVC system to address the future challenges of voltage control. In the concept, the Danish AVC design is based on a centralized control scheme. All....... Another consequence is the public way of generally thinking green which have led to a national decision of undergrounding not only all of the Danish distribution system but also the future transmission system. These issues initiate the infrastructure constructions of the transmission system i.e. a large...... the substation loses the telecommunications to the control center. RPCs will be integrated to the AVC system as normative regulators in the later stage. Distributed generation units can be organized as virtual power plants and participate in voltage control at transmission level. Energinet.dk as the Danish TSO...

  16. Automatic Voltage Control (AVC) System under Uncertainty from Wind Power

    DEFF Research Database (Denmark)

    Qin, Nan; Abildgaard, Hans; Flynn, Damian

    2016-01-01

    An automatic voltage control (AVC) system maintains the voltage profile of a power system in an acceptable range and minimizes the operational cost by coordinating the regulation of controllable components. Typically, all of the parameters in the optimization problem are assumed to be certain...... and constant in the decision making process. However, for high shares of wind power, uncertainty in the decision process due to wind power variability may result in an infeasible AVC solution. This paper proposes a voltage control approach which considers the voltage uncertainty from wind power productions....... The proposed method improves the performance and the robustness of a scenario based approach by estimating the potential voltage variations due to fluctuating wind power production, and introduces a voltage margin to protect the decision against uncertainty for each scenario. The effectiveness of the proposed...

  17. Analytical design of a 0.5V 5GHz CMOS LC-VCO

    OpenAIRE

    Yamashita, Fumiaki; Matsuoka, Toshimasa; Kihara, Takao; Takobe, Isao; Park, Hae-Ju; Taniguchi, Kenji

    2009-01-01

    A low-voltage complementary cross-coupled differential LC-VCO was investigated using simple modeling. The bias-controllability of the VCO provides a simple design for low-voltage operation. An analytical design approach realized a 5GHz VCO under a 0.5V supply voltage using a 90-nm digital CMOS process.

  18. Voltage controlled optics of a monolayer semiconductor quantum emitter

    Science.gov (United States)

    Chakraborty, Chitraleema; Goodfellow, Kenneth; Kinnischtzke, Laura; Vamivakas, Nick; University of Rochester Team

    2015-03-01

    Two-dimensional atomically thin materials are being actively investigated for next generation optoelectronic devices. Particularly exciting are transition metal dichalcogenides (TMDC) since these materials exhibit a band gap, and support valley specific exciton mediated optical transitions. In this work we report the observation of single photon emission in the TMDC tungsten diselenide. We present magneto-optical spectroscopy results and demonstrate voltage controlled photoluminescence of these localized quantum emitters.

  19. Doppler extraction with a digital VCO

    Science.gov (United States)

    Starner, E. R.; Nossen, E. J.

    1977-01-01

    Digitally controlled oscillator in phased-locked loop may be useful for data communications systems, or may be modified to serve as information extraction component of microwave or optical system for collision avoidance or automatic braking. Instrument is frequency-synthesizing device with output specified precisely by digital number programmed into frequency register.

  20. Synthetic Space Vector Modulation

    Science.gov (United States)

    2013-06-01

    Modulation RF Radio Frequency SVM Space Vector Modulation VCO Voltage Controlled Oscillator VSI Voltage Source Inverter xvi THIS PAGE...examining the literature, an NE566 voltage controlled oscillator ( VCO ) chip as seen in Figure 10 was used to design a circuit that produced the

  1. A 90nm, Low Power VCO with Reduced KVCO and Sub−band Spacing Variation

    OpenAIRE

    Collins, Diarmuid; Keady, Aidan; Szczepkowski, Grzegorz; Farrell, Ronan

    2011-01-01

    In this paper we present the design of a low power VCO with reduced variations in VCO gain (KVCO) and subband spacing resolution (fres). The proposed VCO is designed using a 90nm CMOS process to cover a tuning range of 23%. Variations in KVCO and fres are reduced by factors of 6 and 17 respectively over a conventional sub-banded VCO, designed using the same process, to meet the same tuning range. This makes the proposed VCO more suited to stable PLL operation with its ...

  2. Voltage controlled modification of flux closure domains in planar magnetic structures for microwave applications

    Energy Technology Data Exchange (ETDEWEB)

    Parkes, D. E.; Beardsley, R.; Edmonds, K. W.; Campion, R. P.; Gallagher, B. L.; Rushforth, A. W., E-mail: Stuart.Cavill@york.ac.uk, E-mail: Andrew.Rushforth@nottingham.ac.uk [School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD (United Kingdom); Bowe, S. [School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD (United Kingdom); Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Isakov, I.; Warburton, P. A. [London Centre of Nanotechnology, University College London, London WC1H 0AH (United Kingdom); Cavill, S. A., E-mail: Stuart.Cavill@york.ac.uk, E-mail: Andrew.Rushforth@nottingham.ac.uk [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Diamond Light Source, Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2014-08-11

    Voltage controlled modification of the magnetocrystalline anisotropy in a hybrid piezoelectric/ferromagnet device has been studied using Photoemission Electron Microscopy with X-ray magnetic circular dichroism as the contrast mechanism. The experimental results demonstrate that the large magnetostriction of the epitaxial Fe{sub 81}Ga{sub 19} layer enables significant modification of the domain pattern in laterally confined disc structures. In addition, micromagnetic simulations demonstrate that the strain induced modification of the magnetic anisotropy allows for voltage tuneability of the natural resonance of both the confined spin wave modes and the vortex motion. These results demonstrate the possibility for using voltage induced strain in low-power voltage tuneable magnetic microwave oscillators.

  3. Design of a Novel Current Balanced Voltage Controlled Delay Element

    Directory of Open Access Journals (Sweden)

    Pooja Saxena

    2014-04-01

    Full Text Available This paper presents a design of fast voltage controlled delay element based on modified version of low noise Current Balanced Logic (CBL. This delay element provides identical rising and falling edge delays controlled by the single control voltage. The post layout tunable delay range is from 140 ps to 800 ps over control voltage range of 0 to 2.1 V. An analysis for the delay element is also presented, which is in agreement with the simulated delays. A Delay Lock Loop (DLL is designed using this delay element to verify its performance.

  4. Dynamic Performance of Grid Converters using Adaptive DC Voltage Control

    DEFF Research Database (Denmark)

    Trintis, Ionut; Sun, Bo; Guerrero, Josep M.;

    2014-01-01

    This paper investigates a controller that ensures minimum operating dc-link voltage of a back-to-back converter system. The dc-link voltage adapts its reference based on the system state, reference given by an outer loop to the dc-link voltage controller. The operating dc-link voltage should...... be kept as low as possible to increase the power conversion efficiency and increase the reliability of converters. The dynamic performance of the proposed controller is investigated by simulations and experiments....

  5. Transition Frequencies and Negative Resistance of Inductively Terminated CMOS Buffer Cell and Application in MMW LC VCO

    Directory of Open Access Journals (Sweden)

    S. M. Rezaul Hasan

    2010-01-01

    looking into the source of the buffer cell changes sign. Possible limiting frequencies of oscillation are determined based on resonators formed by a grounded gate inductor and a parasitic capacitance at the gate of the negative resistance buffer cell. The range of frequencies of oscillation of this negative resistance buffer cell for variations in the different circuit parameters/elements is explored. Following this, a millimeter wave (MMW oscillator is simulated using the IBM 130 nm CMOS process technology which can operate at 70 GHz. High-frequency MOSFET model was used for these simulations. The cell had an extremely low power dissipation of under 3 mW. Extensive Monte Carlo simulations were carried out for manufacturability analysis considering up to 50% variation in process and geometrical parameters, supply voltage, and ambient temperature. Noise analysis and a simulated estimate of the phase noise in an MMW LC VCO application is also reported.

  6. Design and Analysis of a Slope Voltage Control for a DFIG Wind Power Plant

    DEFF Research Database (Denmark)

    Martínez, J.; Kjær, P. C.; Rodriguez, Pedro

    2012-01-01

    This paper addresses a detailed design of a wind power plant and turbine slope voltage control in the presence of communication delays for a wide short-circuit ratio range operation. The implemented voltage control scheme is based upon the secondary voltage control concept, which offers fast...

  7. Voltage-controlled domain wall traps in ferromagnetic nanowires

    Science.gov (United States)

    Bauer, Uwe; Emori, Satoru; Beach, Geoffrey S. D.

    2013-06-01

    Electrical control of magnetism has the potential to bring about revolutionary new spintronic devices, many of which rely on efficient manipulation of magnetic domain walls in ferromagnetic nanowires. Recently, it has been shown that voltage-induced charge accumulation at a metal-oxide interface can influence domain wall motion in ultrathin metallic ferromagnets, but the effects have been relatively modest and limited to the slow, thermally activated regime. Here we show that a voltage can generate non-volatile switching of magnetic properties at the nanoscale by modulating interfacial chemistry rather than charge density. Using a solid-state ionic conductor as a gate dielectric, we generate unprecedentedly strong voltage-controlled domain wall traps that function as non-volatile, electrically programmable and switchable pinning sites. Pinning strengths of at least 650 Oe can be readily achieved, enough to bring to a standstill domain walls travelling at speeds of at least ~20 m s-1. We exploit this new magneto-ionic effect to demonstrate a prototype non-volatile memory device in which voltage-controlled domain wall traps facilitate electrical bit selection in a magnetic nanowire register.

  8. Advanced on-chip divider for monolithic microwave VCO's

    Science.gov (United States)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  9. Advanced on-chip divider for monolithic microwave VCO's

    Science.gov (United States)

    Peterson, Weddell C.

    1989-05-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  10. A low-phase-noise wide-band CMOS quadrature VCO for multi-standard RF front-ends

    DEFF Research Database (Denmark)

    Fard, Ali; Andreani, Pietro

    2005-01-01

    A low phase noise CMOS LC quadrature VCO (QVCO) with a wide frequency range of 3.6-5.6 GHz, designed in a standard 0.18 μm process for multi-standard front-ends, is presented. A significant advantage of the topology is the larger oscillation amplitude when compared to other conventional QVCO...... structures. The QVCO is compared to a double cross-coupled LC-tank differential oscillator, both in theory and experiments, for evaluation of its phase noise, providing a good insight into its performance. The measured data displays up to 2 dBc/Hz lower phase noise in the 1/f2 region for the QVCO, when...... consuming twice the current of the differential VCO, based on an identical LC-tank. Experimental results on the QVCO show a phase noise level of -127.5 dBc/Hz at 3 MHz offset from a 5.6 GHz carrier while dissipating 8 mA of current, resulting in a figure of merit of 181.3 dBc/Hz....

  11. Voltage controlled resistor using quasi-floating-gate MOSFETs

    Directory of Open Access Journals (Sweden)

    Susheel Sharma

    2013-01-01

    Full Text Available A voltage controlled resistor (VCR using quasi-floating-gate MOSFETs (QFGMOS suitable for low voltage applications is presented. The performance of the VCR implemented with QFGMOS is compared with its floating-gate MOSFET (FGMOS version. It was found that QFGMOS offers better performance than FGMOS in terms of frequency response, offsets and chip area. The VCR using QFGMOS offers high bandwidth and low power dissipation and yields high value of resistance as compared to its FGMOS counterpart. The workability of the presented circuits was tested by PSpice simulations using level 3 parameters of 0.5μm CMOS technology with supply voltage of ± 0.75V. The simulations results were found to be in accordance with the theoretical predictions.

  12. Chaotic dynamics of a Chua's system with voltage controllability

    Science.gov (United States)

    Heo, Yun Seok; Jung, Jin Woo; Kim, Ji Man; Jo, Mun Kyu; Song, Han Jung

    2012-04-01

    This paper presents an integrated circuit oriented Chua's chaotic system with voltage controllability. The proposed chaotic system consists of an OTA (Operational Transconductance Amplifier)-based ground inductor, two passive capacitors, a MOS (Metal-Oxide-Semiconductor)-based active resistor and an OTA-based Chua's diode with negative nonlinearity. A SPICE (Simulation Program with Integrated Circuit Emphasis) circuit analysis using 0.5-µm CMOS (Complementary Metal-Oxide-Semiconductor) process parameters was performed for the chaotic dynamics, such as the time waveform and the attractor plot. We confirmed that the chaotic behaviors of the system could be controlled by using the gate voltage of the MOS-based active resistor. Also, various chaotic dynamics of the circuit were analyzed for various MOS sizes of the OTA in the Chua's diode.

  13. Voltage Control in Wind Power Plants with Doubly Fed Generators

    DEFF Research Database (Denmark)

    Garcia, Jorge Martinez

    In this work, the process of designing a wind power plant composed of; doubly fed induction generators, a static compensator unit, mechanically switched capacitors and on-load tap changer, for voltage control is shown. The selected control structure is based on a decentralized system, since...... supplied by the doubly fed induction generator wind turbines is overcome by installing a reactive power compensator, i.e. a static compensator unit, which is coordinated with the plant control by a specific dispatcher. This dispatcher is set according to the result of the wind power plant load flow....... To release the operation of the converters during steady-state disturbances, mechanically switched capacitors are installed in the wind power plant, which due to their characteristics, they are appropriate for permanent disturbances compensation. The mechanically switched capacitors are controlled to allow...

  14. Voltage controlled magnetism in 3d transitional metals

    Science.gov (United States)

    Wang, Weigang

    2015-03-01

    Despite having attracted much attention in multiferroic materials and diluted magnetic semiconductors, the impact of an electric field on the magnetic properties remains largely unknown in 3d transitional ferromagnets (FMs) until recent years. A great deal of effort has been focused on the voltage-controlled magnetic anisotropy (VCMA) effect where the modulation of anisotropy field is understood by the change of electron density among different d orbitals of FMs in the presence of an electric field. Here we demonstrate another approach to alter the magnetism by electrically controlling the oxidation state of the 3d FM at the FM/oxide interface. The thin FM film sandwiched between a heavy metal layer and a gate oxide can be reversibly changed from an optimally-oxidized state with a strong perpendicular magnetic anisotropy to a metallic state with an in-plane magnetic anisotropy, or to a fully-oxidized state with nearly zero magnetization, depending on the polarity and time duration of the applied electric fields. This is a voltage controlled magnetism (VCM) effect, where both the saturation magnetization and anisotropy field of the 3d FM layer can be simultaneously controlled by voltage in a non-volatile fashion. We will also discuss the impact of this VCM effect on magnetic tunnel junctions and spin Hall switching experiments. This work, in collaboration with C. Bi, Y.H. Liu, T. Newhouse-Illige, M. Xu, M. Rosales, J.W. Freeland, O. Mryasov, S. Zhang, and S.G.E. te Velthuis, was supported in part by NSF (ECCS-1310338) and by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

  15. A New Low-Power CMOS Quadrature VCO with Current Reused Structure

    Directory of Open Access Journals (Sweden)

    C. Wang

    2011-04-01

    Full Text Available A new quadrature voltage controlled oscillator (QVCO circuit topology is proposed for low-voltage and low-power applications. In the proposed circuit, two oscillators with current-reused structure are coupled to each other by two P&N-MOS pairs. In this way, low phase noise quadrature signals are generated with low-voltage and low-power. The simulation is made by Cadence in chartered 0.18 μm CMOS process. The simulation result shows that the QVCO phase noise is approximately - 117.1 dBc/Hz at 1MHz offset from 1.8 GHz operation frequency. The QVCO dissipates 1.92 mW with a 1.1 V supply voltage.

  16. A novel photonic oscillator

    Science.gov (United States)

    Yao, X. S.; Maleki, L.

    1995-01-01

    We report a novel oscillator for photonic RF systems. This oscillator is capable of generating high-frequency signals up to 70 GHz in both electrical and optical domains and is a special voltage-controlled oscillator with an optical output port. It can be used to make a phase-locked loop (PLL) and perform all functions that a PLL is capable of for photonic systems. It can be synchronized to a reference source by means of optical injection locking, electrical injection locking, and PLL. It can also be self-phase locked and self-injection locked to generate a high-stability photonic RF reference. Its applications include high-frequency reference regeneration and distribution, high-gain frequency multiplication, comb-frequecy and square-wave generation, carrier recovery, and clock recovery. We anticipate that such photonic voltage-controlled oscillators (VCOs) will be as important to photonic RF systems as electrical VCOs are to electrical RF systems.

  17. PENINGKATAN TEKNIK PENGOLAHAN BUAH KELAPA MENJADI MINYAK GORENG BERMUTU (VCO) MELALUI PROSES FERMENTASI

    OpenAIRE

    Martini Martini; S. A. Lindawati; A.A. Oka; I.A. Utami; A.A.S. Kartini

    2012-01-01

    This community activity of natural fermentation on processing origin coconut oil (VCO) was conducted at Pengembungan I, Bongkasa village,Abiansemal district, regency of Badung, Denpasar on September 28 and 29 th 2009 .The purpose of this activity was to improve the knowledge and society skill of natural fermentation on processing VCO. The methods of activity were by giving training and councelling to farmers who merged into group of Pengembungan I Bongkase about fungsional property of VCO and...

  18. 声体波谐振器压控振荡器%VCO with a Film Bulk Acoustic Resonator

    Institute of Scientific and Technical Information of China (English)

    王宗富; 郑泽渔; 杨正兵; 朱昌安; 田亚睿

    2011-01-01

    A high Q resonator and its tuning in a wide frequency range have been realized by using the BAW resonator VCO technology. The selection of MBVD model parameters of BAW resonator has been done. The selection and layout of the circuit have been arranged and the design and fabrication of. The device have been optimized. The influence due to the bonding wire between the FBAR and IC has been eliminated and the frequency adjustment has been avoided. A VCO oscillator with the central frequency of 2. 1 GHz has been developed, its output power is up to 5-10 dBm, the tuning range up to 2. 044%0, the sideband phase noise up to -143 dBc/1 Hz@l MHz.%声体波谐振器(FBAR)压控振荡器(VCO)技术探讨了高品质因数Q谐振器并实现宽频率调谐难题,完成了声体波谐振器MBVD模型参数建立、电路的选择与布局,以及最优化的设计与制作,尽量消除了FBAR与IC之间的引线产生的影响,克服了频率调整问题.研制了中心频率2.1GHz的VCO振荡器,研究结果表明,其输出功率为5~10 dBm,调谐范围为2.044‰,边带相噪为-143 dBc/1 Hz@1 MHz.

  19. Study of Voltage-Controlled Characteristics for Thermoelectric Coolers

    Science.gov (United States)

    Wang, Ning; Chen, Ming-Ming; Jia, Hong-Zhi; Jin, Tao; Xie, Ji-Long

    2017-01-01

    Based on the Peltier effect, thermoelectric coolers (TECs) have been widely used in solving thermal management issues for semiconductor devices such as semiconductor laser, charge-coupled devices and nanoelectronic circuits with hot-spots. However, performance control mechanisms especially voltage-controlled parameters for TEC still face challenges. In this paper, a standard mathematical model for multi-stage TECs is proposed with thermal resistances from both sides and performance parameters dependent on voltage. The proposed models agreed with experimental results. Compared with the available model, the relative standard deviations between the obtained equivalent thermal conductivity model and experimental results at 25°C and 50°C are decreased by 88.87% and 30.14%, respectively. Also, the relative standard deviations between the proposed thermoelectric figure of merits model and calculated results based on experiments at two different temperatures are decreased by 84.45% and 62.94%, respectively. The results provide a controllable method of thermoelectric characteristics with high accuracy, which can be employed for early thermometric performance estimation for TEC design.

  20. Write operation in MRAM with voltage controlled magnetic anisotropy

    Science.gov (United States)

    Munira, Kamaram; Pandey, Sumeet; Sandhu, Gurtej

    In non-volatile Magnetic RAM, information is saved in the bistable configuration of the free layer in a magnetic tunnel junction (MTJ). New information can be written to the free layer through magnetic induction (Toggle MRAM) or manipulation of magnetization using electric currents (Spin Transfer Torque MRAM or STT-MRAM). Both of the writing methods suffer from a shortcoming in terms of energy efficiency. This limitation on energy performance is brought about by the need for driving relatively large electrical charge currents through the devices for switching. In STT-MRAM, the nonzero voltage drop across the resistive MTJ leads to significant power dissipation. An energy efficient way to write may be with the assistance of voltage controlled magnetic anisotropy (VCMA), where voltage applied across the MTJ creates an electric field that modulates the interfacial anisotropy between the insulator and free layer. However, VCMA cannot switch the free layer completely by 180 degree rotation of magnetization. It can lower the barrier between the two stable configurations or at best, cancel the barrier, allowing 90 degree rotation. A second mechanism, spin torque or magnetic field, is needed to direct the final switching destination.

  1. Voltage Controller Saves Energy, Prolongs Life of Motors

    Science.gov (United States)

    2007-01-01

    In 1985, Power Efficiency Corporation of Las Vegas licensed NASA voltage controller technology from Marshall Space Flight Center. In the following years, Power Efficiency made patented improvements to the technology and marketed the resulting products throughout the world as the Performance Controller and the Power Efficiency energy-saving soft start. Soft start gradually introduces power to an electric motor, thus eliminating the harsh, violent mechanical stresses of having the device go from a dormant state to one of full activity; prevents it from running too hot; and increases the motor's lifetime. The product can pay for itself through the reduction in electricity consumed (according to Power Efficiency, within 3 years), depending on the duty cycle of the motor and the prevailing power rates. In many instances, the purchaser is eligible for special utility rebates for the environmental protection it provides. Common applications of Power Efficiency's soft start include mixers, grinders, granulators, conveyors, crushers, stamping presses, injection molders, elevators with MG sets, and escalators. The device has been retrofitted onto equipment at major department store chains, hotels, airports, universities, and for various manufacturers

  2. Voltage Controlled Magnetic Skyrmion Motion for Racetrack Memory.

    Science.gov (United States)

    Kang, Wang; Huang, Yangqi; Zheng, Chentian; Lv, Weifeng; Lei, Na; Zhang, Youguang; Zhang, Xichao; Zhou, Yan; Zhao, Weisheng

    2016-03-15

    Magnetic skyrmion, vortex-like swirling topologically stable spin configurations, is appealing as information carrier for future nanoelectronics, owing to the stability, small size and extremely low driving current density. One of the most promising applications of skyrmion is to build racetrack memory (RM). Compared to domain wall-based RM (DW-RM), skyrmion-based RM (Sky-RM) possesses quite a few benefits in terms of energy, density and speed etc. Until now, the fundamental behaviors, including nucleation/annihilation, motion and detection of skyrmion have been intensively investigated. However, one indispensable function, i.e., pinning/depinning of skyrmion still remains an open question and has to be addressed before applying skyrmion for RM. Furthermore, Current research mainly focuses on physical investigations, whereas the electrical design and evaluation are still lacking. In this work, we aim to promote the development of Sky-RM from fundamental physics to realistic electronics. First, we investigate the pinning/depinning characteristics of skyrmion in a nanotrack with the voltage-controlled magnetic anisotropy (VCMA) effect. Then, we propose a compact model and design framework of Sky-RM for electrical evaluation. This work completes the elementary memory functionality of Sky-RM and fills the technical gap between the physicists and electronic engineers, making a significant step forward for the development of Sky-RM.

  3. Strategies for Voltage Control and Transient Stability Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hiskens, Ian A.

    2013-09-25

    As wind generation grows, its influence on power system performance will becoming increasingly noticeable. Wind generation di ffers from traditional forms of generation in numerous ways though, motivating the need to reconsider the usual approaches to power system assessment and performance enhancement. The project has investigated the impact of wind generation on transient stability and voltage control, identifying and addressing issues at three distinct levels of the power system: 1) at the device level, the physical characteristics of wind turbine generators (WTGs) are quite unlike those of synchronous machines, 2) at the wind-farm level, the provision of reactive support is achieved through coordination of numerous dissimilar devices, rather than straightforward generator control, and 3) from a systems perspective, the location of wind-farms on the sub-transmission network, coupled with the variability inherent in their power output, can cause complex voltage control issues. The project has sought to develop a thorough understanding of the dynamic behaviour of type-3 WTGs, and in particular the WECC generic model. The behaviour of such models is governed by interactions between the continuous dynamics of state variables and discrete events associated with limits. It was shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis was proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It was shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model. In order to eliminate the anomalous behaviour revealed through this investigation, WECC has now released a new generic model for type-3 WTGs. Wind-farms typically incorporate a variety of

  4. 低功耗低相位噪声4.8GHz CMOS压控振荡器芯片设计%Design of a 4.8-GHz low power dissipation and low phase noise CMOS VCO

    Institute of Scientific and Technical Information of China (English)

    樊祥宁; 曾军; 李斌; 朱薇薇

    2011-01-01

    A 4. 8-GHz low power dissipation and low phase noise LC voltage-controlled oscillator ( VCO) for wireless sensor networks was designed and implemented based on the TSMC 0.18(xm RF CMOS process. The complementary differential negative resistance LC oscillator structure was adopted to achieve the low power dissipation. The core circuit was biased by current to reduce the sensitivity to power supply and to further decrease the power dissipation. The LC tank was carefully designed to lower the phase noise. A 3-bit switch capacitor array was adopted to provide a large tuning range without worsening the phase noise performance. The VCO was tested under a supply voltage of 1. 8 V and the results demonstrated that its whole tuning range achieved 20% , and the offset due to the variations of power supply, process corner and temperature was perfectly compensated. The phase noise of -121.68 dBc/Hz was obtained at 3 MHz offset with the carrier of 4.8GHz. The chip area is 700μm x900μm with pads and the operating current of the core circuit is only 1.5 mA.%采用TSMC 0.18μm RF CMOS工艺设计并实现了一个应用于无线传感器网络射频前端频率综合器的低功耗、低相位噪声4.8GHz电感电容压控振荡器.此振荡器的核心电路采用电流源偏置的互补差分负阻结构,降低了电路对电源电压变化的灵敏度和功耗.电感电容谐振腔采用了降低相位噪声的设计方法.在不恶化相位噪声性能的前提下,核心电路还采用3比特的开关电容阵列提高了振荡器的频率调谐范围.测试结果表明,在电源电压为1.8V时,此振荡器的频率调谐范围可达20%,可有效克服因电源波动、工艺角偏差以及温度变化等而引起的偏差;振荡频率为4.8GHz时,频偏为3MHz处的相位噪声为-121.68 dBc/Hz.芯片带焊盘面积为700μm×900μm.核心电路仅消耗1.5mA电流.

  5. Impacts on Power Factor of AC Voltage Controllers Under Non-Sinusoidal Conditions

    Directory of Open Access Journals (Sweden)

    Mukhtiar Ahmed Mahar

    2012-04-01

    Full Text Available AC-AC conversion is obtained with the help of Cyclo-converters, DC Link converters and AC Voltage Controllers. AC voltage controllers are also referred to as voltage regulators. Main issue concerned to these converters is that they generate harmonics due to periodic variable structure system. The generated harmonics create disturbances and degrade the performance of converter. The power factor of supply side is affected due to these harmonics. This paper focuses on source side power factor of ac voltage controllers under nonsinusoidal conditions. In order to observe the power factor, measurement tool of power factor and simulation model of ac voltage controller is also developed in MATLAB software.

  6. Optimasi Konsentrasi VCO dalam Mikroemulsi O/W dengan Tiga Surfaktan sebagai Pembawa Senyawa Bioaktif

    Directory of Open Access Journals (Sweden)

    IDewaGde Mayun Permana

    2015-09-01

    Full Text Available This research aims to get optimum VCO concentration in formula of O/W micro-emulsionby using three surfactant that will be used as bioactive delivery. Surfactant that is used is themixture Tween 80, Tween 20 and Span 80 by setting up HLB to 14. The phase of dispersionuses VCO while phase of continuous uses aquades of 80 percent. There are treated by changingthe ratio of VCO to surfactant, namely: 2.5, 5, 7.5 and 10 percent VCO. Randomized design isused in this research with treatment repeated twice. Results of the study shows that the optimumconcentration of VCO in O/W micro-emulsion with three surfactant is 7.5 percent

  7. Coordinated Voltage Control in Offshore HVDC Connected Cluster of Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Rather, Zakir Hussain; Rimez, Johan;

    2016-01-01

    This paper presents a coordinated voltage control scheme (CVCS) for a cluster of offshore wind power plants (OWPPs) connected to a VSC HVDC system. The primary control point of the proposed voltage control scheme is the introduced Pilot bus, which is having the highest short circuit capacity...

  8. Coordinated Voltage Control Scheme for SEIG-Based Wind Park Utilizing Substation STATCOM and ULTC Transformer

    DEFF Research Database (Denmark)

    S. El Moursi, Mohamed; Bak-Jensen, Birgitte; Abdel-Rahman, Mansour Hassan

    2011-01-01

    and optimal tracking secondary voltage control for wind parks based on self-excited induction generators which comprise STATCOM and under-load tap changer (ULTC) substation transformers. The voltage controllers for the STATCOM and ULTC transformer are coordinated and ensure the voltage support. In steady...

  9. Voltage-controlled Enzymes: The new Janus Bifrons

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Villalba-Galea

    2012-09-01

    Full Text Available The Ciona intestinalis voltage sensitive phosphatase, Ci-VSP, was the first Voltage-controlled Enzyme (VEnz proven to be under direct command of the membrane potential. The discovery of Ci-VSP conjugated voltage sensitivity and enzymatic activity in a single protein. These two facets of Ci-VSP activity have provided a unique model for studying how membrane potential is sensed by proteins and a novel mechanism for control of enzymatic activity. These facets make Ci-VSP a fascinating and versatile enzyme.Ci-VSP has a voltage sensing domain (VSD that resembles those found in voltage-gated channels (VGC. The VSD resides in the N-terminus and is formed by four putative trans-membrane segments. The fourth segment contains charged residues which are likely involved in voltage sensing. Ci-VSP produces sensing currents in response to changes in potential, within a defined range of voltages. Sensing currents are analogous to gating currents in VGC. As known, these latter proteins contain four VSDs which are entangled in a complex interaction with the pore domain –the effector domain in VGC. This complexity makes studying the basis of voltage sensing in VGC a difficult enterprise. In contrast, Ci-VSP is thought to be monomeric and its catalytic domain –the VSP’s effector domain– can be cleaved off without disrupting the basic electrical functioning of the VSD. For these reasons, VSPs are considered a great model for studying the activity of a VSD in isolation. Finally, VSPs are also phosphoinositide phosphatases. Phosphoinositides are signaling lipids found in eukaryotes and are involved in many processes, including modulation of VGC activity and regulation of cell proliferation. Understanding VSPs as VEnz has been the center of attention in recent years and several reviews has been dedicated to this area. Thus, this review will be focused instead on the other face of this true Janus Bifrons and recapitulate what is known about VSPs as electrically

  10. Electronically tunable phase locked loop oscillator

    Science.gov (United States)

    Balasis, M.; Davis, M. R.; Jackson, C. R.

    1982-02-01

    This report describes the design and development of a low noise, high power, variable oscillator incorporating a high 'Q' electronically tunable resonator as the frequency determining element. The VCO provides improved EMC performance in phase locked synthesizers which are a part of communications equipments. The oscillator combines a low noise VMOS transistor with the selectivity and out-of-band attenuation of a coaxial resonator to provide superior EMC performance. Several oscillator designs were examined and the basis for the final configuration is presented. Oscillator noise is discussed and models for analysis are explained. A brass board model was constructed and tested and the technical results are presented.

  11. The magnetic map at the V/Co interface

    Energy Technology Data Exchange (ETDEWEB)

    Carrillo-Cazares, T.A. [Esucuela de Ciencias Fisico-Matematicas, Universidad Autonoma de Sinaloa, Av. de las Americas y Blud. Universitarios, C.P. 80010, Ciudad Universitaria, Culiacan Sinaloa (Mexico); Meza-Aguilar, S. [Esucuela de Ciencias Fisico-Matematicas, Universidad Autonoma de Sinaloa, Av. de las Americas y Blud. Universitarios, C.P. 80010, Ciudad Universitaria, Culiacan Sinaloa (Mexico)]. E-mail: smeza@uas.uasnet.mx; Demangeat, C. [Institut de Physique et Chimie des Materiaux de Strasbourg, 23 rue du Loess, F-63034, Strasbourg Cedex 2 (France)

    2005-04-15

    Huttel et al. (Phys. Rev. B 68 (2003) 174405) using X-ray magnetic circular dichroism have depicted an induced magnetic moment for V atoms deposited on FCC Co(0 0 1). In the present communication, we discuss the onset of magnetic polarization of very thin V films atop Co(0 0 1) within classical density functional theory. Both local density approximation and gradient corrected approaches are used. For one V monolayer on Co(0 0 1), a ferromagnetic coupling is obtained whereas for thicker V slabs, an antiferromagnetic-like behavior is shown to be the ground state. It is clearly shown that the Co-induced polarization on V atoms is short-ranged and mainly limited to the Co-V interface. A very different magnetic behavior is observed when alloying at the V/Co interface is present.

  12. Spread-spectrum clock generation with ferroelectric capacitor-tuned VCOs.

    Science.gov (United States)

    Kabir, Abu; Kalkur, T S

    2013-08-01

    Spread-spectrum clock generation (SSCG) with barium strontium titanate (BST) ferroelectric capacitor-tuned voltage-controlled oscillator (VCO) is described. The performance of this VCO is compared with conventional diode-tuned VCOs. For a simple sinusoidal modulation waveform, a BST capacitor VCO shows uniform spread of energy over a frequency band width compared with a diode-tuned VCO with significant reduction in peak power, reducing the electromagnetic interference (EMI).

  13. Pengaruh Pemanasan Kelapa Parut dan Teknik Pengunduhan Terhadap Rendemen dan Mutu Virgin Coconut Oil (VCO

    Directory of Open Access Journals (Sweden)

    Sutardi

    2008-08-01

    Full Text Available Virgin Coconut Oil (VCO was produced from green variety ofnon-hybride coconut type. Grated coconut was heated at 500, 70°, and 90°C for 20, 30 and 40 minutes, respectively. Harvesting technique of VCO were done by conventional, utilization of stainless steel screen, and filter paper laminated stainless steel screen methods, respectively. Produced VCO was subsequently analyzed their productivity and quality parameters consisting of moisture content, acid number, free fatty acid (FFA, peroxide number, iodine number, saponification number, clearness and fatty acid profile of VCO. Statistical analysis was also conducted by using Analysis of Variance and Duncan Multiple Range Test with 5% significancy. The results showed that heating ofgrated coconut at 900C for 40 minutes produced 29.65 ±0.38% VCO, and it was the highest productivity.-Heating temperature ofgrated coconut and with any harvesting technique didn't statistitically have significant effect on productivity and quality of VCO. While, combination of heating temperature at 90°C and it was followed by harvesting technique using stainless steel screen produced the highest VCO i.e. 31.54 ± 0.58%. The best quality of VCO was characterized by 0.09 ± 0.01% moisture content, 0.20 ± 0.02 mg KOH/g oil of acid number, 0.12 ± 0.01% free fatty acid (FFA, 0.37 ± 0.01 meq/kg oil ofperoxide number, 5. 11 ± 0.01 g iod/100 g oil ofiodine number, 244. 12 ± 0.01 mg KOH/g oil saponification number and the VCO was clear and transparant. Fatty acid profile of selected VCO was dominated by medium chain fatty acid (C12:0 particularly lauric acid i.e. 50.26% and followed by 8.65% caprylic and 5,73% capric acids, respectively. "The quality parameters of VCO was able to meet the quality standard of VCO that was issued by APCC (Asia Pacific Coconut Community quality grade.

  14. Stability Analysis and Controller Synthesis for Single-Loop Voltage-Controlled VSIs

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2017-01-01

    This paper analyzes the stability of the digital single-loop voltage-controlled Voltage-Source Inverters (VSIs) using linear voltage regulators. It reveals that the phase lags caused by using the resonant controller and the time delay of digital control system can stabilize the voltage loop without...... damping of the LC-filter resonance. The stability region for the digital single-loop resonant voltage control is then identified considering the effects of the discretization methods applied to the resonant controller. An enhanced voltage control scheme with widened stability region is subsequently...

  15. Stability Analysis and Controller Synthesis for Digital Single-Loop Voltage-Controlled Inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2016-01-01

    This paper analyzes first the stability of single-loop digital voltage control scheme for the LC-filtered voltage source inverters. It turns out that the phase lag, caused by the time delay of digital control system and by the use of integral controller, can stabilize the voltage loop without...... damping of LC-filter resonance. The stability regions are then identified with alternative voltage controller synthesized. For further widening the stability region, an active damping approach is proposed and co-designed with the voltage controller in the discrete z-domain. Simulations and experimental...

  16. Wideband CMOS LC VCO design and phase noise analysis%宽带CMOS LC压控振荡器设计及相位噪声分析

    Institute of Scientific and Technical Information of China (English)

    郭雪锋; 王志功; 李智群; 唐路

    2008-01-01

    A wideband LC cross-coupled voltage controlled oscillator(VCO) is designed and realized with standard 0.18 μm complementary metal-oxide-semiconductor (CMOS) technology. Band switching capacitors are adopted to extend the frequency tuning range, and the phase noise is optimized in the design procedure. The functional relationships between the phase noise and the transistors' width-length ratios are deduced by a linear time variant (LTV) model. The theoretical optimized parameter value ranges are determined. To simplify the calculation, the working region is split into several sub-ranges according to transistor working conditions. Thus, a lot of integrations are avoided, and the phase noise function upon the design variables can be expressed as simple proportion formats. Test results show that the DC current is 8. 8 mA under a voltage supply of 1.8 V; the frequency range is 1.17 to 1.90 GHz, and the phase noise reaches -83 dBc/Hz at a 10 kHz offset from the carrier. The chip size is 1.2 mm × 0. 9 mm.%应用标准0.18 μm CMOS工艺设计并实现了宽带交叉耦合LC压控振荡器.采用开关电容阵列拓宽频率范围.设计过程中对相位噪声进行了优化.应用线性时变模型(LTV)推导出相位噪声与MOS晶体管宽长比之间的函数关系,从理论上给出相位噪声性能最优的元件参数取值范围.为简化推导过程,针对电路特点按晶体管工作状态来细分电路工作区域,从而避免了大量积分运算,以尽可能简单的比例形式得到相位噪声与设计变量间的函数关系.测试结果表明,在1.8 V电源电压下,核心电路工作电流为8.8 mA,压控振荡器的频率范围为1.17~1.90 GHz,10 kHz频偏处相位噪声达到-83 dBc/Hz.芯片面积为1.2 mm×0.9 mm.

  17. A low-phase-noise ring oscillator with coarse and fine tuning in a standard CMOS process

    Science.gov (United States)

    Haijun, Gao; Lingling, Sun; Xiaofei, Kuang; Liheng, Lou

    2012-07-01

    A low-phase-noise wideband ring oscillator with coarse and fine tuning techniques implemented in a standard 65 nm CMOS process is presented. Direct frequency modulation in the ring oscillator is analyzed and a switched capacitor array is introduced to produce the lower VCO gain required to suppress this effect. A two-dimensional high-density stacked MOM-capacitor was adopted as the switched capacitor to make the proposed ring VCO compatible with standard CMOS processes. The designed ring VCO exhibits an output frequency from 480 to 1100 MHz, resulting in a tuning range of 78%, and the measured phase noise is -120 dBc/Hz @ 1 MHz at 495 MHz output. The VCO core consumes 3.84 mW under a 1.2 V supply voltage and the corresponding FOM is -169 dBc/Hz.

  18. Smart Demand for Improving Short-term Voltage Control on Distribution Networks

    DEFF Research Database (Denmark)

    Garcia-Valle, Rodrigo; P. Da Silva, Luiz C.; Xu, Zhao

    2009-01-01

    customer integration to aid power system performance is almost inevitable. This study introduces a new type of smart demand side technology, denoted demand as voltage controlled reserve (DVR), to improve short-term voltage control, where customers are expected to play a more dynamic role to improve voltage...... control. The technology can be provided by thermostatically controlled loads as well as other types of load. This technology is proven to be effective in case of distribution systems with a large composition of induction motors, where the voltage presents a slow recovery characteristic due to deceleration...... of the motors during faults. This study presents detailed models, discussion and simulation tests to demonstrate the technical viability and effectiveness of the DVR technology for short-term voltage control....

  19. Co-ordinated voltage control of DFIG wind turbines in uninterrupted operation during grid faults

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Michalke, G.; Sørensen, Poul Ejnar

    2007-01-01

    is implemented in the power system simulation toolbox PowerFactory DIgSILENT. The DFIG wind farm ride-through capability and contribution to voltage control in the power system are assessed and discussed by means of simulations with the use of a transmission power system generic model developed and delivered......-side converter as long as it is not blocked by the protection system, otherwise the grid-side converter takes over the voltage control. Moreover, the article presents a DFIG wind farm model equipped with a grid fault protection system and the described co-ordinated voltage control. The whole DFIG wind farm model...... by the Danish Transmission System Operator Energinet.dk. The simulation results show how a DFIG wind farm equipped with voltage control can help a nearby active stall wind farm to ride through a grid fault, without implementation of any additional ride-through control strategy in the active stall wind farm....

  20. A Robust 43-GHz VCO in CMOS for OC-768 SONET Applications

    NARCIS (Netherlands)

    Wel, van der Arnoud P.; Gierink, Sander L.J.; Frye, Robert C.; Boccuzzi, Vito; Nauta, Bram

    2004-01-01

    In this paper, we present a 43-GHz LC-VCO in 0.13-/spl mu/m CMOS for use in SONET OC-768 optical networks. A tuned output buffer is used to provide 1.3 V/sub p-p/ (single-ended) into a 90-fF capacitive load as is required when the VCO is used in typical clock and data recovery (CDR) circuits. Phase

  1. A 2.3GHz LC-tank CMOS VCO with optimal phase noise performance

    DEFF Research Database (Denmark)

    Andreani, Pietro; Fard, Ali

    2006-01-01

    The phase-noise theory and design of a differential CMOS LC-tank VCO with double switch pair is presented. A formula for the minimum achievable phase noise in the 1/f2 region is derived. The 2.15 to 2.35GHz 0.3mum CMOS VCO has a phase noise of -143.9dBc/Hz at 3MHz offset and draws 4mA from a 2.5V...

  2. Mode localized MEMS transducers with voltage-controlled linear coupling

    Science.gov (United States)

    Manav, M.; Srikantha Phani, A.; Cretu, E.

    2017-05-01

    Recent studies have demonstrated mode localized resonant micro-electro-mechanical systems (MEMS) sensing devices with orders of magnitude improvement in sensitivity. Avoided crossings or eigenvalue veering is the physical mechanism exploited to achieve the enhancement in sensitivity of devices operating either in vacuum or in air. The mode localized MEMS devices are typically designed to be symmetric and use gap-varying electrostatic springs to couple motions of two or more resonators. The role of asymmetry in the design of devices and its influence on sensitivity is not fully understood. Furthermore, gap-varying electrostatic springs suffer from nonlinearities when gap variation between coupling plates becomes large due to mode localization, imposing limitations on the device performance. To address these shortcomings, this contribution has two principal objectives. The first objective is to critically assess the role of asymmetry in the device design and operation. We show, based on energy analysis, that carefully designed asymmetry in devices can lead to even higher sensitivities than reported in the literature. Our second objective is to design and implement linear, tunable, electrostatic springs, using shaped combs, which allow large vibration amplitudes of resonators thereby increasing the signal to noise ratio. We experimentally demonstrate linear electrostatic coupling in a two oscillator device. Our study suggests that a future avenue for progress in the mode localized resonant sensing technology is to combine asymmetric devices with tunable linear coupling designs.

  3. Bottom-series coupled quadrature VCO using the inductive gate voltage boosting technique

    Science.gov (United States)

    Jang, Sheng-Lyang; Chou, Li-Te

    2013-09-01

    This article presents a new low-voltage bottom-series coupled quadrature voltage-controlled oscillator (QVCO), which consists of two n-core cross-coupled VCOs with the bottom-series coupling transistors. The low-voltage operation is obtained via an inductive gate voltage boosting technique. The proposed CMOS QVCO has been implemented with the TSMC 0.18 µm CMOS technology and the die area is 0.897 × 0.767 mm2. At the supply voltage of 0.7 V, the total power consumption is 1.5 mW. The free-running frequency of the QVCO is tuneable from 3.77 to 4.12 GHz as the tuning voltage is varied from 0.0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is -123.35 dBc/Hz at the oscillation frequency of 4.12 GHz and the figure of merit of the proposed QVCO is -193.5 dBc/Hz.

  4. Association of VO2 and VCO2 rate variability with serum glucose, insulin, and glucose intolerance.

    Science.gov (United States)

    Satué-Rodríguez, Julián; Méndez, José D

    2012-08-01

    Changes in the cellular metabolism assessed by the variability of oxygen consumption (VO(2) ) and carbon dioxide production (VCO(2) ) as well as the association of serum glucose and insulin to energy spectral density (ESD) of VO(2) and VCO(2) were evaluated. Ten nonglucose intolerant and 10 glucose intolerant subjects, aged 21-70 years, were included. Glucose and insulin concentrations and VO(2) and VCO(2) records were collected every 10 min during 3 h. ESD of VO(2) and VCO(2) was estimated and associated with glucose and insulin concentrations. Statistical significance in glucose levels, insulin, and ESD of VO(2) and VCO(2) among nonglucose intolerant subjects and glucose and insulin among glucose intolerance subjects at postload glucose (PLG) state compared with basal state was found. Moreover, glucose was significantly higher in glucose intolerance subjects than nonglucose intolerant subjects for basal and PLG states. These results show an increment in ESD of VO(2) and VCO(2) at PLG state among nonglucose intolerant subjects and suggest that their measurement may be a key indicator of the variability of cellular metabolic activity and contribute to confirm disturbances in glucose metabolism.

  5. 低噪声C波段MMIC VCO

    Institute of Scientific and Technical Information of China (English)

    江兴

    2004-01-01

    <正> Hittite Microwave公司新近开发出一对GaAs/InGaP HBT MMIC压控振荡器(VCO),VCO与电阻、负阻器件、变容二极管及缓冲放大器集成,其工作频率为5.0~6.1GHz。这两种型号为HMC430LP4和HMC431LP4的VCO适用于C波段无线局域网、甚小孔径终端、点到点无线电设备等。上述两种型号的VCO无需外部元件,使用+3V单电源,耗电27mA。其封装为塑料表面安装封装。 HMC430LP4在5.0~5.5GHz、100KHz相噪偏移下的缓冲输出功率为+2dBm,相噪仅—103dBc/Hz;HMC431LP4在5.5~6.1GHz、100KHz相噪偏移下的缓冲输出功率

  6. Quasi-Optical Cavity Virtual Cathode Oscillator for Microwave Generation

    Institute of Scientific and Technical Information of China (English)

    凌根深; 陈波; 周津娟

    2003-01-01

    A new configuration of a virtual cathode oscillator(VCO),i.e.,a quasi-optical cavity VCO,is proposed for highpower microwave generation.The analysis and simulation are carried out to investigate the characteristics of this configuration.In the numerical simulation,the microwave output power of 2.93 GW is obtained with an electron beam of 610 keV in electron energy and 26.7kA in the beam current.The beam-to-microwave power efficiency is 18%.The frequency is 17.5 GHz,and the output microwave mode is TEM10.

  7. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    Directory of Open Access Journals (Sweden)

    Jong-Chan Choi

    2014-10-01

    Full Text Available Direct Current (DC microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. This paper analyzes voltage drop problems in a large DC microgrid and proposes a cooperative voltage control scheme with a distributed generator (DG and a grid connected converter (GCC. For the voltage control with DGs, their location and capacity should be considered for economic operation in the systems. Accordingly, an optimal DG allocation algorithm is proposed to minimize the capacity of a DG for voltage control in DC microgrids. The proposed methods are verified with typical load types by a simulation using MATLAB and PSCAD/EMTDC.

  8. Voltage Control Method Using Distributed Generators Based on a Multi-Agent System

    Directory of Open Access Journals (Sweden)

    Hyun-Koo Kang

    2015-12-01

    Full Text Available This paper presents a voltage control method using multiple distributed generators (DGs based on a multi-agent system framework. The output controller of each DG is represented as a DG agent, and each voltage-monitoring device is represented as a monitoring agent. These agents cooperate to accomplish voltage regulation through a coordinating agent or moderator. The moderator uses the reactive power sensitivities and margins to determine the voltage control contributions of each DG. A fuzzy inference system (FIS is employed by the moderator to manage the decision-making process. An FIS scheme is developed and optimized to enhance the efficiency of the proposed voltage control process using particle swarm optimization. A simple distribution system with four voltage-controllable DGs is modeled, and an FIS moderator is implemented to control the system. Simulated data show that the proposed voltage control process is able to maintain the system within the operating voltage limits. Furthermore, the results were similar to those obtained using optimal power flow calculations, even though little information on the power system was required and no power flow calculations were implemented.

  9. Voltage control in active, intelligent low-voltage distribution networks; Spannungshaltung in aktiven, intelligenten Niederspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Buelo, Thorsten; Mende, Denis [SMA Solar Technology AG, Niestetal (Germany); Geibel, Dominik [Fraunhofer Institut fuer Windenergie und Energiesystemtechnik (IWES), Kassel (Germany)] [and others

    2012-07-01

    This paper describes approaches for the voltage control in low-voltage distribution networks with a high share of distributed energy resources (DER). Taken into account are devices such as distribution transformers with on-load tap changer (OLTC), photovoltaic-inverters with reactive power capability and electronic voltage controllers (EVC). After a short description regarding voltage control, the devices and selected system concepts as well as the advantages and disadvantages of the different devices are described. Finally, the system-concepts are compared using the example of a real low voltage network, taking into account the possible increase of hosting capacity of the network, curtailing losses and the amount of reactive energy to be provided. (orig.)

  10. Blood cholesterol levels of hypercholesterolemic rat (Rattus norvegicus after VCO treatment

    Directory of Open Access Journals (Sweden)

    OKID PARAMA ASTIRIN

    2009-07-01

    Full Text Available Harini M, Astirin OP. 2009. Blood cholesterol levels of hypercholesterolemic rat (Rattus norvegicus after VCO treatment. Nusantara Bioscience 1: 53-58. This study aims to determine treatment effect of VCO on blood cholesterol levels in hypercholesterolemic white rat (Rattus norvegicus L.. This study used 25 male rats of Wistar strain divided into five treatment groups, namely: control, simvastatin (1.3 mL/270 g BW, cholesterol (9:1 lard, VCO 1 (1 mL/270 g BW, and VCO 2 (1.3 mL/270 g BW. Treatment was given orally. Total cholesterol, LDL and HDL cholesterol levels were measured at day 1, day 14 and day 28. Cholesterol data (total cholesterol, LDL and HDL were analyzed by Ancova and followed by contrast test at significance level of 5%.. The results showed that treatment of VCO at different doses significantly affected the decrease in blood total cholesterol, blood LDL levels, increasing blood HDL in hipercholesterolemic white rat.

  11. Kadar kolesterol darah tikus putih (Rattus norvegicus hiperkolesterolemik setelah perlakuan VCO

    Directory of Open Access Journals (Sweden)

    MARTI HARINI

    2009-11-01

    Full Text Available Harini M, Astirin OP. 2009. Kadar kolesterol darah tikus putih (Rattus norvegicushiperkolesterolemik setelah perlakuan VCO. Bioteknologi 6: 55-62. Penelitian ini bertujuan untuk mengetahui pengaruh perlakuan VCO terhadap kadar kolesterol darah tikus putih (Rattus norvegicus L. hiperkolesterolemik. Penelitian ini menggunakan 25 tikus putih jantan galur Wistar yang dikelompokkan menjadi lima kelompok perlakuan, yaitu: kontrol, simvastatin (1,3 mL/270 g BB, kolesterol (lemak babi 9:1, VCO 1 (1 mL/270 g BB, dan VCO 2 (1,3 mL/270 g BB. Perlakuan diberikan secara oral. Kadar kolesterol total, kadar LDL dan kadar HDL diukur pada hari ke-1, ke-14 dan hari ke-28. Data kadar kolesterol (kolesterol total, LDL dan HDL dianalisis dengan ANCOVA dan dilanjutkan dengan uji contrast pada taraf signifikansi 5%. Hasil penelitian menunjukkan bahwa perlakuan VCO pada berbagai dosis berpengaruh nyata terhadap penurunan kadar kolesterol total darah, kadar LDL darah dan peningkatan kadar HDL darah tikus putih (R. norvegicus hiperkolesterolemik.

  12. A low-power current self-adjusted VCO using a bottom PMOS current source

    Science.gov (United States)

    Zhixiong, Sheng; Fengqi, Yu

    2014-09-01

    This paper presents the design and implementation of a current self-adjusted VCO with low power consumption. In the proposed VCO, a bottom PMOS current source instead of a top one is adopted to decrease the tail noise. A current self-adjusted technique without additional external control signals is taken to ensure the VCO starts up in the whole band while keeping the power consumption relatively low. Meanwhile, the phase noise of the VCO at the low frequency (high Cvar) can be reduced by the technique. The circuit is implemented in 0.18 μm CMOS technology. The proposed VCO exhibits low power consumption of < 1.6 mW at a 1.5 V supply voltage and a tuning range from 11.79 to 12.53 GHz. The measured phase noise at 1 MHz offset from the frequency 11.79 GHz is -104.7 dBc/Hz, and the corresponding FOM is -184.2 dBc/Hz.

  13. PENGARUH KONSENTRASI XANTHAN GUM TERHADAP STABILITAS FISIK KRIM VIRGIN COCONUT OIL (VCO

    Directory of Open Access Journals (Sweden)

    Beti Pudyastuti

    2016-04-01

    Full Text Available Abstract: Virgin Coconut Oil (VCO is a pure oils that is extracted from fresh coconut meat at low temperatures. The formulation of VCO in cream dosage form could retain skin moisture and improve the acceptability. Xanthan gum is one of the emulsifier that used to form oil in water (O/W cream. The purpose of this research were to determine the effect of xanthan gum concentration to the physical stability of VCO cream. VCO creams were prepared by emulsifying the oil phase and the water phase with the variation of xanthan gum concentration (2.5; 2.7; 2.9; 3.1; 3.3% w/w. Observation of the physical stability of the cream includes organoleptic, emulsion type, droplets size, viscosity, spreadability, adhesion, and ratio of separation volume was conducted until 7th week, and also the freeze-thaw test for three cycles. The results showed that each formulation could produces homogeneous light brown cream with oil in water type. Increasing of xanthan gum concentration would increases viscosity of the cream so that spreadability decreases and adhesion increases during stability study. Ratio of separation volume increased after three cycles of freeze-thaw test. Cream with 3.3% w/w xanthan gum had the optimum physical stability. Keywords : VCO, O/W cream, xanthan gum, physical stability

  14. Self-focusing effect in voltage-controlled PPLN waveguide arrays

    Institute of Scientific and Technical Information of China (English)

    Yong Yang; Xuewei Deng; Huiying Lao; Xianfeng Chen

    2011-01-01

    @@ Self-focusing effect via Kerr nonlinearity is observed in periodically poled lithium niobate (PPLN) waveguide arrays formed by electro-optic effect. Voltage-control method is demonstrated to control the focusing and diffraction of light. Theoretical simulation results show good agreement with experimental results.%Self-focusing effect via Kerr nonlinearity is observed in periodically poled lithium niobate (PPLN) waveguide arrays formed by electro-optic effect. Voltage-control method is demonstrated to control the focusing and diffraction of light. Theoretical simulation results show good agreement with experimental results.

  15. Coordinated Voltage Control Scheme for SEIG-Based Wind Park Utilizing Substation STATCOM and ULTC Transformer

    DEFF Research Database (Denmark)

    S. El Moursi, Mohamed; Bak-Jensen, Birgitte; Abdel-Rahman, Mansour Hassan

    2011-01-01

    and optimal tracking secondary voltage control for wind parks based on self-excited induction generators which comprise STATCOM and under-load tap changer (ULTC) substation transformers. The voltage controllers for the STATCOM and ULTC transformer are coordinated and ensure the voltage support. In steady......-state operation, the voltage is controlled by only stepping the tap changer when the voltage is outside the deadband region of the ULTC to minimize the number of taps changes. Thus, the STATCOM will be unloaded and ready to react with higher reactive power margin during contingencies. In the paper, the effects...

  16. Voltage Control Scheme for Three Phase SVM Inverter Fed Induction Motor Drive Systems

    Directory of Open Access Journals (Sweden)

    U. SOWMMIYA

    2010-12-01

    Full Text Available This paper presents an efficient implementation scheme for the closed-loop voltage control of an induction motor incorporating ‘Space Vector Pulse Width Modulation (SVPWM‘. Voltage control is required to meet the variation in the input voltage and to regulate the output of the inverter. Space Vector Modulation (SVM is an algorithm for the control of Pulse Width Modulation (PWM. Comparative study has been made between SVM and PWM techniques. From the simulation results, SVM has reduced THD compared to pulse width modulation techniques. Thus, SVM gives better harmonic response and higher efficiency.

  17. Comparison of two voltage control strategies for a wind power plant

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Philip C.; Rodriguez, Pedro

    2011-01-01

    , it is possible to investigate the influence of the plant control gain, short circuit ratio, and time delays on the system stability, as well as the fulfillment of the design requirements. The implemented plant voltage control is based on a slope voltage controller, which calculates the references to be sent...... to the wind turbines, according to the slope gain and the difference between the reference and measured voltage at the point of connection. The results show that for a system where the time delay between the central control and the actuators is not negligible, the performance of a decentralized voltage...

  18. Multi-Stage Optimization Based Automatic Voltage Control Systems Considering Wind Power Forecasting Errors

    DEFF Research Database (Denmark)

    Qin, Nan; Bak, Claus Leth; Abildgaard, Hans

    2017-01-01

    cost and the generator reactive power output cost. The problem is formulated in a multi-stage optimal reactive power flow (MORPF) framework, solved by the nonlinear programming techniques via a rolling process. The voltage uncertainty caused by wind power forecasting errors is considered in the optimal......This paper proposes an automatic voltage control (AVC) system for power systems with limited continuous voltage control capability. The objective is to minimize the operational cost over a period, which consists of the power loss in the grid, the shunt switching cost, the transformer tap change...

  19. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... analysis, which is simple for computation and requires moderate automation and communication infrastructure. The proposed method is suitable for a hierarchical control structure where a supervisory controller has the provision to adapt the settings of local PV inverter controllers for overall system...

  20. Equivalent realisation circuit for a class of non-ideal voltage-controlled memristors

    Directory of Open Access Journals (Sweden)

    Saihu Pan

    2015-12-01

    Full Text Available In this study, an equivalent realisation circuit with off-the-shelf components and devices is proposed, which can be used to equivalently implement a class of non-ideal voltage-controlled memristors. The mathematical models of the equivalent realisation circuit with three function arithmetic circuits are built and their fingerprints are analysed by the pinched hysteresis loops with bipolar periodic voltage stimuli. The numerical simulations are easily verified by experimental measurements, which indicate that when three function arithmetic circuits are linked, the equivalent realisation circuit can realise three non-ideal voltage-controlled memristors with different non-linearities.

  1. A Power-Efficient LC Quadrature VCO for RFID, Zigbee and Bluetooth Standards

    Directory of Open Access Journals (Sweden)

    TORKZADEH, P.

    2009-10-01

    Full Text Available A multi-band CMOS LC Quadrature Voltage Control Oscillator (QVCO with minimum power consumption is developed to meet the phase noise and frequency band requirements of RFID, Zigbee and Bluetooth standards. To accomplish the multi-band receiving architecture at low power consumption, current switching technique with optimized cross-coupled transistor sizes has been used. A comprehensive analysis of small signal model for complementary architecture including transistor noise sources and their effects on output phase noise amount has been discussed. Using extracted small signal model, coupled and coupling transistor sizes for minimum power consumption and the least achievable phase noise have been optimized. Designed QVCO has been implemented using TSMC 0.18um CMOS technology operating at 1.8V supply voltage. Proposed QVCO generates two separated frequency bands of 1.65-1.85GHz and 2.4-2.5GHz with phase noise of -125dBc/Hz at frequency offset of 3MHz. The total current drawn by QVCO is 7.5mA which makes the power consumption as low as 13.5mW.

  2. Design and Testing of a Low Cost PID Controller Combined with Inverse Derivative Control Action and Its Application in Voltage Control Systems of DC Generator

    Directory of Open Access Journals (Sweden)

    Subrata CHATTOPADHYAY

    2008-01-01

    Full Text Available A single PID controller in a process control loop may suffer from high frequency oscillations without offset or low frequency oscillation with offset. An inverse derivative control action can eliminate both of these errors. In the present paper, a low cost operational amplifier based PID controller with inverse derivative control action has been described. Its transfer function has been derived and is found to be identical with the form already derived by other workers. It has been tested with a process plant analogue and implemented in the voltage control system of a DC generator. Its transfer function along with its characteristics in a process plant analogue and the load characteristics of DC generator with and without this controller have been determined experimentally and reported in this paper.

  3. A bulk-controlled ring-VCO with 1/f-noise reduction for frequency ΔΣ modulator

    DEFF Research Database (Denmark)

    Tuan Vu, CAO; Wisland, Dag T.; Lande, Tor Sverre

    The paper introduces a bulk-controlled ring-VCO with a tail transistor utilizing flicker-noise (1/f-noise) reduction techniques for a frequency-based DeltaSigma modulator (FDSM). This VCO converts an analog input voltage to phase information under various bias conditions ranging from sub...

  4. A 12 GHz low-jitter LC-VCO PLL in 130 nm CMOS

    Science.gov (United States)

    You, Y.; Chen, J.; Feng, Y.; Tang, Y.; Huang, D.; Rui, W.; Gong, D.; Liu, T.; Ye, J.

    2015-03-01

    We present a wideband low-jitter LC-VCO phase-locked loop in 130 nm CMOS technology for high speed serial link applications. The PLL covers a 5.6 GHz to 13.4 GHz frequency range by using two LC-VCO cores with an RMS jitter of 370 fs. The single event effects testing is performed with a neutron beam at Los Alamos National Laboratory and no frequency disturbance is found over the test period. The PLL consumes 50.88 mW of power under a 1.2 V power supply.

  5. Enhancement of VCO Linearity and Phase Noise by Implementing Frequency Locked Loop

    DEFF Research Database (Denmark)

    Ayranci, E; Christensen, K; Andreani, Pietro

    2007-01-01

    This paper investigates the on-chip implementation of a frequency locked loop (FLL) over a VCO that decreases the phase noise and linearizes the transfer function. Implementation of the FLL inside a PLL is also investigated and a possible application is highlighted. Design of a special kind of low...... noise frequency detector without a reference frequency (frequency-to-voltage converter), which is the most critical component of the FLL, is also presented in a 0.25 mum BiCMOS process. Linearization and approximately 15 dBc/Hz phase noise suppression is demonstrated over a moderate phase noise LC VCO...

  6. Tunable sensor response by voltage-control in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2012-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors mediates large (80% and more) voltage-controlled electromechanical amplification of the flow signal for freque

  7. Tunable sensor response by voltage-control in biomimetic hair flow sensors

    NARCIS (Netherlands)

    Droogendijk, H.; Krijnen, G.J.M.

    2012-01-01

    We report improvements in detection limit and responsivity of biomimetic hair flow sensors by electrostatic spring-softening (ESS). Applying a DC-bias voltage to our capacitive flow sensors mediates large (80% and more) voltage-controlled electro-mechanical amplification of the flow signal for frequ

  8. A New Approach to HVDC Grid Voltage Control Based on Generalized State Feedback

    DEFF Research Database (Denmark)

    Beerten, Jef; Eriksson, Robert; Van Hertem, Dirk

    2014-01-01

    In this paper, a new approach to DC voltage control in a High Voltage Direct Current (HVDC) grid is introduced. In an HVDC grid, the power sharing after a converter outage can be influenced by the droop control values. However, when relying on a local feedback signal, the DC voltage drops...

  9. A Hybrid Optimization Method for Reactive Power and Voltage Control Considering Power Loss Minimization

    DEFF Research Database (Denmark)

    Liu, Chengxi; Qin, Nan; Bak, Claus Leth;

    2015-01-01

    This paper proposes a hybrid optimization method to optimally control the voltage and reactive power with minimum power loss in transmission grid. This approach is used for the Danish automatic voltage control (AVC) system which is typically a non-linear non-convex problem mixed with both continu...

  10. Distributed voltage control coordination between renewable generation plants in MV distribution grids

    DEFF Research Database (Denmark)

    Petersen, Lennart; Iov, Florin

    2017-01-01

    This study focuses on distributed voltage control coordination between renewable generation plants in medium-voltage distribution grids (DGs). A distributed offline coordination concept has been defined in a previous publication, leading to satisfactory voltage regulation in the DG. However, here...

  11. A Communication-Less Distributed Voltage Control Strategy for a Multi-Bus AC Islanded Microgrid

    DEFF Research Database (Denmark)

    Wang, Yanbo; Tan, Yongdong; Chen, Zhe

    2014-01-01

    This paper presents a communication-less distributed voltage control strategy for a multi-bus AC islanded microgrid. First, a Kalman Filter-based network voltage estimator is proposed to obtain voltage responses without communication links in the presence of load disturbances. Then, a voltage opt...

  12. Assessment of distribution grid voltage control strategies in view of deployment

    DEFF Research Database (Denmark)

    Han, Xue; Kosek, Anna Magdalena; Bondy, Daniel Esteban Morales

    2014-01-01

    different capabilities of DERs and regulating devices to assist grid operation. However, very few of them have discussed the opportunities and barriers of deploying the control strategies in practice. This paper reviews some typical control solutions on providing voltage control services. Furthermore...

  13. Low Phase Noise SiGe Push-Push Oscillators for Millimeter Wave Frequencies

    OpenAIRE

    2008-01-01

    In this thesis low phase noise SiGe HBT monolithically integrated push-push oscillators for millimeter wave frequency generation are investigated. Nonlinear simulation methods for oscillator signal and noise analysis and device physics at high currents and high voltages are discussed. Push-push oscillators with output frequencies from 63 GHz up to 280 GHz were designed and after fabrication in an external foundry investigated experimentally. For automotive radar applications a VCO with a cent...

  14. Assessment of the operating conditions of coordinated Q-V controller within secondary voltage control system

    Directory of Open Access Journals (Sweden)

    Arnautović Dušan

    2014-01-01

    Full Text Available The paper, discusses the possibility to use coordinated Q-V controller (CQVC to perform secondary voltage control at the power plant level. The CQVC performs the coordination of the synchronous generators' (SG reactive power outputs in order to maintain the same total reactive power delivered by the steam power plant (SPP, while at the same time maintaining a constant voltage with programmed reactive droop characteristic at the SPP HV busbar. This busbar is the natural pilot node for secondary voltage control at HV level as the node with maximum power production and maximum power consumption. In addition to voltage control, the CQVC maintains the uniform allocation of reactive power reserves at all SGs in the power plant. This is accomplished by setting the reactive power of each SG at given operating point in accordance to the available reactive power of the same SG at that point. Different limitations imposed by unit's and plant equipment are superimposed on original SG operating chart (provided by the manufacturer in order to establish realistic limits of SG operation at given operating point. The CQVC facilitates: i practical implementation of secondary voltage control in power system, as it is capable of ensuring delivery of reactive power as requested by regional/voltage control while maintaining voltage at system pilot node, ii the full deployment of available reactive power of SGs which in turn contributes to system stability, iii assessment of the reactive power impact/contribution of each generator in providing voltage control as ancillary service. Furthermore, it is also possible to use CQVC to pricing reactive power production cost at each SG involved and to design reactive power bidding structure for transmission network devices by using recorded data. Practical exploitation experience acquired during CQVC continuous operation for over two years enabled implementation of the optimal setting of reference voltage and droop on daily

  15. Solid State Research

    Science.gov (United States)

    2007-11-02

    demonstrated the advantages of using predistortion , or compensation, to linearize a microwave voltage-controlled oscillator (VCO) for compressive...receiver SLO applications by using polynomial fitting to a static VCO tuning characteristic and applying the predistortion in a fixed analog fashion [2

  16. The Lunar Laser Communications Demonstration

    Science.gov (United States)

    2011-04-05

    clocks at the LLGT. A 5-GHz voltage-controlled oscillator ( VCO ) is used to generate the recovered 311-MHz slot clock in the LLST uplink receiver. This...same VCO is used to generate the 5-GHz slot clock for the optical downlink, thereby ensuring that the uplink and downlink slot clocks are phase

  17. A physical model of a CMOS varactor with high capacitance tuning range and its application to simulate integrated VCOs

    Science.gov (United States)

    Maget, Judith; Kraus, Rainer; Tiebout, Marc

    2002-10-01

    A physical model of a novel MOS varactor design is presented. The voltage and frequency dependent results for the varactors small-signal capacitance and resistance agree well with measured values for different device geometries. The model is further tested through simulating a fully integrated voltage controlled oscillator (VCO) for UMTS applications. Measured frequency tuning and phase noise of the VCO are accurately reproduced.

  18. A Robust 43 GHz VCO in Standard CMOS for OC-768 SONET Applications

    NARCIS (Netherlands)

    Wel, van der Arnoud P.; Gierkink, Sander L.J.; Frye, Robert C.; Bocuzzi, Vito; Nauta, Bram; Franca, J.; Koch, R.

    2003-01-01

    In this paper, we present a 43 GHz VCO in 0.13μm CMOS for use in SONET OC-768 optical networks. The design has a large tune range of 4.2%, which is sufficient to hold the design center frequency over anticipated process spread and temperature variation. A tuned output buffer is used to provide 1.3 V

  19. IC design of low power, wide tuning range VCO in 90 nm CMOS technology

    Science.gov (United States)

    Zhu, Li; Zhigong, Wang; Zhiqun, Li; Qin, Li; Faen, Liu

    2014-12-01

    A low power VCO with a wide tuning range and low phase noise has been designed and realized in a standard 90 nm CMOS technology. A newly proposed current-reuse cross-connected pair is utilized as a negative conductance generator to compensate the energy loss of the resonator. The supply current is reduced by half compared to that of the conventional LC-VCO. An improved inversion-mode MOSFET (IMOS) varactor is introduced to extend the capacitance tuning range from 32.8% to 66%. A detailed analysis of the proposed varactor is provided. The VCO achieves a tuning range of 27-32.5 GHz, exhibiting a frequency tuning range (FTR) of 18.4% and a phase noise of -101.38 dBc/Hz at 1 MHz offset from a 30 GHz carrier, and shows an excellent FOM of -185 dBc/Hz. With the voltage supply of 1.5 V, the core circuit of VCO draws only 2.1 mA DC current.

  20. FORMULASI COLD CREAM PROPRANOLOL UNTUK PENGHANTARAN TRANSDERMAL DENGAN BASIS EMULSI YANG MENGANDUNG VCO (VIRGIN COCONUT OIL

    Directory of Open Access Journals (Sweden)

    Muji Lestari

    2013-11-01

    Full Text Available Propanolol is a non-selective beta-blocker that is used widely to overcome cardiovascular disorder. Development of propranolol in transdermal delivery is necessary to avoid the first pass metabolism that reduces the active metabolite up to 15-23% left. This study was objected to determine the effect of VCO (Virgin Coconut Oil concentration as a base and penetration enhancer of propranolol in the cold cream preparation through rat skin membrane in vitro. Variation concentration of VCO (0%, 14%, 28%, and 42% was added to propanolol cold cream. Transdermal in vitro study was performed using vertical type diffusion cell with PBS pH 7,4 as receptor media. The temperature was maintained at 35ºC with a constant stirring rate at 300 rpm. The transport was conducted for 8 hours. Flux, efficiency, and lag time were calculated as responses. The results showed that flux at various concentration of VCO (0%, 14%, 28%, 42% were 12,30; 14,13; 14,52; and 23,06 -1 cm-2 respectively. The transport efficiency were 6,5x10-4; 7,5x10-4; 8,1x10-4; and 1,22x10-3 % cm-2 respectively. The lag time were 1,13; 1,26; 1,11; and 0,92 hours respectively. It can be concluded that the VCO can be used mainly as a base in the preparation of cold cream and can increase percutaneous permeation of propranolol significantly (p <0.05. VCO concentration of 42% has the highest performance.

  1. Experience with voltage control from large offshore windfarms: The Danish case

    DEFF Research Database (Denmark)

    Akhmatov, Vladislav

    2009-01-01

    This paper gives an overview of the state of the art and lists future challenges to reactive power and voltage control in the Danish transmission system in relation to large offshore windfarms. Today, the reliable and stable operation of the Danish transmission system is based on the voltage...... and several smaller ones, has shown that the efficient use of windfarms' reactive power and voltage control for the on-land transmission system might be limited by several factors. Among such limiting factors are the reactive power and current capability limits of the electronic power converters...... and switchable capacitor banks of the offshore wind turbines, which are smaller than those of central power plants measured per unit of the active power rating. Combine this with the use of AC cables, tens of kilometres long, to connect the large offshore windfarms to the on-land transmission system...

  2. Application of Multipoint DC Voltage Control in VSC-MTDC System

    Directory of Open Access Journals (Sweden)

    Yang Xi

    2013-01-01

    Full Text Available The voltage-source-converter- (VSC- based multiterminal VSC-HVDC power transmission system (VSC-MTDC is an ideal approach to connect wind farm with power grid. Analyzing the characteristics of doubly fed induction generators as well as the basic principle and the control strategy of VSC-MTDC, a multiterminal DC voltage control strategy suitable for wind farm connected with VSC-MTDC is proposed. By use of PSCAD/EMTDC, the proposed control strategy is simulated, and simulation results show that using the proposed control strategy the conversion between constant power control mode and constant DC voltage control mode can be automatically implemented; thus the DC voltage stability control and reliable power output of wind farm can be ensured after the fault-caused outage of converter station controlled by constant DC voltage and under other faults. The simulation result shows that the model can fulfill multiterminal power transmission and fast response control.

  3. Perspectives of voltage control for magnetic exchange bias in multiferroic heterostructures

    Science.gov (United States)

    Yang, Q.; Zhou, Z.; Sun, N. X.; Liu, M.

    2017-04-01

    Exchange bias, as an internal magnetic bias induced by a ferromagnetic-antiferromagnetic exchange coupling, is extremely important in many magnetic applications such as memories, sensors and other devices. Voltage control of exchange bias in multiferroics provides an energy-efficient way to achieve a rapidly 180° deterministic switching of magnetization, which has been considered as a key challenge in realizing next generation of fast, compact and ultra-low power magnetoelectric memories and sensors. Additionally, exchange bias can enhance dynamic magnetoelectric coupling strength in an external-field-free manner. In this paper, we provide a perspective on voltage control of exchange bias in different multiferroic heterostructures. Brief mechanization and related experiments are discussed as well as future trend and challenges that can be overcome by electrically tuning of exchange bias in state-of-the-art magnetoelectric devices.

  4. Deployment of low-voltage regulator considering existing voltage control in medium-voltage distribution systems

    Directory of Open Access Journals (Sweden)

    Hiroshi Kikusato

    2016-01-01

    Full Text Available Many photovoltaic (PV systems have been installed in distribution systems. This installation complicates the maintenance of all voltages within the appropriate range in all low-voltage distribution systems (LVDSs because the trends in voltage fluctuation differ in each LVDS. The installation of a low-voltage regulator (LVR that can accordingly control the voltage in each LVDS has been studied as a solution to this problem. Voltage control in a medium-voltage distribution system must be considered to study the deployment of LVRs. In this study, we installed LVRs in the LVDSs in which the existing voltage-control scheme cannot prevent voltage deviation and performed a numerical simulation by using a distribution system model with PV to evaluate the deployment of the LVRs.

  5. Voltage control and protection in electrical power systems from system components to wide-area control

    CERN Document Server

    Corsi, Sandro

    2015-01-01

    Based on the author’s twenty years of experience, this book shows the practicality of modern, conceptually new, wide area voltage control in transmission and distribution smart grids, in detail. Evidence is given of the great advantages of this approach, as well as what can be gained by new control functionalities which modern technologies now available can provide. The distinction between solutions of wide area voltage regulation (V-WAR) and wide area voltage protection (V-WAP) are presented, demonstrating the proper synergy between them when they operate on the same power system as well as the simplicity and effectiveness of the protection solution in this case. The author provides an overview and detailed descriptions of voltage controls, distinguishing between generalities of underdeveloped, on-field operating applications and modern and available automatic control solutions, which are as yet not sufficiently known or perceived for what they are: practical, high-performance and reliable solutions. At th...

  6. Increasing the Néel temperature of magnetoelectric chromia for voltage-controlled spintronics

    Science.gov (United States)

    Street, M.; Echtenkamp, W.; Komesu, Takashi; Cao, Shi; Dowben, P. A.; Binek, Ch.

    2014-06-01

    Boron doped chromia (Cr2O3) thin films with substitutional doping levels between zero and 3% are grown using pulsed laser deposition in borane background gases. Magnetometry reveals a tunable increase in the Néel temperature of the (0001) textured Cr2BxO3-x thin films at a rate of about 10% with 1% oxygen site substitution preserving a net boundary magnetization. Spin resolved inverse photoemission measured after magnetoelectric annealing in subsequently reversed electric fields evidences voltage-controlled reversal of boundary magnetization and thus magnetoelectricity of Cr2BxO3-x. Conservation of magnetoelectricity far above room temperature makes ultra-low power voltage-controlled spintronic devices feasible.

  7. PSO-Based Voltage Control Strategy for Loadability Enhancement in Smart Power Grids

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-12-01

    Full Text Available This paper proposes a new voltage control methodology using the particle swarm optimization (PSO technique for smart grid loadability enhancement. The goal of this paper is to achieve reliable and efficient voltage profile/stability regulation in power grids. This methodology is based on the decouple power flow equations and the worst-case design technique. Specifically, the secondary voltage control (SVC problem is formulated as an L-infinity norm minimization problem which considers overall load voltage deviations in electrical power systems as an objective model, and the PSO technique is employed to determine a robust control action which aims to improve voltage profile and to enlarge transmission grid loadability by optimal coordinated control of VAR sources. The methodology was successfully tested on several IEEE benchmark systems.

  8. A Synchrophasor Based Optimal Voltage Control Scheme with Successive Voltage Stability Margin Improvement

    Directory of Open Access Journals (Sweden)

    Heng-Yi Su

    2016-01-01

    Full Text Available This paper proposes an optimal control scheme based on a synchronized phasor (synchrophasor for power system secondary voltage control. The framework covers voltage stability monitoring and control. Specifically, a voltage stability margin estimation algorithm is developed and built in the newly designed adaptive secondary voltage control (ASVC method to achieve more reliable and efficient voltage regulation in power systems. This new approach is applied to improve voltage profile across the entire power grid by an optimized plan for VAR (reactive power sources allocation; therefore, voltage stability margin of a power system can be increased to reduce the risk of voltage collapse. An extensive simulation study on the IEEE 30-bus test system is carried out to demonstrate the feasibility and effectiveness of the proposed scheme.

  9. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2014-01-01

    The inherent double line ripple power in singlephase systems is adverse to the converter performance, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active converter topology based...... on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...

  10. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2015-01-01

    converter topology based on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling......The inherent double line ripple power in single-phase systems is adverse to the performance of power electronics converters, e.g. limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active...... of the proposed system is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the stationary reference frame for ripple power compensation. Special attention...

  11. Secondary Frequency and Voltage Control of Islanded Microgrids via Distributed Averaging

    DEFF Research Database (Denmark)

    W. Simpson-Porco, John; Shafiee, Qobad; Dorfler, Florian

    2015-01-01

    actions. The frequency controller rapidly regulates the microgrid frequency to its nominal value while maintaining active power sharing among the distributed generators. Tuning of the voltage controller provides a simple and intuitive trade-off between the conflicting goals of voltage regulation......In this work we present new distributed controllers for secondary frequency and voltage control in islanded microgrids. Inspired by techniques from cooperative control, the proposed controllers use localized information and nearest neighbour communication to collectively perform secondary control...... and reactive power sharing. Our designs require no knowledge of the microgrid topology, impedances or loads. The distributed architecture allows for flexibility and redundancy, and eliminates the need for a central microgrid controller. We provide a voltage stability analysis and present extensive experimental...

  12. Performance Analysis of Phase Controlled Unidirectional and Bidirectional AC Voltage Controllers

    Directory of Open Access Journals (Sweden)

    Abdul Sattar Larik

    2011-01-01

    Full Text Available AC voltage controllers are used to vary the output ac voltage from a fixed ac input source. They are also commonly called ac voltage regulators or ac choppers. The output voltage is either controlled by PAC (Phase Angle Control method or on-off control method. Due to various advantages of ac voltage controllers, such as high efficiency, simplicity, low cost and ability to control large amount of power they efficiently control the speed of ac motors, light dimming and industrial heating, etc. These converters are variable structure systems and generate harmonics during the operation which will affect the power quality when connected to system network. During the last couple of years, a number of new semiconductor devices and various power electronic converters has been introduced. Accordingly the subject of harmonics and its problems are of great concern to power industry and customers. In this research work, initially the simulation models of single phase unidirectional and bidirectional ac voltage controllers were developed by using MATLAB software. The harmonics of these models are investigated by simulation. In the end, the harmonics were also analyzed experimentally. The simulated as well as experimental results are presented.

  13. The Optimum Design Methodology of Low-Phase-Noise LC-VCO Using Multiple-Divide Technique

    Science.gov (United States)

    Hara, Shoichi; Murakami, Rui; Okada, Kenichi; Matsuzawa, Akira

    The multiple-divide technique, using the multi-ratio frequency divider, has a possibility to improve FoM of VCO. This paper proposes a design optimization of LC-VCO using the multiple-divide technique. In the simulated results using 90-nm CMOS model parameters, the optimum frequency range, achieving better than -187.0dBc/Hz of FoM, can be extended from 6.5-12.5GHz to 1.5-12.5GHz. The proposed multiple-divide technique can provide a lower phase-noise, lower power consumption, smaller layout area of LC-VCO.

  14. A bulk-controlled ring-VCO with 1/f-noise reduction for frequency ΔΣ modulator

    DEFF Research Database (Denmark)

    Tuan Vu, CAO; Wisland, Dag T.; Lande, Tor Sverre

    The paper introduces a bulk-controlled ring-VCO with a tail transistor utilizing flicker-noise (1/f-noise) reduction techniques for a frequency-based DeltaSigma modulator (FDSM). This VCO converts an analog input voltage to phase information under various bias conditions ranging from sub......-threshold to saturation. By using the 1/f-noise reduction circuit which is based on the switched bias technique, the simulations indicate that less noise is transferred to the output when the 1/f-noise reduction circuit is used. The phase noise of the proposed VCO is improved by 7.6% while maintaining tuning...

  15. SIFAT FUNGSIONAL ISOLAT PROTEIN ‘BLONDO’ (COCONUT PRESSCAKE DARI PRODUK SAMPING PEMISAHAN VCO (VIRGIN COCONUT OIL DENGAN BERBAGAI METODE

    Directory of Open Access Journals (Sweden)

    Siti Permatasari

    2015-11-01

    OHC tidak menunjukkan perbedaan yang signifikan antar metode (p≤ 0,05. Hasil penelitian ini menyimpulkan bahwa metode fisik menghasilkan sifat fungsional terbaik. Kata kunci: Sifat fungsional, isolat protein, blondo, VCO

  16. Design and Tuning of Wind Power Plant Voltage Controller with Embedded Application of Wind Turbines and STATCOMs

    DEFF Research Database (Denmark)

    Petersen, Lennart; Kryezi, Fitim; Iov, Florin

    2017-01-01

    . A complete phasor model of the entire wind power plant is constructed, being appropriate for voltage control assessment. An exemplary wind power plant located in the United Kingdom and the corresponding grid code requirements are used as a base case. The final design and tuning process of the voltage...... controller results in a guidance, proposed for this particular control architecture. It provides qualitative outcomes regarding the parametrisation of each individual control loop and how to adjust the voltage controller depending on different grid stiffnesses of the wind power plant connection...

  17. Steady State Condition in the Measurement of VO2and VCO2by Indirect Calorimetry.

    Science.gov (United States)

    Cadena, M; Sacristan, E; Infante, O; Escalante, B; Rodriguez, F

    2005-01-01

    Resting Metabolic Rate (RMR) is computed using VO2and VCO2short time 15-minute window measurement with Indirect Calorimetry (IC) instruments designed with mixing chamber. Steady state condition using a 10% variation coefficient criteria is the main objective to achieve metabolic long time prediction reliability. This study address how susceptible is the steady state VO2, VCO2measurement condition to the clino-orthostatic physiological maneuver. 30 young healthy subjects were analyzed. Only 18 passed the 10% variation coefficient inclusive criteria. They were exposed to 10 minutes clino-stage and 10 minutes orthostage. The hypothesis tests show not statistical significance (p< 0.1) in the average and variance analysis. It is concluded that the steady state is not influenced by the patient position IC test, probably because IC mixing chamber instruments are insensitive to detect a mayor physiological dynamics changes that can modify the steady state definition.

  18. A Wide Tuning-Range CMOS VCO with a Tunable Active Inductor

    Directory of Open Access Journals (Sweden)

    Hsuan-Ling Kao

    2015-01-01

    Full Text Available This study describes a wide tuning-range VCO using tunable active inductor (TAI topology and cross-coupled pair configuration for radio frequency operation. The TAI used two feedback loops to form a cascode circuit to obtain more degrees of freedom for inductance value. The TAI-VCO was fabricated using a 0.18 μm CMOS technology. The coarse frequency tuning is achieved by TAIs while the fine tuning is controlled by varactors. The fabricated circuit provides an output frequency range from 0.6 to 7.2 GHz (169%. The measured phase noise is from −110.38 to −86.01 dBc/Hz at a 1 MHz offset and output power is from −11.11 to −3.89 dBm within the entire frequency range under a 1.8 V power supply.

  19. Design of Transmission Gate VCO and Dynamic PFD for Low Power CMOS PLL

    Science.gov (United States)

    Yuan, S. C.

    2008-11-01

    To realize the high speed and low power CMOS PLL(Phase Locked Loop), the new circuits of VCO and PFD is designed in transistor level. In the VCO, the high speed and low power is realized using transmission-gate(TG) with an adaptive delay cell and low supply sensitivity. This delay cell has a built-in compensation circuit that senses and corrects the delay variation caused by supply fluctuation. And in the PFD, low power and small chip area is realized with the dynamic inverter. A fully CMOS PLL using these components has been designed based 0.6μm CMOS technology and its SPICE model. SPICE simulation results show that at 2.5V supply voltage, the designed PLL can operate over 1000MHz and dissipate power less than 50mW.

  20. A Voltage Controller in Photo-Voltaic System with Battery Storage for Stand-Alone Applications

    Directory of Open Access Journals (Sweden)

    Ganesh Dharmireddy

    2012-01-01

    Full Text Available This paper proposes the new voltage controller in photo-voltaic system for Stand-Alone Applications with battery energy storage. The output of the PV array is unregulated DC supply due to change in weather conditions. The maximum power is tracked with respect to temperature and irradiance levels by using DC-DC converter. The perturbation and observes algorithm is applied for maximum power point tracking (MPPT purpose. This algorithm is selected due to its ability to withstand against any parameter variation and having high efficiency. The solar cell array powers the steady state energy and the battery compensates the dynamic energy in the system. The aim of the control strategy is to control the SEPIC converter and bi-direction DC-DC converter to operate in suitable modes according to the condition of solar cell and battery, so as to coordinate the two sources of solar cell and battery supplying power and ensure the system operates with high efficiency and behaviors with good dynamic performance. The output of DC-DC converter is converted to AC voltage by using inverter.  The AC output voltage and frequency are regulated. A closed loop voltage control for inverter is done by using unipolar sine wave pulse width modulation (SPWM. The regulated AC voltage is fed to AC standalone loads or grid integration. The overall system is designed, developed and validated by using MATLAB-SIMULINK. The simulation results demonstrate the effective working of MPPT algorithm, control strategy and voltage controller with SPWM technique for inverter in AC standalone load applications.

  1. A dual voltage control strategy for single-phase PWM converters with power decoupling function

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2014-01-01

    on a symmetrical half bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system...... is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the harmonic reference frame for ripple power compensation. Special attention is given to the bandwidth...

  2. Voltage-controlled spin selection in a magnetic resonant tunneling diode.

    Science.gov (United States)

    Slobodskyy, A; Gould, C; Slobodskyy, T; Becker, C R; Schmidt, G; Molenkamp, L W

    2003-06-20

    We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and could be the first step towards a voltage controlled spin filter.

  3. Stability and bifurcation in a voltage controlled negative-output KY Boost converter

    Science.gov (United States)

    Wang, Fa-Qiang; Ma, Xi-Kui

    2011-03-01

    The stability and bifurcation in a voltage controlled negative-output KY Boost converter is studied in this Letter. A glimpse at the stability and bifurcation from the power electronics simulator (PSIM) software are given. And then, its mathematical model and corresponding discrete model are derived. The stability and bifurcation of the converter are determined with the help of the loci of eigenvalues of the Jacobian matrix. It is found that the Hopf bifurcation is easy to come in this converter when the value of its energy-transferring capacitor increases. Finally, the analytical results are confirmed by the circuit experiment.

  4. Internal voltage control of hydrogen-oxygen fuel cells: Feasibility study

    Science.gov (United States)

    Prokopius, P. R.

    1975-01-01

    An experimental study was conducted to assess the feasibility of internal voltage regulation of fuel cell systems. Two methods were tested. In one, reactant partial pressure was used as the voltage control parameter and in the other reactant total pressure was used for control. Both techniques were breadboarded and tested on a single alkaline-electrolyte fuel cell. Both methods were found to be possible forms of regulation, however, of the two the total pressure technique would be more efficient, simpler to apply and would provide better transient characteristics.

  5. Design to conditioning circuits of dynamic compensation of reactive power in the intelligence voltage controller

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.

  6. Voltage-controlled accommodating IOL system using an ion polymer metal composite actuator.

    Science.gov (United States)

    Horiuchi, Tetsuya; Mihashi, Toshifumi; Fujikado, Takashi; Oshika, Tetsuro; Asaka, Kinji

    2016-10-03

    Surgeons treat cataracts by replacing the clouded lens with an intraocular lens (IOL), but patients are required to wear reading glasses for tasks requiring near vision. We suggest a new voltage-controlled accommodating IOL made of an ionic polymer metal composite (IPMC) actuator to change focus. An in vitro experiment was conducted where an actuator was placed inside the eye and moved with applied voltage. The lens attached to the actuator was deformed by its movement to change the patient's focus. The results showed that this system can accommodate a change of approximately 0.8 diopters under an applied voltage of ± 1.3 V.

  7. Voltage-controlled sub-terahertz radiation transmission through GaN quantum well structure

    Science.gov (United States)

    Laurent, T.; Sharma, R.; Torres, J.; Nouvel, P.; Blin, S.; Varani, L.; Cordier, Y.; Chmielowska, M.; Chenot, S.; Faurie, J.-P.; Beaumont, B.; Shiktorov, P.; Starikov, E.; Gruzinskis, V.; Korotyeyev, V. V.; Kochelap, V. A.

    2011-08-01

    We report on measurements of radiation transmission in the 0.220-0.325 THz frequency range through GaN quantum wells grown on sapphire substrates at nitrogen and room temperatures. Significant enhancement of the transmitted beam intensity with applied voltage is found at nitrogen temperature. This effect is explained by changes in the mobility of two-dimensional electrons under electric bias. We have clarified which physical mechanism modifies the electron mobility and we suggest that the effect of voltage-controlled sub-terahertz transmission can be used for the development of electro-optic modulators operating in the sub-THz frequency range.

  8. Wind Power Plant Voltage Control Optimization with Embedded Application of Wind Turbines and Statcom

    DEFF Research Database (Denmark)

    Wu, Qiuwei; Solanas, Jose Ignacio Busca; Zhao, Haoran

    2017-01-01

    Increasing wind power penetration and the size of wind power plants (WPPs) brings challenges to the operation and control of power systems. Most of WPPs are located far from load centers and the short circuit ratio at the point of common coupling (PCC) is low. The fluctuations of wind power...... will cause voltage variations. An optimal voltage control scheme for WPPs with STATCOMs is presented in the paper. It ensures that the voltages within the WPPs and at the high voltage side of the WPPs are within the limits and maximizes the dynamic Var reserve of the WPPs. Case studies were conducted...

  9. Multi-Period Optimization for Voltage Control System in Transmission Grids

    DEFF Research Database (Denmark)

    Qin, Nan; Chen, Si; Liu, Chengxi

    2015-01-01

    Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes....... In the lower level, the optimization is focused on the correction of the voltage violations every single minute based on data from the measurements and state estimation. The presented case study shows that the multi-period optimization in the upper level of AVC system can reduce adjustment times...

  10. Formulation and stability of whitening VCO-in-water nano-cream.

    Science.gov (United States)

    Al-Edresi, Sarmad; Baie, Saringat

    2009-05-21

    Virgin coconut oil (VCO)-in-water, nano-emulsion in the form of cream stabilized by Emulium Kappa as an emulsifier, was prepared by using the Emulsion Inversion Point method. A nano-emulsion with droplet size VCO has recently become a more popular new material in the cosmetic industries. Emulium Kappa is an ionic emulsifier that contains sodium stearoyl lactylate, the active whitening ingredient was Kojic Dipalmitate. Ostwald ripening is the main destabilizing factor for the nano-emulsion. This decline can be reduced by adding non-soluble oil, namely squalene, to the virgin coconut oil. We tested VCO:squalene in the ratios of 10:0, 9.8:0.2, 9.6:0.4, 9.4:0.6, 9.2:0.8, 9:1 and 8:2 and discovered that squalene's higher molecular weight (above critical molecular weight) resulted in low polarity and insolubility in the continuous phase. The continuous partitioning between the droplets results in the decline of Ostwald ripening. Furthermore, flocculation may occur due to the instability of nano-emulsion, especially for the preparations with little or no squalene at all. The stability of the nano-emulsion was evaluated by the electrophoretic properties of the emulsion droplets. The zeta potential values for the emulsion increased as the percentage of squalene oil increased.

  11. VCO Production from Fresh Old Coconut Bunch by Circulating and Pumping Method

    Directory of Open Access Journals (Sweden)

    Muhamad Maulana Azimatun Nur

    2012-02-01

    Full Text Available VCO (Virgin Coconut Oil is one of coco-diesel source, made without high heating and chemicals. Commercial processes production, such fermentation and centrifugation usually need more time and expensive in cost and investment. Circulating by pumping through a nozzle is a new process method invented to produce VCO. The process followed by coalescence method, breaking emulsion by hitting particles through pipe and nozzle. The problem of this method was that the product gave lower yield than another method and not yet qualified. This research was purposed to discover correlation between pressure and time of circulation variables against yield and content (FFA, Peroxide, water content represented by SNI (national Indonesian standard. Producing VCO initiated by producing coconut milk from fresh old coconut, then each 1 litre milk were pumped through the pipe and nozzle with variation of circulations pressures and time. The results were decanted for 10 hours so the oil and water would be separated. The oil at upper layer was taken as final product. Then the last step was analysed the oils and oil cake (blondo. The results showed that pressure and time of circulating variables gave impact to the yield. On optimum variables, 2 atm pressure and 15 minutes of circulating gave better results with 97% yield. This operating variables also affecting oil quality. The minimum water content is 0.1%, free fatty acid is 0.18% and peroxide value is 2 mg/kg eq. The results showed that all of parameters meet the SNI standard.

  12. VCO Production from Fresh Old Coconut Bunch by Circulating and Pumping Method

    Directory of Open Access Journals (Sweden)

    Muhamad Maulana Azimatun Nur

    2012-04-01

    Full Text Available VCO (Virgin Coconut Oil is one of coco-diesel source, made without high heating and chemicals. Commercial processes production, such fermentation and centrifugation usually need more time and expensive in cost and investment. Circulating by pumping through a nozzle is a new process method invented to produce VCO. The process followed by coalescence method, breaking emulsion by hitting particles through pipe and nozzle. The problem of this method was that the product gave lower yield than another method and not yet qualified. This research was purposed to discover correlation between pressure and time of circulation variables against yield and content (FFA, Peroxide, water content represented by SNI (national Indonesian standard. Producing VCO initiated by producing coconut milk from fresh old coconut, then each 1 litre milk were pumped through the pipe and nozzle with variation of circulations pressures and time. The results were decanted for 10 hours so the oil and water would be separated. The oil at upper layer was taken as final product. Then the last step was analysed the oils and oil cake (blondo. The results showed that pressure and time of circulating variables gave impact to the yield. On optimum variables, 2 atm pressure and 15 minutes of circulating gave better results with 97% yield. This operating variables also affecting oil quality. The minimum water content is 0.1%, free fatty acid is 0.18% and peroxide value is 2 mg/kg eq. The results showed that all of parameters meet the SNI standard.

  13. Processing Methode Effect to Virgin Coconut Oil (VCO Quality After Storaging

    Directory of Open Access Journals (Sweden)

    Mimi Harni

    2014-01-01

    Full Text Available Virgin Coconut Oil (VCO is extracted from coconut milk cream by breaking up the coconut milk emulsion in some ways like heat using, centrifugation, fermentation, inducement and acid using.  The difference of oil extraction ways will influence produced oil quality and oil storage capacity then.  Low quality oil will be boosting earlier damage process while storage time.  Therefore, it had been done a research in Chemical Laboratory of Agricultural Polytechnic state of Payakumbuh. The design used in this research was Complete Random Design (CRD by 5 (five actions and 3 (Three repetitions. For the advance test would be done by Duncan’s New Multiple Rang Test (DNMRT at about 5 % real level.  The Observations that had been done in this research were free fat acid, peroxide number and saponification number in storaged dark glass bottle VCO. The result of research showed the VCO oil that had the best quality after storaging  was the oil made by centrifugation process with 0,68% free fat acid value, 5,49 % meq/Kg oil peroxide number and 205,05 mg KOH/g oil saponification number.

  14. Voltage control in Z-source inverter using low cost microcontroller for undergraduate approach

    Science.gov (United States)

    Zulkifli, Shamsul Aizam; Sewang, Mohd Rizal; Salimin, Suriana; Shah, Noor Mazliza Badrul

    2017-09-01

    This paper is focussing on controlling the output voltage of Z-Source Inverter (ZSI) using a low cost microcontroller with MATLAB-Simulink that has been used for interfacing the voltage control at the output of ZSI. The key advantage of this system is the ability of a low cost microcontroller to process the voltage control blocks based on the mathematical equations created in MATLAB-Simulink. The Proportional Integral (PI) control equations are been applied and then, been downloaded to the microcontroller for observing the changes on the voltage output regarding to the changes on the reference on the PI. The system has been simulated in MATLAB and been verified with the hardware setup. As the results, the Raspberry Pi and Arduino that have been used in this work are able to respond well when there is a change of ZSI output. It proofed that, by applying/introducing this method to student in undergraduate level, it will help the student to understand more on the process of the power converter combine with a control feedback function that can be applied at low cost microcontroller.

  15. Voltage Controlled Exchange Bias in a Cr2O3 based heterostructure

    Science.gov (United States)

    Echtenkamp, Will; Street, Mike; Binek, Christian

    2015-03-01

    Controlling magnetism by electrical means is a key challenge in the field of spintronics, and electric control of exchange bias is one of the most promising routes to address this challenge. Isothermal electric control of exchange bias has been achieved near room temperature using bulk, single crystal, magnetoelectric Cr2O3, which has a voltage controlled net magnetization at the (0001) surface. Voltage control of magnetism in a Cr2O3 thin film system has presented significant challenges. In this study we explore the electric control of exchange bias in an all-thin-film system of decreasing chromia film thickness with significant implications for scalability of ultra-low power memory and logical devices. Cross-sectional HRTEM indicates that grain boundaries in the metallic bottom electrode propagate into the Cr2O3 thin film with detrimental effects on leakage currents. We address this issue via a three-step growth method for the deposition of epitaxial Pd on sapphire. The resulting microstructure of the films is analyzed by reflection high-energy electron diffraction, tunneling electron microscopy and x-ray diffraction. This project was supported by SRC through CNFD, an SRC-NRI Center, by C-SPIN, part of STARnet, and by the NSF through MRSEC DMR-0820521.

  16. Eliminating leakage current in voltage-controlled exchange-bias devices

    Science.gov (United States)

    Mahmood, Ather; Echtenkamp, Will; Street, Michael; Binek, Christian; Magnetic Heterostructures Team

    Manipulation of magnetism by electric field has drawn much attention due to the technological importance for low-power devices, and for understanding fundamental magnetoelectric phenomena. A manifestation of electrically controlled magnetism is voltage control of exchange bias (EB). Robust isothermal voltage control of EB was demonstrated near room temperature using a heterostructure of Co/Pd thin film and an exchange coupled single crystal of the antiferromagnetic Cr2O3 (Chromia). A major obstacle for EB in lithographically patterned Chromia based thin-film devices is to minimize the leakage currents at high electric fields (>10 kV/mm). By combining electrical measurements on patterned devices and conductive Atomic Force Microscopy of Chromia thin-films, we investigate the defects which form conducting paths impeding the application of sufficient voltage for demonstrating the isothermal EB switching in thin film heterostructures. Technological challenges in the device fabrication will be discussed. This project was supported by SRC through CNFD, an SRC-NRI Center, by C-SPIN, part of STARnet, and by the NSF through MRSEC Abstract DMR-0820521.

  17. Voltage Control of Exchange Bias in a Chromium Oxide Based Thin Film Heterostructure

    Science.gov (United States)

    Echtenkamp, Will; Street, Mike; Mahmood, Ather; Binek, Christian

    Controlling magnetism by electrical means is a key challenge in the field of spintronics, and electric control of exchange bias is one of the most promising routes to address this challenge. Isothermal electric control of exchange bias has been achieved near room temperature using bulk, single crystal, magnetoelectric Cr2O3. In this study the electrically-controlled exchange bias is investigated in an all thin film Cr2O3/PdCo exchange bias heterosystem where an MBE grown ferromagnetic and perpendicular anisotropic Pd/Co multilayer has been deposited on a PLD grown (0001) Cr2O3 thin film. Prototype devices are fabricated using lithography techniques. Using a process of magnetoelectric annealing, voltage control of exchange bias in Cr2O3 heterostructures is demonstrated with significant implications for scalability of ultra-low power memory and logical devices. In addition, the dependence of the exchange bias on the applied electric and magnetic fields are independently studied at 300K and isothermal voltage-controlled switching is investigated. This project was supported by SRC through CNFD, an SRC-NRI Center, by C-SPIN, part of STARnet, and by the NSF through MRSEC DMR-0820521.

  18. P Voltage Control of DFIG with Two-Mass-Shaft Turbine Model Under Utility Voltage Disturbance

    Directory of Open Access Journals (Sweden)

    Hengameh Kojooyan Jafari

    2016-06-01

    Full Text Available Doubly fed induction generators as a variable speed induction generators are applied instead of other electric machines in wind power plants to be connected to the grid with flexible controllers. Nowadays one of the most important subjects in wind farms is control of output power delivered to the grid under utility disturbance. In this paper, a doubly-fed induction generator with external rotor resistance and power converters model as an external voltage source having an adjustable phase and amplitude with an ordinary turbine connected to one mass shaft model and also two mass shaft model, is used and controlled by a P voltage controller to control the output active power for typical high and low wind speeds under two conditions of utility disturbance; while time of disturbance is not too long to change the domain of external rotor voltage source and also while time is long and the domain of external rotor voltage decreases.Simulation results show that P voltage controller can control output active power under 27% stator voltage drop down for typical low wind speed and 11% stator voltage drop down for typical high wind speed in long time disturbance while 80% of rotor external voltage domain drops down under short time utility disturbance.

  19. Optoelectronic Oscillators for Communication Systems

    Science.gov (United States)

    Romeira, Bruno; Figueiredo, José

    We introduce and report recent developments on a novel five port optoelectronic voltage controlled oscillator consisting of a resonant tunneling diode (RTD) optical-waveguide integrated with a laser diode. The RTD-based optoelectronic oscillator (OEO) has both optical and electrical input and output ports, with the fifth port allowing voltage control. The RTD-OEO locks to reference radio-frequency (RF) sources by either optical or electrical injection locking techniques allowing remote synchronization, eliminating the need of impedance matching between traditional RF oscillators. RTD-OEO functions include generation, amplification and distribution of RF carriers, clock recovery, carrier recovery, modulation and demodulation and frequency synthesis. Self-injection locking operation modes, where small portions of the output electrical/optical signals are fed back into the electrical/optical input ports, are also proposed. The self-phase locked loop configuration can give rise to low-noise high-stable oscillations, not limited by the RF source performance and with no need of external optoelectronic conversion.

  20. A Precise Robust Fuzzy Control of Robots Using Voltage Control Strategy

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mehdi Fateh; Sara Fateh

    2013-01-01

    Fuzzy control of robot manipulators with a decentralized structure is facing a serious challenge.The state-space model of a robotic system including the robot manipulator and motors is in non-companion form,multivariable,highly nonlinear,and heavily coupled with a variable input gain matrix.Considering the problem,causes and solutions,we use voltage control strategy and convergence analysis to design a novel precise robust fuzzy control (PRFC) approach for electrically driven robot manipulators.The proposed fuzzy controller is Mamdani type and has a decentralized structure with guaranteed stability.In order to obtain a precise response,we regulate a fuzzy rule which governs the origin of the tracking space.The proposed design is verified by stability analysis.Simulations illustrate the superiority of the PRFC over a proprotional derivative like (PD-like) fuzzy controller applied on a selective compliant assembly robot arm (SCARA) driven by permanent magnet DC motors.

  1. Effect of strain on voltage-controlled magnetism in BiFeO₃-based heterostructures.

    Science.gov (United States)

    Wang, J J; Hu, J M; Yang, T N; Feng, M; Zhang, J X; Chen, L Q; Nan, C W

    2014-04-01

    Voltage-modulated magnetism in magnetic/BiFeO3 heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO3 and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO3 film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO3 that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO3-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO3-based heterostructures.

  2. Effects of voltage control in utility interactive dispersed storage and generation systems

    Energy Technology Data Exchange (ETDEWEB)

    Kirkham, H.; Das, R.

    1983-03-15

    When a small generator is connected to the distribution system, the voltage at the point of interconnection is determined largely by the system and not the generator. This report examines the effect on the generator, on the load voltage and on the distribution system of a number of different voltage control strategies in the generator. Synchronous generators with three kinds of exciter control are considered, as well as induction generators and dc/ac inverters, with and without capacitor compensation. The effect of varying input power during operation (which may be experienced by generators based on renewable resources) is explored, as well as the effect of connecting and disconnecting the generator at ten percent of its rated power.

  3. Voltage controller design for air conditioning; Diseno de controlador de voltaje para aire acondicionado

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Andrade, R; Lopez Villalobos, J.J; Valderrama Chairez, J; Ramirez, R.L. [Instituto Tecnologico de Nuevo Leon, Guadalupe, Nuevo Leon (Mexico)]. E-mails: roxana_garciaandrade@yahoo.com; xe2n@yahoo.com.mx; jose.valderrama@ieee.org

    2013-03-15

    This paper discusses the design of a voltage controller for an air conditioning system in order to generate additional power in activation or startup of the system, for which as a first stage is presented the modeling power generation of electric current through alternative means, such as solar energy. The results of this study will be the basis for development of the physical prototype of this system controller. [Spanish] El presente trabajo trata sobre el diseno de un controlador de voltaje para un sistema de aire acondicionado con el fin de generar energia adicional en la activacion o arranque de dicho sistema, para lo cual como primer fase se presenta el modelado de la generacion de corriente electrica mediante medios alternos, como lo es la energia solar. Los resultados de este trabajo seran la base para desarrollo del prototipo fisico de este sistema controlador.

  4. A Novel Neutral Point Voltage Control Strategy for Three-Level NPC APF Based on SVPWM

    Directory of Open Access Journals (Sweden)

    Yao Xiaolong

    2015-01-01

    Full Text Available The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC Active Power Filter (APF; this paper analyzes the causes of unbalanced neutral point voltage and studies the reason of the unbalance of the neutral point voltage. A novel neutral point voltage control strategy using Space Vector Pulse Width Modulation (SVPWM is proposed. The proposed strategy is based on the traditional SVPWM, by controlling the effect time of small vector, which can change the state of the midpoint voltage fluctuation, and the neutral point voltage can be maintained balance. The influence of the vector on neutral point balance is investigated in depth. Simulation results show the neutral point voltage balancing control strategy based on SPWM is effective.

  5. Near-room-temperature refrigeration through voltage-controlled entropy change in multiferroics

    Science.gov (United States)

    Binek, Ch.; Burobina, V.

    2013-01-01

    Composite materials with large magnetoelectric effect are proposed for application in advanced near-room-temperature refrigeration. The key innovation rests on utilizing the magnetocaloric effect in zero applied magnetic fields. This approach promises sizable isothermal entropy change and virtually temperature-independent refrigerant capacity through pure voltage-control. It is in sharp contrast with the conventional method of exploiting the magnetocaloric effect through applied magnetic fields. We outline the thermodynamics and estimate an isothermal entropy change specifically for the La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3)O3-PbTiO3(001) two-phase composite material. Finally, we propose structural variations of two-phase composites, which help in overcoming the challenging task of producing nanostructured material in macroscopic quantities.

  6. Voltage Control of Distribution Grids with Multi-Microgrids Using Reactive Power Management

    Directory of Open Access Journals (Sweden)

    WLODARCZYK, P.

    2015-02-01

    Full Text Available Low-voltage Microgrids can be valuable sources of ancillary services for the Distribution System Operators (DSOs. The aim of this paper was to study if and how multi-microgrids can contribute to Voltage Control (VC in medium-voltage distribution grids by means of reactive power generation and/or absorption. The hierarchical control strategy was proposed with the main focus on the tertiary control which was defined as optimal power flow problem. The interior-point algorithm was applied to optimise experimental benchmark grid with the presence of Distributed Energy Resources (DERs. Moreover, two primary objectives were formulated: active power losses and amount of reactive power used to reach the voltage profile. As a result the active power losses were minimised to the high extent achieving the savings around 22% during entire day.

  7. Highly tunable local gate controlled complementary graphene device performing as inverter and voltage controlled resistor.

    Science.gov (United States)

    Kim, Wonjae; Riikonen, Juha; Li, Changfeng; Chen, Ya; Lipsanen, Harri

    2013-10-04

    Using single-layer CVD graphene, a complementary field effect transistor (FET) device is fabricated on the top of separated back-gates. The local back-gate control of the transistors, which operate with low bias at room temperature, enables highly tunable device characteristics due to separate control over electrostatic doping of the channels. Local back-gating allows control of the doping level independently of the supply voltage, which enables device operation with very low VDD. Controllable characteristics also allow the compensation of variation in the unintentional doping typically observed in CVD graphene. Moreover, both p-n and n-p configurations of FETs can be achieved by electrostatic doping using the local back-gate. Therefore, the device operation can also be switched from inverter to voltage controlled resistor, opening new possibilities in using graphene in logic circuitry.

  8. Coordinated voltage control in smart grids subject to a fair contribution of reactive power

    Energy Technology Data Exchange (ETDEWEB)

    Kolenc, Marko; Papic, Igor; Blazic, Bostjan [Ljubljana Univ. (Slovenia). Faculty of Electrical Engineering

    2012-07-01

    The paper analyses the influence of distributed generation (DG) on voltage profile and distribution losses. Connection of DG units to a distribution network results in a local voltage increase and usually reduction of losses. The focus of the paper is on development of a control strategy to keep the voltage within permissible limits, minimize losses and assure fairness regarding reactive power contributions. As the new technologies nowadays allow bidirectional data flow in almost real time, more active participation of generators in voltage control is possible. Different solutions were evaluated by means of simulations. The simulated network was an actual Slovenian medium-voltage distribution network which covers a large area with diverse feeders and thus gives relatively general results. The network was modified by increasing the number of DG (especially photovoltaic) as the growth of DG is very fast in Slovenia. (orig.)

  9. A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller

    Directory of Open Access Journals (Sweden)

    Ahmet ALTINTAŞ

    2009-04-01

    Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.

  10. Switchable voltage control of the magnetic coercive field via magnetoelectric effect

    Science.gov (United States)

    Wang, Jing; Ma, Jing; Li, Zheng; Shen, Yang; Lin, Yuanhua; Nan, C. W.

    2011-08-01

    Switchable voltage modulation of the magnetic properties is reported in different multiferroic bilayers with magnetic films grown on pre-poled ferroelectric substrates, based on the magneto-optical Kerr effect observations. The dynamic voltage control of the magnetic coercive field (Hc) is dependent not only on the materials properties of each ferroic layer, but also on the bias voltage history. The Hc versus electric field behaviors essentially track the dependence of the piezostrains of the substrates on the bias voltage. The observations demonstrate that Hc in such multiferroic bilayers can be controlled by voltage via strain-mediated magnetoelectric coupling and that the Hc change is not an artifact due to a heating effect.

  11. Voltage control of the magnetic coercive field: Multiferroic coupling or artifact?

    Science.gov (United States)

    Vopsaroiu, M.; Cain, M. G.; Woolliams, P. D.; Weaver, P. M.; Stewart, M.; Wright, C. D.; Tran, Y.

    2011-03-01

    The ability to dynamically tune the coercive field of magnetic thin films is a powerful tool for applications, including in magnetic recording disk technologies. Recently, a number of papers have reported the electrical voltage control of the coercive field of various magnetic thin films in multiferroic composites. Theoretically, this is possible in magneto-electric (ME) multiferroics due to the piezoferroelectric component that can be electrically activated to dynamically modify the properties of the magnetic component of the composite via a direct or strain mediated ME coupling. In this paper we fabricated and examined such structures and we determined that the magnetic coercive field reduction is most likely due to a heating effect. We concluded that this effect is probably an artifact that cannot be attributed to a multiferroic coupling.

  12. Implementation of Inverter with Flexible Voltage Control for A DC Line in a System

    Directory of Open Access Journals (Sweden)

    M. Mohanraj

    2014-02-01

    Full Text Available Due to raising demands in electric power it becomes more important to use the available energy sources efficiently and along with them the distributed generation comes into picture which means collection of energy from many small sources say RES. For distribute generation (DG systems a challenging issue is to smartly integrate renewable-energy sources into the grid as it leads to power quality problems under fault conditions. Another approach for meeting the power demand is to implement TEP .This work proposes an method which uses a control algorithm for inverters for providing a flexible voltage control using reference current generation under grid faults. The controlled inverter designed is used for inversion processes at the receiving end in a HVDC line. A system with three sources is considered, their performances if the three lines connecting three sources are AC lines and if one line is replaced with a DC line is studied. Keywords –

  13. Voltage-controlled separation of proteins by electromobility focusing in a dialysis hollow fiber.

    Science.gov (United States)

    Wang, Qinggang; Lin, Shu-Ling; Warnick, Karl F; Tolley, H Dennis; Lee, Milton L

    2003-01-24

    Electromobility focusing (EMF) is a relatively new protein separation technique that utilizes an electric field gradient and a hydrodynamic flow. Proteins are focused in order of electrophoretic mobility at points where their electrophoretic migration velocities balance the hydrodynamic flow velocity. Steady state bands are formed along the separation channel when equilibrium is reached. Further separation and detection can be easily achieved by changing the electric field profile. In this paper. we describe an EMF system with on-line UV absorption detection in which the electric field gradient was formed using a dialysis hollow fiber. Protein focusing and preconcentration were performed with this system. Voltage-controlled separation was demonstrated using bovine serum albumin and myoglobin as model proteins. The limitations of the current method are discussed, and possible solutions are proposed.

  14. Coordinated Voltage Control of a Wind Farm based on Model Predictive Control

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Guo, Qinglai

    2016-01-01

    This paper presents an autonomous wind farm voltage controller based on Model Predictive Control (MPC). The reactive power compensation and voltage regulation devices of the wind farm include Static Var Compensators (SVCs), Static Var Generators (SVGs), Wind Turbine Generators (WTGs) and On......-Load Tap Changing (OLTC) Transformer, and they are coordinated to keep the voltages of all the buses within the feasible range. Moreover, the reactive power distribution is optimized throughout the wind farm in order to maximize the dynamic reactive power reserve. The sensitivity coefficients...... are calculated based on an analytical method to improve the computation efficiency and overcome the convergence problem. Two control modes are designed for both voltage violated and normal operation conditions. A wind farm with 20 wind turbines was used to conduct case studies to verify the proposed coordinated...

  15. Improved PHIP polarization using a precision, low noise, voltage controlled current source

    Science.gov (United States)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  16. Improved PHIP polarization using a precision, low noise, voltage controlled current source.

    Science.gov (United States)

    Agraz, Jose; Grunfeld, Alexander; Cunningham, Karl; Li, Debiao; Wagner, Shawn

    2013-10-01

    Existing para-hydrogen induced polarization (PHIP) instrumentation relies on magnetic fields to hyperpolarize substances. These hyperpolarized substances have enhanced magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for MRI at the molecular level. Required magnetic fields are generated by energizing a solenoid coil with current produced by a voltage controlled voltage source (VCVS), also known as a power supply. A VCVS lacks the current regulation necessary to keep magnetic field fluctuations to a minimum, which results in low PHIP polarization. A voltage controlled current source (VCCS) is an electric circuit that generates a steady flow of electrons proportional to an input voltage. A low noise VCCS provides the solenoid current flow regulation necessary to generate a stable static magnetic field (Bo). We discuss the design and implementation of a low noise, high stability, VCCS for magnetic field generation with minimum variations. We show that a precision, low noise, voltage reference driving a metal oxide semiconductor field effect transistor (MOSFET) based current sink, results in the current flow control necessary for generating a low noise and high stability Bo. In addition, this work: (1) compares current stability for ideal VCVS and VCCS models using transfer functions (TF), (2) develops our VCCS design's TF, (3) measures our VCCS design's thermal & 1/f noise, and (4) measures and compares hydroxyethyl-propionate (HEP) polarization obtained using a VCVS and our VCCS. The hyperpolarization of HEP was done using a PHIP instrument developed in our lab. Using our VCCS design, HEP polarization magnitude data show a statistically significant increase in polarization over using a VCVS. Circuit schematic, bill of materials, board layout, TF derivation, and Matlab simulations code are included as supplemental files.

  17. Improved Direct Deadbeat Voltage Control with an Actively Damped Inductor-Capacitor Plant Model in an Islanded AC Microgrid

    Directory of Open Access Journals (Sweden)

    Jaehong Kim

    2016-11-01

    Full Text Available A direct deadbeat voltage control design method for inverter-based microgrid applications is proposed in this paper. When the inductor-capacitor (LC filter output voltage is directly controlled using voltage source inverters (VSIs, the plant dynamics exhibit second-order resonant characteristics with a load current disturbance. To effectively damp the resonance caused by the output LC filter, an active damping strategy that does not cause additional energy loss is utilized. The proposed direct deadbeat voltage control law is devised from a detailed, actively damped LC plant model. The proposed deadbeat control method enhances voltage control performance owing to its better disturbance rejection capability than the conventional deadbeat or proportional-integral-based control methods. The most important advantage of the proposed deadbeat control method is that it makes the deadbeat control more robust by bringing discrete closed-loop poles closer to the origin. Simulation and experimental results are shown to verify the enhanced voltage control performance and stability of the proposed voltage control method.

  18. Hittite Microwave公司推出低噪声C波段MMIC VCO

    Institute of Scientific and Technical Information of China (English)

    陈裕权

    2004-01-01

    <正> Hittite Microwave公司开发出一对GaAs/InGaP HBT MMIC压控振荡器(VCO),VCO与电阻、负阻器件、变容二极管及缓冲放大器集成,其工作频率为5.0—6.1GHz。这两种型号为HMC430LP4和HMC431LP4的VCO适用于C波段无线局域网、甚小孔径

  19. Osteotomía tibial alta con placa VCO: Resultados a medio plazo

    OpenAIRE

    Panisello Sebastiá, Juan José; Martínez Martín, Angel Antonio; Herrera Rodríguez, Antonio; Cuenca Espiérrez, Jorge; Canales Cortés, Vicente

    2000-01-01

    Se realiza un estudio retrospectivo de 31 pacientes afectos de genu varo artrósico tratados mediante osteotomía tibial alta y posterior estabilización con placa VCO. Este material permite la movilización y carga precoz de la rodilla, acortando el tiempo de recuperación y las necesidades de rehabilitación. El seguimiento a 4 años muestra una evolución clínica y radiológica satisfactoria en el 80,5% de los pacientes. We report a retrospective análisis of 31 patients presenting varus deformit...

  20. On the Impact of using Public Network Communication Infrastructure for Voltage Control Coordination in Smart Grid Scenario

    DEFF Research Database (Denmark)

    Shahid, Kamal; Petersen, Lennart; Iov, Florin

    2017-01-01

    The high penetration of renewable generation (ReGen) plants in the electric supply necessitates online voltage control support and coordination of ReGen plants in the distribution grid. This imposes a high responsibility on the communication network infrastructure in order to ensure a resilient...... voltage controlled distribution system. A cost effective way to connect the ReGen plants to the control center is to consider the existing public network infrastructure. This paper, therefore, illustrates the impact of using the existing public network communication infrastructure for online voltage...... control support and coordination of ReGen plants in medium voltage distribution systems. Further, by using an exemplary benchmark grid area in Denmark as a base case that includes flexible ReGen plants, we introduce several test cases and evaluate network performance in terms of latencies in the signals...

  1. Design of Ka band MMIC VCO%Ka波段单片压控振荡器的设计

    Institute of Scientific and Technical Information of China (English)

    李鹏亮; 马伟

    2014-01-01

    基于0.25μm GaAs pHEMT工艺设计了Ka波段单片压控振荡器,该压控振荡器采用源极正反馈结构,变容管采用源极和漏极接地的pHEMT管。通过优化输出匹配网络和谐振网络以改善输出功率和相位噪声性能,使用蒙特卡洛成品率分析对本设计的成品率进行分析和改进。版图仿真结果显示:芯片输出频率为24.6~26.3 GHz,输出功率为(10±1)dBm,谐波抑制大于19 dB,芯片尺寸为1.5 mm×1 mm。%A Ka-band MMIC VCO was designed with 0.25 μm GaAs pHEMT process. The source electrode positive feed-back structure is adopted for VCO. The pHEMT whose source electrode and drain electrode are connected to the ground is used for the varactor. The resonance network and the matching network are optimized to improve the output power and the phase noise performance. The yield of the VCO is analyzed and improved by the Monte-Carlo method. The simulation data shows the typical output power of VCO is 10±1 dBm,the output frequency of VCO is 24.6~26.3 GHz,the harmonic suppression is better than 19 dB. The chip size of the MMIC VCO is 1.5 mm×1 mm.

  2. Scaling Radar Measurements for Advanced Algorithms

    Science.gov (United States)

    2010-05-01

    hosted on the DSO. The LVRTS’s voltage controlled oscillator ( VCO ) generates the local oscillator (LO) waveform, with frequency ω0 ≈ 2π(9.8 × 10 9), to...M1 M2 CH0 M1 DSO Ext. Trig. D S O -0 D S O -1 RSA Input VCO PCC TX0 TX1 S0 S1 Local Area Network CH1{ 0f̂ 0f TRC Fig. 1. Connection block diagram for

  3. Virgin Coconut Oil (VCO Enriched with Zn as Immunostimulator for Vaginal Candidiasis Patient

    Directory of Open Access Journals (Sweden)

    HERY WINARSI

    2008-12-01

    Full Text Available Disturbance on the immune system and deficiency of Zn is two factors which often trigger vaginal candidiasis patient. The aim of the research was to study the effect of virgin coconut oil (VCO enriched with Zn to the amount of neutrophil and lymphocyte subset cells, and the level of IL-2 and IgG in vaginal candidiasis patient. Thirty women were grouped into three (ten women in each group: A, B and C, and intervened for two months. Women in A group were intervened with two tablespoon/day; those in B group were intervened with one tablespoon/day; while those in C group served as control (placebo. Blood was sampled at baseline time, one and two months after intervention. Hematological test by Micros-OT was done on a part of blood, and the plasma was used for IL-2 and IgG level tests using ELISA. The virgin coconut oil enriched with Zn maintained the number of neutrophil and NK cells, but increased Tc cells from 521 to 649 cells/mm3, increased Th cells from 1.090 to 1.380 cells/mm3. The enriched VCO also increase level of IL-2 from 0.25313 to 0.27337 pg/ml, while the IgG level changed from equivocal to negative. The recommended dosage was one tablespoon each day.

  4. Giant voltage controlled magnetic anisotropy in heavy metal/ferromagnet/insulator junctions (Conference Presentation)

    Science.gov (United States)

    Kioussis, Nicholas

    2016-10-01

    The realization of the MeRAM is based on the voltage control of the interfacial magnetocrystalline anisotropy (MCA) of heavy-metal/ferromagnet/insulator (HM/FM/I) nanojunctions, where the non-magnetic HM contact electrode (Ta, Pd, Pt, Au) has strong spin-orbit coupling (SOC). Employing ab initio electronic structure calculations we have investigated the effect of electric-field (E-field) and epitaxial strain on the MCA of Ta/FeCo/MgO heterostructure. We predict that uniaxial strain leads to a wide range of interesting voltage behavior of the MCA ranging from linear behavior with positive or negative magnetoelectronic coefficient, to non-monotonic ⋁-shape or inverse-⋀-shape E-field dependence with asymmetric magnetoelectronic coefficients. The calculations reveal that under a 4% compressive strain on MgO reaches the giant value of 1126 fJ/(V.m). The underlying mechanism is the synergistic effects of strain and E-field on the orbital characters, the energy level shifts of the SOC d-states, and the dielectric constant of MgO. These results demonstrate for the first time the feasibility of highly sensitive E-field-controlled MCA through strain engineering, which in turn open a viable pathway towards tailoring magnetoelectric properties for spintronic applications. * nick.kioussis@csun.edu This research was supported by NSF Grant No. ERC-TANMS-1160504

  5. Voltage-Controlled Magnetic Anisotropy in Heavy Metal/Ferromagnet/Insulator-Based Structures

    Science.gov (United States)

    Li, Xiang

    Electric-field assisted writing of magnetic memory that exploits the voltage-controlled magnetic anisotropy (VCMA) effect offers a great potential for high density and low power applications. Magnetoelectric Random Access Memory (MeRAM) has been investigated due to its lower switching current, compared with traditional current-controlled devices utilizing spin transfer torque (STT) or spin-orbit torque (SOT) for magnetization switching. It is of great promise to integrate MeRAM into the advanced CMOS back-end-of-line (BEOL) processes for on-chip embedded applications, and enable non-volatile electronic systems with low static power dissipation and instant-on operation capability. In this thesis, different heavy metal|ferromagnet|insulator-based structures are grown by magnetron sputtering to improve the VCMA effect over the traditional Ta|CoFeB|MgO-based structures. We also established an accurate measurement technique for VCMA characterization. An improved thermal annealing stability of VCMA over 400°C is achieved in Mo|CoFeB|MgO-based structures. In addition, we observed a weak CoFeB thickness dependence of both VCMA coefficient and interfacial perpendicular magnetic anisotropy (PMA) in both Ta|CoFeB|MgO and Mo|CoFeB|MgO-based structures.

  6. Simple voltage-controlled current source for wideband electrical bioimpedance spectroscopy: circuit dependences and limitations

    Science.gov (United States)

    Seoane, F.; Macías, R.; Bragós, R.; Lindecrantz, K.

    2011-11-01

    In this work, the single Op-Amp with load-in-the-loop topology as a current source is revisited. This circuit topology was already used as a voltage-controlled current source (VCCS) in the 1960s but was left unused when the requirements for higher frequency arose among the applications of electrical bioimpedance (EBI). The aim of the authors is not only limited to show that with the currently available electronic devices it is perfectly viable to use this simple VCCS topology as a working current source for wideband spectroscopy applications of EBI, but also to identify the limitations and the role of each of the circuit components in the most important parameter of a current for wideband applications: the output impedance. The study includes the eventual presence of a stray capacitance and also an original enhancement, driving with current the VCCS. Based on the theoretical analysis and experimental measurements, an accurate model of the output impedance is provided, explaining the role of the main constitutive elements of the circuit in the source's output impedance. Using the topologies presented in this work and the proposed model, any electronic designer can easily implement a simple and efficient current source for wideband EBI spectroscopy applications, e.g. in this study, values above 150 kΩ at 1 MHz have been obtained, which to the knowledge of the authors are the largest values experimentally measured and reported for a current source in EBI at this frequency.

  7. Voltage controlled exchange bias in an all-thin-film Cr2O3 based heterostructure

    Science.gov (United States)

    Echtenkamp, Will; Binek, Christian

    2014-03-01

    Spintronics utilizes the electron's spin degree of freedom for an advanced generation of electronic devices with novel functionalities. Controlling magnetism by electrical means has been identified as a key challenge in the field of spintronics, and electric control of exchange bias is one of the most promising routes to address this challenge. Previously, robust isothermal electric control of exchange bias has been achieved near room temperature utilizing a bulk single crystal of Cr2O3. In this study electric control of exchange bias in an all-thin-film system is demonstrated with significant implications for device realization. In particular, voltage controlled switching of exchange bias in a Cr2O3 based magnetoelectric magnetic tunnel junction enables nonvolatile memory storage with virtually dissipationless writing at, or above, room temperature. Additionally, unique physical properties which arise due to the Cr2O3 thin film geometry are highlighted. This project is supported by NSF through MRSEC DMR 0213808, by the NRC/NRI supplement to MRSEC, and by CNFD and C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program.

  8. Adaptive Hierarchical Voltage Control of a DFIG-Based Wind Power Plant for a Grid Fault

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinho; Muljadi, Eduard; Park, Jung-Wook; Kang, Yong Cheol

    2016-11-01

    This paper proposes an adaptive hierarchical voltage control scheme of a doubly-fed induction generator (DFIG)-based wind power plant (WPP) that can secure more reserve of reactive power (Q) in the WPP against a grid fault. To achieve this, each DFIG controller employs an adaptive reactive power to voltage (Q-V) characteristic. The proposed adaptive Q-V characteristic is temporally modified depending on the available Q capability of a DFIG; it is dependent on the distance from a DFIG to the point of common coupling (PCC). The proposed characteristic secures more Q reserve in the WPP than the fixed one. Furthermore, it allows DFIGs to promptly inject up to the Q limit, thereby improving the PCC voltage support. To avert an overvoltage after the fault clearance, washout filters are implemented in the WPP and DFIG controllers; they can prevent a surplus Q injection after the fault clearance by eliminating the accumulated values in the proportional-integral controllers of both controllers during the fault. Test results demonstrate that the scheme can improve the voltage support capability during the fault and suppress transient overvoltage after the fault clearance under scenarios of various system and fault conditions; therefore, it helps ensure grid resilience by supporting the voltage stability.

  9. Intelligent voltage control strategy for three-phase UPS inverters with output LC filter

    Science.gov (United States)

    Jung, J. W.; Leu, V. Q.; Dang, D. Q.; Do, T. D.; Mwasilu, F.; Choi, H. H.

    2015-08-01

    This paper presents a supervisory fuzzy neural network control (SFNNC) method for a three-phase inverter of uninterruptible power supplies (UPSs). The proposed voltage controller is comprised of a fuzzy neural network control (FNNC) term and a supervisory control term. The FNNC term is deliberately employed to estimate the uncertain terms, and the supervisory control term is designed based on the sliding mode technique to stabilise the system dynamic errors. To improve the learning capability, the FNNC term incorporates an online parameter training methodology, using the gradient descent method and Lyapunov stability theory. Besides, a linear load current observer that estimates the load currents is used to exclude the load current sensors. The proposed SFNN controller and the observer are robust to the filter inductance variations, and their stability analyses are described in detail. The experimental results obtained on a prototype UPS test bed with a TMS320F28335 DSP are presented to validate the feasibility of the proposed scheme. Verification results demonstrate that the proposed control strategy can achieve smaller steady-state error and lower total harmonic distortion when subjected to nonlinear or unbalanced loads compared to the conventional sliding mode control method.

  10. A Voltage Controller in Photo-Voltaic System with Battery Storage and Applications

    Directory of Open Access Journals (Sweden)

    Rajendra Aparnathi

    2013-12-01

    Full Text Available This paper work is the new voltage controller in photo-voltaic system for Stand-Alone Applications with battery energy storage. The output of the PV array is unregulated DC supply due to change in weather conditions. The maximum power is tracked with respect to temperature and irradiance levels by using DC-DC converter. The perturbation and observes algorithm is applied for maximum power point tracking (MPPT purpose. This algorithm is selected due to its ability to withstand against any parameter variation and having high efficiency. The solar cell array powers the steady state energy and the battery compensates the dynamic energy in the system. The aim of the control strategy is to control the SEPIC converter and bi-direction DC-DC converter to operate in suitable modes according to the condition of solar cell and battery, so as to coordinate the two sources of solar cell and battery supplying power and ensure the system operates with high efficiency and behaviours with good dynamic performance.

  11. Comparison of Twitch Responses During Current- or Voltage-Controlled Transcutaneous Neuromuscular Electrical Stimulation.

    Science.gov (United States)

    Vargas Luna, José Luis; Krenn, Matthias; Löfler, Stefan; Kern, Helmut; Cortés R, Jorge A; Mayr, Winfried

    2015-10-01

    Neuromuscular electrical stimulation (NMES) is an established method for functional restoration of muscle function, rehabilitation, and diagnostics. In this work, NMES was applied with surface electrodes placed on the anterior thigh to identify the main differences between current-controlled (CC) and voltage-controlled (VC) modes. Measurements of the evoked knee extension force and the myoelectric signal of quadriceps and hamstrings were taken during stimulation with different amplitudes, pulse widths, and stimulation techniques. The stimulation pulses were rectangular and symmetric biphasic for both stimulation modes. The electrode-tissue impedance influences the differences between CC and VC stimulation. The main difference is that for CC stimulation, variation of pulse width and amplitude influences the amount of nerve depolarization, whereas VC stimulation is only dependent on amplitude variations for pulse widths longer than 150 μs. An important remark is that these findings are strongly dependent on the characteristics of the electrode-skin interface. In our case, we used large stimulation electrodes placed on the anterior thigh, which cause higher capacitive effects. The controllability, voltage compliance, and charge characteristics of each stimulation technique should be considered during the stimulators design. For applications that require the activation of a large amount of nerve fibers, VC is a more suitable option. In contrast, if the application requires a high controllability, then CC should be chosen prior to VC.

  12. Activate distributed energy resources' services: Hierarchical voltage controller as an application

    DEFF Research Database (Denmark)

    Han, Xue; Kosek, Anna Magdalena; Gehrke, Oliver

    2014-01-01

    The flexibilities from controllable distributed energy resources (DERs) offer the opportunities to mitigate some of the operation problems in the power distribution grid. The provision of system services requires the aggregation and coordination of their flexibilities, in order to obtain the flex...... the efficient aggregation and dispatch, and it simplifies the optimization complexity; the involvement of DER flexibilities in voltage services can significantly improve the voltage quality and reduce the grid power loss without additional regulating devices....... the flexible capacity of large scale. In this paper, a hierarchical controller is presented to activate the aggregation, and tries to obtain a global optimum of the grid operation. A distribution grid with large penetration of highly varying generation or load is under the risk that the voltage quality...... delivered to the end users is very poor. Hence, a coordinated voltage control function is investigated given such control hierarchy utilizing the flexibilities from the DER units to obtain an optimal voltage profile along the distribution feeder. The results are two folded: the controller enables...

  13. A New Method for a Piezoelectric Energy Harvesting System Using a Backtracking Search Algorithm-Based PI Voltage Controller

    Directory of Open Access Journals (Sweden)

    Mahidur R. Sarker

    2016-09-01

    Full Text Available This paper presents a new method for a vibration-based piezoelectric energy harvesting system using a backtracking search algorithm (BSA-based proportional-integral (PI voltage controller. This technique eliminates the exhaustive conventional trial-and-error procedure for obtaining optimized parameter values of proportional gain (Kp, and integral gain (Ki for PI voltage controllers. The generated estimate values of Kp and Ki are executed in the PI voltage controller that is developed through the BSA optimization technique. In this study, mean absolute error (MAE is used as an objective function to minimize output error for a piezoelectric energy harvesting system (PEHS. The model for the PEHS is designed and analyzed using the BSA optimization technique. The BSA-based PI voltage controller of the PEHS produces a significant improvement in minimizing the output error of the converter and a robust, regulated pulse-width modulation (PWM signal to convert a MOSFET switch, with the best response in terms of rise time and settling time under various load conditions.

  14. Stochastic resonance in a voltage-controlled MEMS-slider: increasing the signal-to-noise ratio with noise

    NARCIS (Netherlands)

    Droogendijk, H.; de Boer, Meint J.; Brookhuis, Robert Anton; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

    2013-01-01

    We demonstrate that, using stochastic resonance (SR) in a voltage-controlled MEMS-slider, the signal-to-noise ratio can be increased by adding white noise. Using a Silicon-on-Insulator (SOI) based process, we realised a slider structure with periodic capacitive structures to obtain tunable unstable

  15. Model of flicker noise effects on phase noise in oscillators

    Science.gov (United States)

    Centurelli, Francesco; Ercolani, Alessandro; Tommasino, Pasquale; Trifiletti, Alessandro

    2003-05-01

    Phase noise models that describe the near-carrier spectrum in an accurate but insightful way are needed, to better optimize the oscillator design. In this paper we present a model to describe the effect of flicker noise sources on the phase noise of an oscillator, that can be applied both to linear oscillators and to nonlinear structures like relaxation and ring oscillators, so extending previous works that considered only the effect of the flicker noise superimposed to the control voltage of a VCO. In the phase noise of an oscillator we can separate the effect of high frequency noise sources, that can be described by a short-time-constant system, and the effect of low frequency noises (mostly flicker sources), described by a system with time constants much slower than the oscillation period. Flicker noise has been considered to cause a change in the circuit bias point; this bias point change can be mapped in a shift of the oscillation frequency by exploiting Barkhausen conditions (for linear oscillators) or obtaining this link by simulations. The power spectral density of the oscillator can then be obtained as the probability distribution of the oscillation frequency, starting from the flicker noise probability distribution. If the effect of high frequency noise sources is also taken into account, the overall oscillator spectrum can be obtained as a convolution of the spectrum due to flicker sources with the Lorentzian-shaped spectrum due to white noise sources, in analogy with the description of inhomogeneous broadening of laser linewidth.

  16. Design of Frequency Doubling VCO for Bluetooth Transceiver%一种用于Bluetooth发接器的倍频式VCO

    Institute of Scientific and Technical Information of China (English)

    苏彦锋; 衣晓峰; 朱臻; 洪志良

    2004-01-01

    介绍了一种适用于Bluetooth发接器的,可以单片集成的倍频式压控振荡器(VCO).这种VCO由两部分组成,主VCO的振荡频率是所需本振频率的一半,然后采用"注入锁频"原理对主VCO的振荡频率进行倍频以产生本振信号.主VCO和倍频电路都使用了片上集成螺旋电感,调谐用的变容元件使用PMOS晶体管实现.经过版图设计和后仿真,在TSMC 0.35 μm数字COMS工艺,3.3 V电源电压下,该VCO在2.4 GHz中心频率附近可以达到的相位噪声指标为-125 dBc/Hz(600 kHz),在输出摆幅为600 mVp-p时,功耗为22 mW.

  17. Model of orbital populations for voltage-controlled magnetic anisotropy in transition-metal thin films

    Science.gov (United States)

    Zhang, Jia; Lukashev, Pavel V.; Jaswal, Sitaram S.; Tsymbal, Evgeny Y.

    2017-07-01

    Voltage-controlled magnetic anisotropy (VCMA) is an efficient way to manipulate the magnetization states in nanomagnets and is promising for low-power spintronic applications. The underlying physical mechanism for VCMA is known to involve a change in the d orbital occupation on the transition-metal interface atoms with an applied electric field. However, a simple qualitative picture of how this occupation controls the magnetocrystalline anisotropy (MCA) and even why in certain cases the MCA has the opposite sign remains elusive. In this paper, we exploit a simple model of orbital populations to elucidate a number of features typical for the interface MCA, and the effect of the electric field on it, for 3 d transition-metal thin films used in magnetic tunnel junctions. We find that in all considered cases, including the Fe(001) surface, clean F e1 -xC ox(001 ) /MgO interface, and oxidized Fe(001)/MgO interface, the effects of alloying and the electric field enhance the MCA energy with electron depletion, which is largely explained by the occupancy of the minority-spin dx z ,y z orbitals. However, the hole-doped Fe(001) exhibits an inverse VCMA in which the MCA enhancement is achieved when electrons are accumulated at the Fe (001)/MgO interface with the applied electric field. In this regime, we predict a significantly enhanced VCMA that exceeds 1 pJ/Vm. Realizing this regime experimentally may be favorable for the practical purpose of voltage-driven magnetization reversal.

  18. Design of Low Phase-Noise Integrated Broadband VCO%集成宽带VCO的低相噪设计

    Institute of Scientific and Technical Information of China (English)

    姚立华; 郭文胜

    2009-01-01

    The design methods and ideas of the low phase-noise integrated broadband VCO was presented by analyzing the concept and principle of VCO phase noise. Theoretical analysis was made and mathematical model was established, and it was realized through simulation and optimization design by related software. The obtained phase-noise index of the entire frequency band of the integrated broadband VCO was given. The series of the low phase-noise integrated VCO is of great benefit to system engineers in circuit design. Currently, the designed low phase-noise VCO is widely used in various electronic systems. It plays a significant role in domestic manufacturing key circuit for electronic systems with high performance.%从VCO的相位噪声概念及原理分析入手,论述了集成宽带压控振荡器低相噪的设计方法和设计思路,进行了理论分析和数学模拟,并通过利用相关软件进行仿真、优化设计.获得了低相噪声的宽带振荡器,并给出了各频段集成宽带VCO最终达到的相位噪声指标.低相噪声集成VCO系列产品的成功研制极大地方便了系统设计师的电路设计,该自主研制的低相噪VCO已广泛应用于多种电子系统中,对系统关键电路的国产化、高性能化有着重要意义.

  19. Modeling VCO with Noise Using Verilog- AMS%基于Verilog-AMS的VCO噪声建模

    Institute of Scientific and Technical Information of China (English)

    尹勇生; 陈志明; 邓红辉

    2007-01-01

    压控振荡器(VCO)是锁相环(PLL)的关键部件,目前多数研究都着重于VCO的电路级设计.采用VerologAMS语言对VCO进行行为建模,同时加入噪声模型,行为级设计中体现噪声.对比有噪声和无噪声的VCO行为模型,利用Cadence Spectre仿真引擎对2个模型进行了验证,将内嵌VCO行为模型的PLL系统与电路级PLL系统做了对比分析,结论为添加噪声的VCO行为模型更准确,更接近晶体管级电路,对仿真的速度与精度做了较好的折中.

  20. A 2GHz, 17% tuning range quadrature CMOS VCO with high figure–of–merit and 0.6° phase error

    DEFF Research Database (Denmark)

    Andreani, Pietro

    2002-01-01

    This paper presents a quadrature VCO implemented in a standard 0.35µm CMOS process. The VCO draws 16mA from a 1.3V power supply, can be tuned between 1.91 GHz and 2.27GHz, and displays a phase noise of -140dBc/Hz or less at 3MHz offset frequency from the carrier, for a minimum phase-noise figure......-of-merit of 184 dB. The maximum departure from quadrature between the VCO phases is 0.6°....

  1. Fermi resonance and solvent dependence of the vC=O frequency shifts of Raman spectra: cyclohexanone and 2-cyclohexene-1-one

    CERN Document Server

    Nam, S I; Lee, M S; Jung, Y M

    2001-01-01

    The carbonyl stretching vibration, vC=O of 2-cyclohexene-1-one , is in Fermi resonance with a combination tone. The amount of Fermi resonance interaction between these two modes is dependent upon the amount of solute/solvent interaction due to hydrogen bonding between the carbonyl oxygen and the solvent proton. The corrected vC=O frequency of 2-cyclohexene-1-one occurs at a lower frequency than the observed vC=O mode of cyclohexanone, possibly caused by expanded conjugation effects. The carbonyl stretching modes of cyclic ketones were also affected by interaction with the ROH/CCl sub 4 mixed solvent system.

  2. 一种双带宽UHF主从耦合式LC VCO%UHF Master-Slave Coupled LC VCO with Two Bandwidthes

    Institute of Scientific and Technical Information of China (English)

    马淋军; 杨宁; 周晓迪; 成立; 严雪萍

    2009-01-01

    为了满足无线通信系统应用需要,设计了一种主从耦合式LC压控振荡器(VCO).基于0.18 μm CMOS标准工艺,由一个5 GHz主VCO和两个起分频作用的从VCO组成,其中主VCO选用PMOS考毕兹差分振荡结构,在两个互补交叉耦合的从VCO的输出端之间设置有注入式NMOS器件以达到分频的目的.仿真及硬件电路实验结果表明,在1.8 V低电源电压下,5 GHz主VCO的调谐范围为4.68~5.76 GHz,2.5 GHz从VCO的调谐范围为2.32~2.84 GHz;在1 MHz的偏频下,5 GHz主VCO的相位噪声为118.2 dBc/Hz,2.5 GHz从VCO的相位噪声为124.4 dBc/Hz.另外,主从VCO的功耗分别为6.8 mW和7.9 mW,因此特别适用于低功耗、超高频短距离无线通信系统中.

  3. HYBRID EVOLUTIONARY ALGORITHMS FOR FREQUENCY AND VOLTAGE CONTROL IN POWER GENERATING SYSTEM

    Directory of Open Access Journals (Sweden)

    A. Soundarrajan

    2010-10-01

    Full Text Available Power generating system has the responsibility to ensure that adequate power is delivered to the load, both reliably and economically. Any electrical system must be maintained at the desired operating level characterized by nominal frequency and voltage profile. But the ability of the power system to track the load is limited due to physical and technical consideration. Hence, a Power System Control is required to maintain a continuous balance between power generation and load demand. The quality of power supply is affected due to continuous and random changes in load during the operation of the power system. Load Frequency Controller (LFC and Automatic Voltage Regulator (AVR play an important role in maintaining constant frequency and voltage in order to ensure the reliability of electric power. The fixed gain PID controllers used for this application fail to perform under varying load conditions and hence provide poor dynamic characteristics with large settling time, overshoot and oscillations. In this paper, Evolutionary Algorithms (EA like, Enhanced Particle Swarm Optimization (EPSO, Multi Objective Particle Swarm Optimization (MOPSO, and Stochastic Particle Swarm Optimization (SPSO are proposed to overcome the premature convergence problem in a standard PSO. These algorithms reduce transient oscillations and also increase the computational efficiency. Simulation results demonstrate that the proposed controller adapt themselves appropriate to varying loads and hence provide better performance characteristics with respect to settling time, oscillations and overshoot.

  4. A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain;

    2015-01-01

    This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VSC-HVDC......) converter station. Due to limited short circuit power contribution from power electronic interfaced variable speed wind generators and with the onshore main grid decoupled by the HVDC link, the offshore AC grid becomes more vulnerable to dynamic voltage events. Therefore, a short circuit fault...... in the offshore AC Grid is likely to have significant implications on the voltage of the offshore AC grid, hence on the power flow to the onshore mainland grid. The proposed CVCS integrates individual local reactive power control of wind turbines and of the HVDC converter with the secondary voltage controller...

  5. Modeling and Design of DC Boost and AC Side Voltage Controllers in Asymmetrical Γ-Source Inverter

    Directory of Open Access Journals (Sweden)

    Seyed Mahyar Mehdizadeh Moghadam

    2014-07-01

    Full Text Available In this paper a control system is proposed to simultaneously control the voltage boost and output voltage of assymetrical Γ-Source Inverters. Dynamic model of the system is used to design the controllers. Voltage boost on assymetrical Γ-Source Inverters is done by voltage control of impedance network capacitor and the regulation of inverter shoot through duty cycle. Since the stability margin of the system is low due to the right half plane zero in its dynamic model, the design of fast control system is impossible therefore a nonlinear feedforward control loop is used to faster the control system performance. Linear control system is used to control the AC-side in synchrony reference frame such that the AC voltage control system regulates the output voltage by means of modulation index regulation. The proposed control system performance is investigated by simulation in MATLAB/Simulink

  6. Dual-harmonic auto voltage control for the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    Fumihiko Tamura

    2008-07-01

    Full Text Available The dual-harmonic operation, in which the accelerating cavities are driven by the superposition of the fundamental and the second harmonic rf voltage, is useful for acceleration of the ultrahigh intensity proton beam in the rapid cycling synchrotron (RCS of Japan Proton Accelerator Research Complex (J-PARC. However, the precise and fast voltage control of the harmonics is necessary to realize the dual-harmonic acceleration. We developed the dual-harmonic auto voltage control system for the J-PARC RCS. We describe details of the design and the implementation. Various tests of the system are performed with the RCS rf system. Also, a preliminary beam test has been done. We report the test results.

  7. Single-Stage Low-Power Quadrature RF Receiver Front-End: The LMV Cell

    DEFF Research Database (Denmark)

    Liscidini, Antonio; Mazzanti, Andrea; Tonietto, Riccardo;

    2006-01-01

    This paper presents the first quadrature RF receiver front-end where, in a single stage, low-noise amplifier (LNA), mixer and voltage-controlled oscillator (VCO) share the same bias current. The new structure exploits the intrinsic mixing functionality of a classical LC-tank oscillator providing...

  8. Being flexible: the voltage-controllable activation gate of Kv channels

    Directory of Open Access Journals (Sweden)

    Alain J. Labro

    2012-09-01

    Full Text Available Kv channels form voltage-dependent potassium selective pores in the outer cell membrane and are composed out of four -subunits, each having six membrane-spanning -helices (S1-S6. The -subunits tetramerize such that the S5-S6 pore domains co-assemble into a centrally located K+ pore which is surrounded by four operational voltage sensing domains (VSD that are each formed by the S1-S4 segments. Consequently, each subunit is capable of responding to changes in membrane potential and dictates whether the pore should be conductive or not. K+ permeation through the pore can be sealed off by two separate gates in series: (a at the inner S6 bundle crossing (BC gate and (b at the level of the selectivity-filter (SF gate located at the extracellular entrance of the pore. Within the last years a general consensus emerged that a direct communication between the S4S5-linker and the bottom part of S6 (S6c constitutes the coupling with the VSD thus making the BC gate the main voltage-controllable activation gate. While the BC gate listens to the VSD, the SF changes its conformation depending on the status of the BC gate. Through the eyes of an entering K+ ion, the operation of the BC gate apparatus can be compared with the iris-like motion of the diaphragm from a camera whereby its diameter widens. Two main gating motions have been proposed to create this BC gate widening: (1 tilting of the helix whereby the S6 converts from a straight -helix to a tilted one or (2 swiveling of the S6c whereby the S6 remains bent. Such motions require a flexible hinge that decouples the pre- and post-hinge segment. Roughly at the middle of the S6 there exists a highly conserved glycine residue and a tandem proline motif that seem to fulfill the role of a gating hinge which allows for tilting/swiveling/rotations of the post-hinge S6 segment. In this review we delineate our current view on the operation of the BC gate for controlling K+ permeation in Kv channels.

  9. Voltage control of magnetic anisotropy in epitaxial Ru/Co2FeAl/MgO heterostructures

    Science.gov (United States)

    Wen, Zhenchao; Sukegawa, Hiroaki; Seki, Takeshi; Kubota, Takahide; Takanashi, Koki; Mitani, Seiji

    2017-01-01

    Voltage control of magnetic anisotropy (VCMA) in magnetic heterostructures is a key technology for achieving energy-efficiency electronic devices with ultralow power consumption. Here, we report the first demonstration of the VCMA effect in novel epitaxial Ru/Co2FeAl(CFA)/MgO heterostructures with interfacial perpendicular magnetic anisotropy (PMA). Perpendicularly magnetized tunnel junctions with the structure of Ru/CFA/MgO were fabricated and exhibited an effective voltage control on switching fields for the CFA free layer. Large VCMA coefficients of 108 and 139 fJ/Vm for the CFA film were achieved at room temperature and 4 K, respectively. The interfacial stability in the heterostructure was confirmed by repeating measurements. Temperature dependences of both the interfacial PMA and the VCMA effect were also investigated. It is found that the temperature dependences follow power laws of the saturation magnetization with an exponent of ~2, where the latter is definitely weaker than that of conventional Ta/CoFeB/MgO. The significant VCMA effect observed in this work indicates that the Ru/CFA/MgO heterostructure could be one of the promising candidates for spintronic devices with voltage control. PMID:28332569

  10. Adaptive Q–V Scheme for the Voltage Control of a DFIG-Based Wind Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinho; Seok, Jul-Ki; Muljadi, Eduard; Kang, Yong Cheol

    2016-05-01

    Wind generators within a wind power plant (WPP) will produce different amounts of active power because of the wake effect, and therefore, they have different reactive power capabilities. This paper proposes an adaptive reactive power to the voltage (Q-V) scheme for the voltage control of a doubly fed induction generator (DFIG)-based WPP. In the proposed scheme, the WPP controller uses a voltage control mode and sends a voltage error signal to each DFIG. The DFIG controller also employs a voltage control mode utilizing the adaptive Q-V characteristics depending on the reactive power capability such that a DFIG with a larger reactive power capability will inject more reactive power to ensure fast voltage recovery. Test results indicate that the proposed scheme can recover the voltage within a short time, even for a grid fault with a small short-circuit ratio, by making use of the available reactive power of a WPP and differentiating the reactive power injection in proportion to the reactive power capability. This will, therefore, help to reduce the additional reactive power and ensure fast voltage recovery.

  11. Voltage control of magnetic anisotropy in epitaxial Ru/Co2FeAl/MgO heterostructures

    Science.gov (United States)

    Wen, Zhenchao; Sukegawa, Hiroaki; Seki, Takeshi; Kubota, Takahide; Takanashi, Koki; Mitani, Seiji

    2017-03-01

    Voltage control of magnetic anisotropy (VCMA) in magnetic heterostructures is a key technology for achieving energy-efficiency electronic devices with ultralow power consumption. Here, we report the first demonstration of the VCMA effect in novel epitaxial Ru/Co2FeAl(CFA)/MgO heterostructures with interfacial perpendicular magnetic anisotropy (PMA). Perpendicularly magnetized tunnel junctions with the structure of Ru/CFA/MgO were fabricated and exhibited an effective voltage control on switching fields for the CFA free layer. Large VCMA coefficients of 108 and 139 fJ/Vm for the CFA film were achieved at room temperature and 4 K, respectively. The interfacial stability in the heterostructure was confirmed by repeating measurements. Temperature dependences of both the interfacial PMA and the VCMA effect were also investigated. It is found that the temperature dependences follow power laws of the saturation magnetization with an exponent of ~2, where the latter is definitely weaker than that of conventional Ta/CoFeB/MgO. The significant VCMA effect observed in this work indicates that the Ru/CFA/MgO heterostructure could be one of the promising candidates for spintronic devices with voltage control.

  12. Voltage-Controlled Square/Triangular Wave Generator with Current Conveyors and Switching Diodes

    Directory of Open Access Journals (Sweden)

    Martin Janecek

    2012-12-01

    Full Text Available A novel relaxation oscillator based on integrating the diode-switched currents and Schmitt trigger is presented. It is derived from a known circuit with operational amplifiers where these active elements were replaced by current conveyors. The circuit employs only grounded resistances and capacitance and is suitable for high frequency square and triangular signal generation. Its frequency can be linearly and accurately controlled by voltage that is applied to a high-impedance input. Computer simulation with a model of a manufactured conveyor prototype verifies theoretic assumptions.

  13. Design And Investigation Of 65 Nm Rf Cmos Technology Lc-Vco’s

    Directory of Open Access Journals (Sweden)

    Vytautas Mačaitis

    2014-05-01

    Full Text Available In this paper, two LC Voltage-Controlled Oscillators (LC-LC-VCO1 and LC-VCO2 are designed using TSMC 65 nm LP/MS/RF CMOS technology. Two arrays, one of which is a 6-bit capacitor array and the other – an array of MOS varactors, provide a wide LC-VCO frequency tuning range. Post-layout simulation results unveiled that at 1.8 V supply voltage the tuning range of LC-VCO1 spans from 5.17 GHz to 6.76 GHz and for LC-VCO2 the range spans from 6.33 GHz to 8.08 GHz. The phase noise at 1 MHz offset frequency is about −123.1 dBc/Hz for LC-VCO1 and −121.6 dBc/Hz for LC-VCO2. The power dissipation at maximum carrier is 30.47 mW for LC-VCO1 and 30.5 mW for LC-VCO2. The layout area is 285×335 μm and 255×305 μm, respectively for LC-VCO1 and LC-VCO2.

  14. A CMOS LC VCO with 3.2~6.1GHz Tuning Range%频率覆盖3.2~6.1 GHz的CMOS LC VCO

    Institute of Scientific and Technical Information of China (English)

    宁彦卿; 池保勇; 王志华; 陈弘毅

    2007-01-01

    The design and implementation of a CMOS LC VCO with 3.2~6.1 GHz tuning range are presented. This is achieved by enhancing the tuning capability of the binary-weighted band-switching MIM capacitor. The circuit has been implemented in a 0.18μm RF/Mixed-Signal CMOS process. The measured phase noise is - 101.67dBc/Hz at 1MHz offset from a 5.5GHz carrier,and the VCO core draws 9. 69mA current from a 1.8V supply.%通过提高MIM电容的调整范围,实现了一个覆盖3.2~6.1 GHz的CMOS LC VCO.该VCO使用0.18μm射频CMOS工艺制作,芯片面积约为1260μm×670μm.当输出5.5GHz时,VCO内核消耗功率为17.5mW;在100kHz频偏处的相位噪声是~101.67dBc/Hz.

  15. A PLL Exploiting Sub-Sampling of the VCO Output to Reduce In-band Phase Noise

    NARCIS (Netherlands)

    Gao, X.; Klumperink, Eric A.M.; Boshali, Mounir; Nauta, Bram

    2009-01-01

    Abstract— In this paper, we present a 2.2-GHz low jitter PLL based on sub-sampling. It uses a phase-detector/charge-pump (PD/CP) that sub-samples the VCO output with the reference clock. In contrast to what happens in a classical PLL, the PD/CP noise is not multiplied by N2 in this sub-sampling PLL.

  16. Pengaruh VCO terhadap hitung jenis leukosit, kadar glukosa dan kreatinin darah Mus musculus Balb/c hiperglikemi dan tersensitisasi ovalbumin

    Directory of Open Access Journals (Sweden)

    NOOR SOESANTI HANDAJANI

    2009-05-01

    Full Text Available Handajani NS, Dharmawan R. 2009. Pengaruh VCO terhadap hitung jenis leukosit, kadar glukosa dan kreatinin darah Mus musculus Balb/c hiperglikemi dan tersensitisasi ovalbumin. Bioteknologi 6: 1-10. Obat-obatan kimia dan insulin dapat menurunkan kadar glukosa darah pada pasien dengan efek samping hiperglikemi makro vaskular. Diabetes dan insiden alergi dipengaruhi kualitas dan kuantitas leukosit. Asam laurat dalam VCO dilaporkan menurunkan tingkat glukosa darah pada kejadian diabetes dan beberapa insiden alergi. Tujuan penelitian ini adalah mengetahui pengaruh VCO pada tingkat glukosa darah, diferensial leukosit dan kadar kreatinin pada mencit hiperglikemi dan normoglicemic tersensitisasi ovalbumin. Empat puluh lima (45 mencit Mus musculus Balb/c jantan dengan berat rata-rata 35 g dibagi menjadi 9 kelompok dengan 5 ulangan, yaitu 4 kelompok non aloksan dan 5 kelompok hiperglikemi yang diinduksi aloksan, Pada hari ke-22 sampai ke-36, mereka disensitisasi dengan ovalbumin sebagai penyebab alergi. Sampel darah diperoleh dari vena orbital menggunakan heparin sebagai anti koagulan, kadar glukosa darah diukur dengan metode GOD sebanyak 6 kali, pada hari ke-1, 4, 18, 22, 32 dan 37, kemudian diuji dengan ANAVA yang diikuti oleh DMRT 0,05 untk mengetahui tingkat perbedaan antar perlakuan. Pada hari ke-37, diferensial leukosit dan tingkat kreatinin darah ditentukan, lalu dibandingkan dengan nilai normal. Hasil penelitian menunjukkan bahwa dalam hitungan diferensial leukosit mencit hiperglikemi, persentase neutrofil jauh lebih rendah daripada nilai normal (3.22%, dan persentase limfosit jauh lebih tinggi daripada nilai normal (94.54%. Konsumsi 0.003 mL/35 g VCO lebih dari 18 hari menurunkan kadar glukosa darah pada mencit hiperglikemi, menurunkan persentase basophile pada mencit tersensitisasi ovalbumin, normalisasi persentase neutrophile tidak meningkatkan tingkat kreatinin darah.

  17. A PLL Exploiting Sub-Sampling of the VCO Output to Reduce In-band Phase Noise

    NARCIS (Netherlands)

    Gao, Xiang; Klumperink, Eric A.M.; Boshali, Mounir; Nauta, Bram

    2009-01-01

    Abstract— In this paper, we present a 2.2-GHz low jitter PLL based on sub-sampling. It uses a phase-detector/charge-pump (PD/CP) that sub-samples the VCO output with the reference clock. In contrast to what happens in a classical PLL, the PD/CP noise is not multiplied by N2 in this sub-sampling PLL.

  18. Modeling and Design of DC Boost and AC Side Voltage Controllers in Asymmetrical Γ-Source Inverter

    OpenAIRE

    2014-01-01

    In this paper a control system is proposed to simultaneously control the voltage boost and output voltage of assymetrical Γ-Source Inverters. Dynamic model of the system is used to design the controllers. Voltage boost on assymetrical Γ-Source Inverters is done by voltage control of impedance network capacitor and the regulation of inverter shoot through duty cycle. Since the stability margin of the system is low due to the right half plane zero in its dynamic model, the design of fast contro...

  19. Challenge of Primary Voltage Control in Large Scale Wind Integrated Power System: A Danish Power System Case Study

    DEFF Research Database (Denmark)

    Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul

    2013-01-01

    Grid integration of Renewable Energy (RE) at large scale poses vast majority of challenges to secure and stable operation of Power System. This paper presents the challenge of short circuit power and primary voltage control of wind integrated power system where majority of conventional generators...... are replaced by wind generators. The impact of large scale wind integration on fast reactive power support is studied in this paper. Considering both technical and economic aspects, alternatives to address the challenge of dynamic voltage support have also been demonstrated in this paper. A case study...

  20. Direct fabrication of electrically functional microstructures by fully voltage-controlled electrohydrodynamic jet printing of silver nano-ink

    Science.gov (United States)

    Wang, Ke; Stark, John P. W.

    2010-06-01

    We report electrohydrodynamic jet (E-jet) printing of a commercialised silver nano-ink in fully voltage-controlled fashion. Metallic pads and conducting tracks with hundred-micron feature size were drop-on-demands produced on Si substrates. Layer-by-layer printing was further performed, demonstrating a capability in creating 3D multistructures. Planar pattern with a large inductance of 2.5 μH and an excellent resistivity of 4.2×10-8 Ω m was fabricated, showing a true inductive device. Our result demonstrates a feasibility of E-jet printing in the application of smart electronic devices fabrication.

  1. Voltage-controlled magnetization switching in MRAMs in conjunction with spin-transfer torque and applied magnetic field

    Science.gov (United States)

    Munira, Kamaram; Pandey, Sumeet C.; Kula, Witold; Sandhu, Gurtej S.

    2016-11-01

    Voltage-controlled magnetic anisotropy (VCMA) effect has attracted a significant amount of attention in recent years because of its low cell power consumption during the anisotropy modulation of a thin ferromagnetic film. However, the applied voltage or electric field alone is not enough to completely and reliably reverse the magnetization of the free layer of a magnetic random access memory (MRAM) cell from anti-parallel to parallel configuration or vice versa. An additional symmetry-breaking mechanism needs to be employed to ensure the deterministic writing process. Combinations of voltage-controlled magnetic anisotropy together with spin-transfer torque (STT) and with an applied magnetic field (Happ) were evaluated for switching reliability, time taken to switch with low error rate, and energy consumption during the switching process. In order to get a low write error rate in the MRAM cell with VCMA switching mechanism, a spin-transfer torque current or an applied magnetic field comparable to the critical current and field of the free layer is necessary. In the hybrid processes, the VCMA effect lowers the duration during which the higher power hungry secondary mechanism is in place. Therefore, the total energy consumed during the hybrid writing processes, VCMA + STT or VCMA + Happ, is less than the energy consumed during pure spin-transfer torque or applied magnetic field switching.

  2. Direct measurement of voltage-controlled reversal of the antiferromagnetic spin structure in magnetoelectric Cr2O3

    Science.gov (United States)

    Wang, Junlei; Binek, Christian

    The frequency dependence of the electric field induced magneto-optical Faraday effect is investigated in the magnetoelectric antiferromagnet chromia. Two electrically induced Faraday signals superimpose in proportion to the linear magnetoelectric susceptibility and the antiferromagnetic order parameter. The relative strength of these contributions is determined by the frequency of the probing light beam. It allows tuning the Faraday signal between extreme characteristics which follow the temperature dependence of the magnetoelectric susceptibility or solely that of the antiferromagnetic order parameter. The frequency dependence is analyzed in terms of electric dipole transitions of perturbed Cr3 + crystal-field states. The results lead to a table-top set-up allowing to measure voltage-controlled selection and temperature dependence of the antiferromagnetic order parameter. The Faraday rotation per applied voltage is independent of the sample thickness making the method scalable and versatile for thin film investigations. Scalability, compactness, and simplicity of the data analysis combined with low photon flux requirements make the Faraday approach advantageous for the investigation of the otherwise difficult to access voltage-controlled switching of antiferromagnetic domain states in magnetoelectric thin films. This project is supported by NRI via CNFD through tasks SRC 2398.001 and 2587.001, by C-SPIN, a SRC program, sponsored by MARCO and DARPA, and by NSF through Nebraska MRSEC DMR-1420645.

  3. Enhanced voltage-controlled magnetic anisotropy in magnetic tunnel junctions with an MgO/PZT/MgO tunnel barrier

    Science.gov (United States)

    Chien, Diana; Li, Xiang; Wong, Kin; Zurbuchen, Mark A.; Robbennolt, Shauna; Yu, Guoqiang; Tolbert, Sarah; Kioussis, Nicholas; Khalili Amiri, Pedram; Wang, Kang L.; Chang, Jane P.

    2016-03-01

    Compared with current-controlled magnetization switching in a perpendicular magnetic tunnel junction (MTJ), electric field- or voltage-induced magnetization switching reduces the writing energy of the memory cell, which also results in increased memory density. In this work, an ultra-thin PZT film with high dielectric constant was integrated into the tunneling oxide layer to enhance the voltage-controlled magnetic anisotropy (VCMA) effect. The growth of MTJ stacks with an MgO/PZT/MgO tunnel barrier was performed using a combination of sputtering and atomic layer deposition techniques. The fabricated MTJs with the MgO/PZT/MgO barrier demonstrate a VCMA coefficient, which is ˜40% higher (19.8 ± 1.3 fJ/V m) than the control sample MTJs with an MgO barrier (14.3 ± 2.7 fJ/V m). The MTJs with the MgO/PZT/MgO barrier also possess a sizeable tunneling magnetoresistance (TMR) of more than 50% at room temperature, comparable to the control MTJs with an MgO barrier. The TMR and enhanced VCMA effect demonstrated simultaneously in this work make the MgO/PZT/MgO barrier-based MTJs potential candidates for future voltage-controlled, ultralow-power, and high-density magnetic random access memory devices.

  4. Capacitive Power Transfer

    Science.gov (United States)

    2010-12-15

    PD3S160 C = 38 pF, VF = 0.58 V @ 0.7 A Table 6: Suggested LED driver components. 28 KVCORF KT vf f KI Measured Current it IOUT IREF + Loop Filter VCO ...presented in Figure 15. A voltage controlled oscillator ( VCO ) with gain KV CO in Hertz per volt is used to synthesize the frequency f (ω = 2πf) that...error signal is approximately 50µs. The simulated loop gain is 60. The simulated VCO frequency is 3.3 MHz. The discrepancy between the reported error

  5. Automatic oscillator frequency control system

    Science.gov (United States)

    Smith, S. F. (Inventor)

    1985-01-01

    A frequency control system makes an initial correction of the frequency of its own timing circuit after comparison against a frequency of known accuracy and then sequentially checks and corrects the frequencies of several voltage controlled local oscillator circuits. The timing circuit initiates the machine cycles of a central processing unit which applies a frequency index to an input register in a modulo-sum frequency divider stage and enables a multiplexer to clock an accumulator register in the divider stage with a cyclical signal derived from the oscillator circuit being checked. Upon expiration of the interval, the processing unit compares the remainder held as the contents of the accumulator against a stored zero error constant and applies an appropriate correction word to a correction stage to shift the frequency of the oscillator being checked. A signal from the accumulator register may be used to drive a phase plane ROM and, with periodic shifts in the applied frequency index, to provide frequency shift keying of the resultant output signal. Interposition of a phase adder between the accumulator register and phase plane ROM permits phase shift keying of the output signal by periodic variation in the value of a phase index applied to one input of the phase adder.

  6. Neurodynamic oscillators

    Science.gov (United States)

    Espinosa, Ismael; Gonzalez, Hortensia; Quiza, Jorge; Gonazalez, J. Jesus; Arroyo, Ruben; Lara, Ritaluz

    1995-01-01

    Oscillation of electrical activity has been found in many nervous systems, from invertebrates to vertebrates including man. There exists experimental evidence of very simple circuits with the capability of oscillation. Neurons with intrinsic oscillation have been found and also neural circuits where oscillation is a property of the network. These two types of oscillations coexist in many instances. It is nowadays hypothesized that behind synchronization and oscillation there is a system of coupled oscillators responsible for activities that range from locomotion and feature binding in vision to control of sleep and circadian rhythms. The huge knowledge that has been acquired on oscillators from the times of Lord Rayleigh has made the simulation of neural oscillators a very active endeavor. This has been enhanced with more recent physiological findings about small neural circuits by means of intracellular and extracellular recordings as well as imaging methods. The future of this interdisciplinary field looks very promising; some researchers are going into quantum mechanics with the idea of trying to provide a quantum description of the brain. In this work we describe some simulations using neuron models by means of which we form simple neural networks that have the capability of oscillation. We analyze the oscillatory activity with root locus method, cross-correlation histograms, and phase planes. In the more complicated neural network models there is the possibility of chaotic oscillatory activity and we study that by means of Lyapunov exponents. The companion paper shows an example of that kind.

  7. Design of Neutral-Point Voltage Controller of a Three-level NPC Inverter with Small DC-Link Capacitors

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

    2013-01-01

    A Neutral-Point-Clamped (NPC) three-level inverter with small dc-link capacitors is presented in this paper. The inverter requires zero average neutral-point current for stable neutral-point voltage. The small dc-link capacitors may not maintain capacitor voltage balance, even with zero neutral-point...... current. This may happen due to nonlinearities present in the circuit. This requires a fast control of the neutral-point voltage. A simple carrier based modulation strategy which allows modeling of the neutral-point voltage dynamics as a continuous function of power drawn from the inverter is proposed....... This continuous model shows that the neutral-point current is proportional to the power drawn from the inverter, and it enables the use of well established classical control theory for the neutral-point voltage controller design. A simple PI (proportional integral) controller is designed for the neutral-point...

  8. Capacity determination of a battery energy storage system based on the control performance of load leveling and voltage control

    Directory of Open Access Journals (Sweden)

    Satoru Akagi

    2016-01-01

    Full Text Available This paper proposes a method to determine the combined energy (kWh and power (kW capacity of a battery energy storage system and power conditioning system capacity (kVA based on load leveling and voltage control performances. Through power flow calculations, a relationship between the capacity combination and the control performance is identified and evaluated. A tradeoff relationship between the capacity combination and control performance is confirmed, and the proper capacity combination for operation is determined based on the evaluated relationship. In addition, the control performance of the capacity combination is evaluated through the power flow calculation, confirming that the proposed method is effective for determining the optimized capacity combination.

  9. Low start-up voltage dc–dc converter with negative voltage control for thermoelectric energy harvesting

    Directory of Open Access Journals (Sweden)

    Pui-Sun Lei

    2015-01-01

    Full Text Available This Letter presents a low start-up voltage dc–dc converter for low-power thermoelectric systems which uses a native n-type MOS transistor as the start-up switch. The start-up voltage of the proposed converter is 300 mV and the converter does not need batteries to start up. The negative voltage control is proposed to reduce the leakage current caused by native n-type transistor and increase the efficiency. The proposed converter was designed using standard 0.18 µm CMOS process with chip size of 0.388 mm^2. The peak efficiency is 63% at load current of 1.5 mA. The proposed converter provides output voltage >1 V at maximum load current of 3.2 mA.

  10. Voltage-controlled magnetic anisotropy in Fe|MgO tunnel junctions studied by x-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, Shinji, E-mail: miwa@mp.es.osaka-u.ac.jp; Matsuda, Kensho; Tanaka, Kazuhito; Goto, Minori; Suzuki, Yoshishige [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kotani, Yoshinori; Nakamura, Tetsuya [Japan Synchrotron Radiation Research Institute/SPring-8, Sayo, Hyogo 679-5198 (Japan)

    2015-10-19

    In this study, voltage-controlled magnetic anisotropy (VCMA) in Fe|MgO tunnel junctions was investigated via the magneto-optical Kerr effect, soft x-ray absorption spectroscopy, and magnetic circular dichroism spectroscopy. The Fe|MgO tunnel junctions showed enhanced perpendicular magnetic anisotropy under external negative voltage, which induced charge depletion at the Fe|MgO interface. Despite the application of voltages of opposite polarity, no trace of chemical reaction such as a redox reaction attributed to O{sup 2−} migration was detected in the x-ray absorption spectra of the Fe. The VCMA reported in the Fe|MgO-based magnetic tunnel junctions must therefore originate from phenomena associated with the purely electric effect, that is, surface electron doping and/or redistribution induced by an external electric field.

  11. Optimal reactive power and voltage control in distribution networks with distributed generators by fuzzy adaptive hybrid particle swarm optimisation method

    DEFF Research Database (Denmark)

    Chen, Shuheng; Hu, Weihao; Su, Chi

    2015-01-01

    A new and efficient methodology for optimal reactive power and voltage control of distribution networks with distributed generators based on fuzzy adaptive hybrid PSO (FAHPSO) is proposed. The objective is to minimize comprehensive cost, consisting of power loss and operation cost of transformers...... and capacitors, and subject to constraints such as minimum and maximum reactive power limits of distributed generators, maximum deviation of bus voltages, maximum allowable daily switching operation number (MADSON). Particle swarm optimization (PSO) is used to solve the corresponding mixed integer non......-linear programming problem (MINLP) and the hybrid PSO method (HPSO), consisting of three PSO variants, is presented. In order to mitigate the local convergence problem, fuzzy adaptive inference is used to improve the searching process and the final fuzzy adaptive inference based hybrid PSO is proposed. The proposed...

  12. Surface plasmon polaritons on soft-boundary graphene nanoribbons and their application as voltage controlled plasmonic switches and frequency demultiplexers

    CERN Document Server

    Forati, Ebrahim

    2013-01-01

    A graphene sheet gated with a ridged ground plane, creating a soft-boundary (SB) graphene nanoribbon, is considered. By adjusting the ridge parameters and bias voltage a channel can be created on the graphene which can guide TM surface plasmon polaritons (SPP). Two types of modes are found; fundemental and higher-order modes with no apparent cutoff frequency and with energy distributed over the created channel, and edge modes with energy concen-trated at the soft-boundary edge. Dispersion curves, electric near-field patterns, and current distributions of these modes are determined. Since the location where energy is concentrated in the edge modes can be easily controlled electronically by the bias voltage and frequency, the edge-mode phenomena is used to propose a novel voltage controlled plasmonic switch and a plasmonic frequency demultiplexer.

  13. Simulation models developed for voltage control in a distribution network using energy storage systems for PV penetration

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Bindner, Henrik W.

    2013-01-01

    This paper presents the development of simulation models for DER components in a distribution network, with focus on voltage controllers using energy storage systems for PV penetration. The Vanadium Redox Battery (VRB) system model, used as an energy storage system, was implemented in MATLAB....../Simulink and DIgSILENT PowerFactory, based on the efficiency of different components-such as: cell stacks, electrolytes, pumps and power converters, whilst power losses were also taken into account. The simulation results have been validated against measurements using experimental facility of a distributed power...... system laboratory. To study the variability and the interaction between feeders including VRB, PV system and active units an overvoltage controller has also been developed, implemented and tested successfully....

  14. Coordinated Voltage Control in Distribution Network with the Presence of DGs and Variable Loads Using Pareto and Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    José Raúl Castro

    2016-02-01

    Full Text Available This paper presents an efficient algorithm to solve the multi-objective (MO voltage control problem in distribution networks. The proposed algorithm minimizes the following three objectives: voltage variation on pilot buses, reactive power production ratio deviation, and generator voltage deviation. This work leverages two optimization techniques: fuzzy logic to find the optimum value of the reactive power of the distributed generation (DG and Pareto optimization to find the optimal value of the pilot bus voltage so that this produces lower losses under the constraints that the voltage remains within established limits. Variable loads and DGs are taken into account in this paper. The algorithm is tested on an IEEE 13-node test feeder and the results show the effectiveness of the proposed model.

  15. Decentralized Voltage Control Coordination of On-Load Tap Changer Transformers, Distributed Generation Units and Flexible Loads

    DEFF Research Database (Denmark)

    Romani Dalmau, Aina; Martinez Perez, David; Diaz de Cerio Mendaza, Iker

    2015-01-01

    . Under low penetration levels, several voltage regulation elements have been efficiently employed up to now. However, under large distributed generation levels, the traditional techniques have to be coordinated with new upcoming solutions, such us demand response. In this paper a simple and decentralized......The increase of distributed generation is expected to generate instabilities, such as power imbalances or voltage deviations in the power system. At the distribution level, maintaining the bus voltages within the stipulated limits is one of the major challenges for the distribution system operator...... approach is introduced in order to coordinate the voltage control capability from different assets in medium voltage networks. In this sense, the on-load tap changer strategy of the primary substation and the power factor control of wind turbines and combined heat and power plants are combined...

  16. Clinical and Hemodynamic Correlates and Prognostic Value of VE/VCO2 Slope in Patients With Heart Failure With Preserved Ejection Fraction and Pulmonary Hypertension.

    Science.gov (United States)

    Klaassen, Sebastiaan H C; Liu, Licette C Y; Hummel, Yoran M; Damman, Kevin; van der Meer, Peter; Voors, Adriaan A; Hoendermis, Elke S; van Veldhuisen, Dirk J

    2017-07-20

    Impaired exercise capacity is one of the hallmarks of heart failure with preserved ejection fraction (HFpEF), but the clinical and hemodynamic correlates and prognostic value of exercise testing in patients with HFpEF is unknown. Patients with HFpEF (left ventricular ejection fraction [LVEF] ≥45%) and pulmonary hypertension underwent cardiopulmonary exercise test (CPX) to measure maximal (peak VO2) and submaximal (ventilatory equivalent for carbon dioxide [VE/VCO2] slope) exercise capacity. In addition, right heart catheterization was performed. Patients were grouped in tertiles based on the VE/VCO2 slope. Univariate and multivariate regression analyses were performed. A Cox regression analysis was performed to determine the mortality during follow-up. We studied 88 patients: mean age 73 ± 9 years, 67% female, mean LVEF 58%, median N-terminal pro-B-type natriuretic peptide (NT-proBNP) 840 (interquartile range 411-1938) ng/L. Patients in the highest VE/VCO2 tertile had the most severe HF, as reflected in higher New York Heart Association functional class and higher NT-proBNP plasma levels (all P < .05 for trend), whereas LVEF was similar between the groups. Multivariable regression analysis with backward elimination on invasive hemodynamic measurements showed that VE/VCO2 slope was independently associated with pulmonary vascular resistance (PVR). Cox regression analysis showed that increased VE/VCO2 slope (but not peak VO2) was independently associated with increased mortality. Increased VE/VCO2 slope was associated with more severe disease and higher PVR and was independently associated with increased mortality in patients with HFpEF. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Cardiopulmonary Exercise Testing in Patients with Chronic Heart Failure: Prognostic Comparison from Peak VO2 and VE/VCO2 Slope.

    Science.gov (United States)

    Sarullo, Filippo Maria; Fazio, Giovanni; Brusca, Ignazio; Fasullo, Sergio; Paterna, Salvatore; Licata, Pamela; Novo, Giuseppina; Novo, Salvatore; Di Pasquale, Pietro

    2010-05-26

    Cardiopulmonary exercise testing with ventilatory expired gas analysis (CPET) has proven to be a valuable tool for assessing patients with chronic heart failure (CHF). The maximal oxygen uptake (peak V02) is used in risk stratification of patients with CHF. The minute ventilation-carbon dioxide production relationship (VE/VCO2 slope) has recently demonstrated prognostic significance in patients with CHF. Between January 2006 and December 2007 we performed CPET in 184 pts (146 M, 38 F, mean age 59.8 +/- 12.9 years), with stable CHF (96 coronary artery disease, 88 dilated cardiomyopathy), in NYHA functional class II (n.107) - III (n.77), with left ventricular ejection fraction (LVEF) /= 35.6 and 25% in those with VE/VCO2 slope 12.2 ml/kg/min (log rank chi2: 50.98, p /= 32.5 and 23% in those with VE/VCO2 slope 12.3 ml/kg/min (log rank chi2: 72.86, p < 0.0001). The VE/VCO2 slope was demonstrated with receiver operating characteristic curve analysis to be equivalent to peak VO2 in predicting cardiac-related mortality (0.89 vs. 0.89). Although area under the receiver operating characteristic curve for the VE/VCO2 slope was greater than peak VO2 in predicting cardiac-related hospitalization (0.88 vs 0.82), the difference was no statistically significant (p = 0.13). These results add to the present body of knowledge supporting the use of CPET in CHF patients. The VE/VCO2 slope, as an index of ventilatory response to exercise, is an excellent prognostic parameter and improves the risk stratification of CHF patients. It is easier to obtain than parameters of maximal exercise capacity and is of equivalent prognostic importance than peak VO2.

  18. Automatic tuning of quality factors for VHF CMOS filters

    NARCIS (Netherlands)

    Nauta, Bram; Seevinck, Evert

    1990-01-01

    A VHF transconductance-C filter technique with automatic tuning of the quality factors and the cutoff frequency, based on a voltage controlled oscillator (VCO), is presented. The Q-tuning circuit is very simple and contains no signal carrying nodes, resulting in a well-controlled Q up to very high f

  19. Meixner oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Atakishiyev, N.M. [Instituto de Matematicas. Universidad Nacional Autonoma de Mexico. Cuernavaca, Morelos (Mexico); Jafarov, E.I.; Nagiyev, S.M. [Institute of Physics, Azerbaijan Academy of Sciences. Baku, Azerbaijan (Azerbaijan); Wolf, K.B. [Instituto de Investigaciones en Matematicas Aplicadas y en Sistemas. Universidad Nacional Autonoma de Mexico. Cuernavaca, Morelos (Mexico)

    1998-10-01

    Meixner oscillators have a ground state and an energy spectrum that is equally spaced; they are a two-parameter family of models that satisfy a Hamiltonian equation with a difference operator. Meixner oscillators include as limits and particular cases the Charlier, Kravchuk and Hermite (common quantum-mechanical) harmonic oscillators. By the Sommerfeld-Watson transformation they are also related with a relativistic model of the linear harmonic oscillator, built in terms of the Meixner-Pollaczek polynomials, and their continuous weight function. We construct explicitly the corresponding coherent states with the dynamical symmetry group Sp(2,R). The reproducing kernel for the wavefunctions of these models is also found. (Author)

  20. VCO Design and Simulation Using TSMC 0.18 m Process to Meet IEEE802.11a Requirements

    Directory of Open Access Journals (Sweden)

    AliReza Neshat-Niko

    2008-06-01

    Full Text Available A complimentary topology is used incorporating TSMC 0.18 mm process to design a CMOS VCO with the center frequency of 5.4 GHz. Simulation results showed tuning range of 13%. The phase noise at 1 MHz offset was measured to be -118.7 dBc/Hz. The VCO core power consumption was 3.3 mW when the power supply voltage was set to 1.5 V. Simulation results verified that the designed structure meets the IEEE802.11a requirements.

  1. Design And Investigation Of 65 Nm Rf Cmos Technology Lc-Vco’s

    OpenAIRE

    Vytautas Mačaitis; Vaidotas Barzdėnas

    2014-01-01

    In this paper, two LC Voltage-Controlled Oscillators (LC-LC-VCO1 and LC-VCO2) are designed using TSMC 65 nm LP/MS/RF CMOS technology. Two arrays, one of which is a 6-bit capacitor array and the other – an array of MOS varactors, provide a wide LC-VCO frequency tuning range. Post-layout simulation results unveiled that at 1.8 V supply voltage the tuning range of LC-VCO1 spans from 5.17 GHz to 6.76 GHz and for LC-VCO2 the range spans from 6.33 GHz to 8.08 GHz. The phase noise at 1 MHz offset fr...

  2. 采用0.13 μm RF CMOS工艺的105 GHz VCO

    Institute of Scientific and Technical Information of China (English)

    陈裕权

    2005-01-01

    <正>UMC采用其0.13μm RF CMOS工艺技术制造出一种压控振荡器 (VCO),其基本工作频率达到创记录的105 GHz。该芯片是由佛罗里达大学的电气与计算机工程学院的硅微波集成电路和系统研究组设计开发的。过去最高记录基本工作频率的CMOS电(?)是采用90 nm CMOS工艺制造的103 GHz振荡器,它消耗4倍的功率。而(?)大学的这项最新成果为105 GHz 的VCO和一个调频范围为2.4 GHz的99 GHz VCO,采用的是0.13 μm制程工艺。

  3. Preparation and physicochemical evaluation of emulsified virgin coconut oil (VCO)-carica papaya extract concoction using Tween80

    Science.gov (United States)

    Omar, Hazreen; Zubairi, Saiful Irwan; Fadhilah, Mohd Faizulhelmi; Omar, Dzolkhifli; Asib, Norhayu

    2016-11-01

    Carica papaya is a member of the Caricaceae. Its leaves have been used in folk medicine for centuries. Recent studies have shown its beneficial effects as an anti-inflammatory agent (Owoyele et al 2008) and anti-tumour15 as well as antioxidant and wound healing properties7. The study has shown that the effect of carica papaya leaves juice intake also can accelerate the rate of increase in platelet count among the patients infected with dengue fever and dengue haemorrhagic fever18. With all the goodness of carica papaya leaves, a formulation with addition of virgin coconut oil (VCO) is produced to give an enhanced supplement beverage to market nowadays. Virgin coconut oil is well known as anti-oxidant4. The combination of these two substances gives a balance combination in healthy supplement. In recent years the application of emulsion is rapidly increasing in many fields such as cosmetics and paints. Emulsions are dispersions of droplets of one liquid in another, immiscible, liquid in which the droplets are of colloidal or near-colloidal sizes. The combination of water and oil (VCO) with addition of non-ionic surfactant Tween80 was constructed using ternary phase diagram. By considering the Hydrophilic-Lipophilic Balance (HLB) value of each substance will help in producing a stable emulsion.

  4. 1.3~2.2 GHz低噪声低功耗 CMOS LC VCO的设计%A 1 .3~2 .2 GHz Low Phase-Noise Low-Power CMOS LC VCO

    Institute of Scientific and Technical Information of China (English)

    陈华; 郭桂良; 张玉琳; 姜宇; 韩荆宇; 阎跃鹏

    2015-01-01

    This paper presents a wide‐band low phase‐noise and low power voltage‐controlled oscillator (VCO) .To cover a frequency range of 1 .3~2 .2 GHz and maintain extremely low gain ,a bunch of 128 tuning curves realized by 7‐bit switching capacitor array is applied in VCO .On the other hand ,wide‐range leads to huge gain variation .To combat it ,a 3‐bit self‐controlled varactor array is also proposed .Besides ,to enlarge each tuning curve linear range , distributed biased varactor technique is still adopted .Fabricated in TSMC 0 .18μm CMOS process ,the tuning curve linear range is 0 .2~1 .6 V ,and VCO can cover 1 .3~2 .17 GHz frequency .The overlap of high band adjacent curves is more than 50% ,and low band is even more than 80% .The average gain is only 19 M Hz/V ,and the fluctuation range is 13~25 MHz/V .For 1312 MHz ,the VCO phase noise is‐116 .53dBc/Hz at 1MHz offset ;while for 2 152 M Hz ,it is‐112 .78 dBc/Hz .VCO consumes 1 .2~3 .2 mA for a 1 .8 V supply voltage .The proposed VCO can achieve wide tuning range and low phase noise . It has been successfully integrated in the frequency synthesizer for Wireless networks for Industrial Automation (WIA) applications .%基于TSMC 0.18μm RFCMOS工艺,设计并实现了一个宽带低功耗低相位噪声的高性能压控振荡器(VCO).为实现1.3~2.2 GHz调谐范围,VCO采用7‐bit(128根调谐曲线)固定电容阵列,同时也获得了超低的增益,降低了相位噪声.为弱化宽调谐范围带来的增益波动,VCO采用3‐bit可变电容阵列来提升低带曲线的斜率,以期与高带一致.为实现每根曲线的宽线性范围,可变电容采用分布式偏置电压技术.为降低相位噪声,还提出了一种输出零偏置架构以及电流源噪声滤除技术.测试结果表明,调谐电压的线性范围为0.2~1.6 V ;VCO输出频率范围为1.3~2.17 GHz ;高带调谐曲线叠合超过50%,低带超过80

  5. Power Oscillations Damping in DC Microgrids

    DEFF Research Database (Denmark)

    Hamzeh, Mohsen; Ghafouri, Mohsen; Karimi, Houshang

    2016-01-01

    This paper proposes a new control strategy for damping of power oscillations in a multi-source dc microgrid. A parallel combination of a fuel cell (FC), a photovoltaic (PV) system and a supercapacitor (SC) are used as a hybrid power conversion system (HPCS). The SC compensates for the slow...... transient response of the FC stack. The HPCS controller comprises a multi-loop voltage controller and a virtual impedance loop for power management. The virtual impedance loop uses a dynamic droop gain to actively damp the low-frequency oscillations of the power sharing control unit. The gain of virtual...... impedance loop is determined using small signal analysis and pole placement method. The Mesh analysis is employed to further study the stability of low-frequency modes of the overall dc microgrid. Moreover, based on the guardian map theorem, a robust stability analysis is carried out to determine...

  6. Oscillate Boiling

    CERN Document Server

    Li, Fenfang; Nguyen, Dang Minh; Ohl, Claus-Dieter

    2016-01-01

    We report about an intriguing boiling regime occurring for small heaters embedded on the boundary in subcooled water. The microheater is realized by focusing a continuous wave laser beam to about $10\\,\\mu$m in diameter onto a 165\\,nm-thick layer of gold, which is submerged in water. After an initial vaporous explosion a single bubble oscillates continuously and repeatably at several $100\\,$kHz. The microbubble's oscillations are accompanied with bubble pinch-off leading to a stream of gaseous bubbles into the subcooled water. The self-driven bubble oscillation is explained with a thermally kicked oscillator caused by the non-spherical collapses and by surface pinning. Additionally, Marangoni stresses induce a recirculating streaming flow which transports cold liquid towards the microheater reducing diffusion of heat along the substrate and therefore stabilizing the phenomenon to many million cycles. We speculate that this oscillate boiling regime may allow to overcome the heat transfer thresholds observed dur...

  7. A voltage-controlled silver nanograting device for dynamic modulation of transmitted light based on the surface plasmon polariton effect

    Science.gov (United States)

    Wang, Hailong; Li, Haibo; Wang, Yi; Xu, Shuping; Xu, Weiqing

    2016-02-01

    An active-controlled plasmonic device is designed and fabricated based on the index-sensitive properties of surface plasmon polaritons (SPPs). We utilize a one-dimensional silver nanograting with a period of 320 nm overlayered with a liquid crystal (LC) layer (50 μm in thickness), to transmit selectively the surface plasmon resonance (SPR) wavelength. This device realizes the active, reversible and continuous control of the transmitted light wavelength by modulating the external voltage signal applied to the LC layer. This voltage-controlled plasmonic filter has a dynamic wavelength modulation range of 17 nm, a fast respond speed of 4.24 ms and a low driving voltage of 1.06 V μm-1. This study opens up a unique way for the design of tunable nanophotonic devices, such as a micro light sources and switches.An active-controlled plasmonic device is designed and fabricated based on the index-sensitive properties of surface plasmon polaritons (SPPs). We utilize a one-dimensional silver nanograting with a period of 320 nm overlayered with a liquid crystal (LC) layer (50 μm in thickness), to transmit selectively the surface plasmon resonance (SPR) wavelength. This device realizes the active, reversible and continuous control of the transmitted light wavelength by modulating the external voltage signal applied to the LC layer. This voltage-controlled plasmonic filter has a dynamic wavelength modulation range of 17 nm, a fast respond speed of 4.24 ms and a low driving voltage of 1.06 V μm-1. This study opens up a unique way for the design of tunable nanophotonic devices, such as a micro light sources and switches. Electronic supplementary information (ESI) available: (1) The general theory of the VCP filter; (2) RI sensitivity; (3) the thickness optimization of the Ag grating sandwiched by photoresist layers; (4) image system; (5) detection systems for transmission and reflection spectra; (6) detection system for the response time of the VCP filter. See DOI: 10.1039/c5nr

  8. First-principles calculated spin-gapless semiconducting behavior in quaternary VCoHfGa and CrFeHfGa Heusler compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiude; Wu, Xiaolin [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China); Wu, Bo, E-mail: fqwubo@zync.edu.cn [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China); School of Marine Science and Technology, Northwestern Polytechnical University, Xian 710072 (China); Feng, Yu [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Ping [Institute for Clean Energy & Advanced Materials (ICAEM), Southwest University, Chongqing 400715 (China); Huang, Haishen [Institute of Theoretical Physics, Zunyi Normal College, Zunyi 563002 (China)

    2016-07-15

    Highlights: • Structural, electronic and magnetic properties of quaternary Heusler alloy [VCo,CrFe]HfGa were detected theoretically. • The quaternary Heusler alloy [VCo,CrFe]HfGa are (or are nearly) spin gapless semiconductors at the lowest energy state. • The ferromagnetic coupling plays an important role in magnetism. - Abstract: By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the structural, electronic and magnetic properties of LiMgPdSn-type quaternary Heusler alloy CrFeHfGa and VCoHfGa were detected compressively. The results reveal that the two alloys are (or are nearly) potential spin gapless semiconductors with a magnetic moment of 3 μ{sub B} per primitive cell and the minority-spin gap of 0.8 eV and 0.6 eV at Fermi level (ε{sub F}) during the rate of lattice change of about −5%, respectively. We deduce that the ferromagnetic coupling among transitional metals plays an important role in magnetism of Heusler alloy [CrFe,VCo]HfGa.

  9. An Overview of Linearity Correction Technology for Tuning Characteristics of VCO%VCO电调特性的线性校正技术综述

    Institute of Scientific and Technical Information of China (English)

    冷建伟; 齐晓辉

    2012-01-01

    VCO电调特性的线性校正技术是决定线性调频连续波雷达系统性能的关键技术之一.给出了VCO电调线性度的基本定义.VCO电调特性的线性校正技术主要包括电抗补偿线性校正、开环线性校正和闭环线性校正三种基本校正方案.详细分析了各种校正方案的基本原理,并对各种校正方案的优缺点进行了对比分析;同时,详细介绍了VCO线性校正技术的最新研究进展.%Linearity correction technology for tuning characteristics of VCO is the key to performance of linear frequency modulation continuous wave (LFMCW) radar system. Basic definition of VCO tuning linearity was described. Linearity correction technology for VCO tuning characteristics mainly includes three basic schemes; reactance compensation, open loop and closed loop linearity corrections. Basic principles of each correction schemes were analyzed in detail, and their advantages and disadvantages were discussed. At the same time, the latest development in research on linearity correction technology for VCO tuning characteristics were described in particular.

  10. FORMULASI DAN STABILITAS MIKROEMULSI O/W DENGAN METODE EMULSIFIKASI SPONTAN MENGGUNAKAN VCO DAN MINYAK SAWIT SEBAGAI FASE MINYAK: PENGARUH RASIO SURFAKTAN-MINYAK

    Directory of Open Access Journals (Sweden)

    Setyaningrum Ariviani

    2015-05-01

    Mikroemulsi tersebut memiliki distribusi ukuran partikel monomodal, rerata diameter partikel dan viskositas mencapai 21,7 ± 0,02nm dan 6,0 ± 0,10cp (VCO, 22,9 ± 0,15nm dan 6,2 ± 0,05cp (minyak sawit. Kata kunci: Mikroemulsi, formulasi, stabilitas, surfaktan minyak

  11. Ultra Low Energy Switching of Ferromagnet with Perpendicular Anisotropy on Topological Insulator by Voltage Controlled Magnetic Anisotropy

    Science.gov (United States)

    Ghosh, Bahniman; Pramanik, Tanmoy; Dey, Rik; Roy, Urmimala; Register, Leonard; Banerjee, Sanjay

    2015-03-01

    We propose and demonstrate, through simulation, an ultra low energy memory device on a topological insulator thin film. The device consists of a thin layer of Fe deposited on the surface of a topological insulator, Bi2Se3. The top surface of Fe is covered with MgO so that the ferromagnetic layer has perpendicular anisotropy. Current is passed on the surface of the topological insulator which switches the magnetization of the Fe ferromagnet through strong exchange interaction, between electrons contributing to the surface current on the Bi2Se3 and the d electrons in the ferromagnet, and spin transfer torque due to shunting of current through the ferromagnet. Voltage controlled magnetic anisotropy enables ultra low energy switching. Our micromagnetic simulations, predict switching time of the order of 2.4 ns and switching energy of the order of 0.16 fJ for a ferromagnetic bit with thermal stability of 90 kBT. The proposed structure combines the advantages of both large spin torque from topological insulators and those of perpendicular anisotropy materials. This work is supported by NRI SWAN and NSF NASCENT Center.

  12. Simultaneous Kerr and Faraday investigations of boundary magnetization and order parameter switching in voltage-controllable exchange bias films

    Science.gov (United States)

    Wang, Junlei; Echtenkamp, Will; Street, Mike; Binek, Christian

    2015-03-01

    Magnetoelectric oxides are of great interest for ultra-low power spintronics with memory and logic function. A key property for the realization of electrically switchable state variables is the voltage-controlled boundary magnetization in magnetoelectric antiferromagnets. It allows electric switching of an adjacent exchange coupled ferromagnetic layer in the absence of dissipative currents. Previous surface sensitive measurements of boundary magnetization in thin films of the archetypical magnetoelectric antiferromagnet chromia lacked explicit demonstration of the predicted rigid coupling between the bulk antiferromagnetic order parameter and the boundary magnetization. We designed a magneto-optical setup allowing simultaneous measurement of Kerr and Faraday rotation. Our experiments correlate electric field induced bulk magneto-optical effects (non-reciprocal rotation), including the response on switching of the antiferromagnetic order parameter, with the boundary magnetization. Our results suggest that switching of a ferromagnetic film strongly exchange coupled to a magnetoelectric antiferromagnetic ultra-thin film allows switching of the antiferromagnetic order parameter. We investigate the possibility that this switching phenomenon might induce a voltage pulse via a generalized variation of the inverse linear magnetoelectric effect. This project was supported by SRC through CNFD, an SRC-NRI Center, by C-SPIN, part of STARnet, and by the NSF through MRSEC.

  13. Harmonics Phase Shifter for a Three-Phase System with Voltage Control by Integral-Cycle Triggering Mode of Thyristors

    Directory of Open Access Journals (Sweden)

    I. Badran

    2008-01-01

    Full Text Available n integral-cycle triggering mode of voltage control, subharmonic as well as higher order harmonic components are generated in the load voltage waveforms of a three-phase system. These harmonic components are found to be unbalanced in phase displacement. The correction of the unbalanced phase displacement angles of a particular subharmonic or higher order harmonic for this type of triggering is investigated to solve the limitation of use of this important type of control as a drive and many other industrial applications. In this research a new phase shifting technique is proposed to correct the unbalanced phase displacement angles in the three-phase system. This technique depends on shifting the waveforms of either phase B or phase C or both by multiples of 2π. A microprocessor-based harmonic phase shifter is designed and tested with three-phase resistive and induction motor loads. It is found that there is a well agreement between the theoretical and experimental results and it is believed that the major problem of harmonics phase unbalances associated with the integral-cycle triggering mode of thyristors when used with three-phase circuits have been solved in the present research.

  14. Thermally stable voltage-controlled perpendicular magnetic anisotropy in Mo|CoFeB|MgO structures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang, E-mail: xiang.li@ucla.edu; Yu, Guoqiang; Wong, Kin; Upadhyaya, Pramey; Akyol, Mustafa; Wang, Kang L., E-mail: wang@seas.ucla.edu [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Wu, Hao; Han, Xiufeng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Ong, P. V.; Kioussis, Nicholas [Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330 (United States); Hu, Qi; Ebrahimi, Farbod [Inston Inc., Los Angeles, California 90095 (United States); Khalili Amiri, Pedram, E-mail: pedramk@ucla.edu [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Inston Inc., Los Angeles, California 90095 (United States)

    2015-10-05

    We study voltage-controlled magnetic anisotropy (VCMA) and other magnetic properties in annealed Mo|CoFeB|MgO layered structures. The interfacial perpendicular magnetic anisotropy (PMA) is observed to increase with annealing over the studied temperature range, and a VCMA coefficient of about 40 fJ/V-m is sustained after annealing at temperatures as high as 430 °C. Ab initio electronic structure calculations of interfacial PMA as a function of strain further show that strain relaxation may lead to the increase of interfacial PMA at higher annealing temperatures. Measurements also show that there is no significant VCMA and interfacial PMA dependence on the CoFeB thickness over the studied range, which illustrates the interfacial origin of the anisotropy and its voltage dependence, i.e., the VCMA effect. The high thermal annealing stability of Mo|CoFeB|MgO structures makes them compatible with advanced CMOS back-end-of-line processes, and will be important for integration of magnetoelectric random access memory into on-chip embedded applications.

  15. Improvement of the voltage-controlled negative resistance of a porous silicon emitter using cathode reduction and electro-pretreatment

    Science.gov (United States)

    He, Li; Zhang, Xiaoning; Wang, Wenjiang; Zhao, Xiaoning

    2016-09-01

    A new composite treatment method combining cathode reduction (CR) and electro-pretreatment (EP) is proposed to improve the voltage-controlled negative resistance (VCNR) of porous silicon (PS) emitters. Four groups of PS emitters were treated, with nothing, CR, EP, and a combination of CR and EP, during different preparation stages. The experimental results indicate that both CR and EP improved the VCNR property and the emission characteristics of the PS emitter. The most favorable results occurred for the electron emitter treated with a combination of CR-EP. A peak-to-valley current ratio of 1.06 and an emission current density of 150 µA cm-2, which are the lowest value and approximately twice that of other samples, respectively, were obtained. In addition, the operating stability of the PS emitter also improved significantly compared with the two methods alone. Scanning electron microscopy, atomic force microscopy, and energy dispersive x-ray spectrometry results demonstrate that the improvements of the VCNR and the emission characteristics of PS emitters are due to the content variation of defects, impurities, and unstable microstructures in the PS layer under the influence of CR and EP. The mechanism of VCNR behavior is explained by a proposed energy band model, which is consistent with the experimental results.

  16. Biased low differential input impedance current receiver/converter device and method for low noise readout from voltage-controlled detectors

    Science.gov (United States)

    Degtiarenko, Pavel V.; Popov, Vladimir E.

    2011-03-22

    A first stage electronic system for receiving charge or current from voltage-controlled sensors or detectors that includes a low input impedance current receiver/converter device (for example, a transimpedance amplifier), which is directly coupled to the sensor output, a source of bias voltage, and the device's power supply (or supplies), which use the biased voltage point as a baseline.

  17. PLL jitter reduction by utilizing a ferroelectric capacitor as a VCO timing element.

    Science.gov (United States)

    Pauls, Greg; Kalkur, Thottam S

    2007-06-01

    Ferroelectric capacitors have steadily been integrated into semiconductor processes due to their potential as storage elements within memory devices. Polarization reversal within ferroelectric capacitors creates a high nonlinear dielectric constant along with a hysteresis profile. Due to these attributes, a phase-locked loop (PLL), when based on a ferroelectric capacitor, has the advantage of reduced cycle-to-cycle jitter. PLLs based on ferroelectric capacitors represent a new research area for reduction of oscillator jitter.

  18. The effects of virgin coconut oil (VCO) as supplementation on quality of life (QOL) among breast cancer patients.

    Science.gov (United States)

    Law, Kim Sooi; Azman, Nizuwan; Omar, Eshaifol Azam; Musa, Muhammad Yusri; Yusoff, Narazah Mohd; Sulaiman, Siti Amrah; Hussain, Nik Hazlina Nik

    2014-08-27

    Breast cancer is the most common cancer amongst Malaysian women. Both the disease and its treatment can disrupt the lives of the woman and adversely affect all aspects of life and thus can alter a woman's quality of life. The aim of this study was to examine the effect of virgin coconut oil (VCO) on the quality of life (QOL) of patients diagnosed with breast cancer. This was a prospective study of breast cancer patients admitted into the Oncology Unit of Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia. The sample consisted of 60 patients with stage III and IV breast cancer allocated to either an intervention group (n = 30) or a control group (n = 30) using a simple random table. QOL was evaluated from the first cycle of chemotherapy to the sixth cycle, and data were collected using a validated Bahasa Malaysia version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module (EORTC QLQ-C30) and its breast-specific module (QLQ-BR 23). The mean age of breast cancer patients was 50.2 (SD = 13.5) years. There were significant mean score differences for functioning and global QOL between groups (α < 0.01). The intervention group also had better scores for symptoms including fatigue, dyspnea, sleep difficulties, and loss of appetite compared to the control group. Although there are deteriorations for sexual enjoyment, the intervention group exhibited improvement in breast functioning and symptom scores for body image, sexual function, future perspective, breast symptoms, and systemic therapy side effects. VCO consumption during chemotherapy helped improve the functional status and global QOL of breast cancer patients. In addition, it reduced the symptoms related to side effects of chemotherapy.

  19. Oscillation death in coupled oscillators

    Institute of Scientific and Technical Information of China (English)

    Wei ZOU; Xin-gang WANG; Qi ZHAO; Meng ZHAN

    2009-01-01

    We study dynamical behaviors in coupled nonlinear oscillators and find that under certain condi- tions, a whole coupled oscillator system can cease oscil- lation and transfer to a globally nonuniform stationary state [I.e., the so-called oscillation death (OD) state], and this phenomenon can be generally observed. This OD state depends on coupling strengths and is clearly differ- ent from previously studied amplitude death (AD) state, which refers to the phenomenon where the whole system is trapped into homogeneously steady state of a fixed point, which already exists but is unstable in the ab- sence of coupling. For larger systems, very rich pattern structures of global death states are observed. These Turing-like patterns may share some essential features with the classical Turing pattern.

  20. Cathodic voltage-controlled electrical stimulation of titanium implants as treatment for methicillin-resistant Staphylococcus aureus periprosthetic infections.

    Science.gov (United States)

    Ehrensberger, Mark T; Tobias, Menachem E; Nodzo, Scott R; Hansen, Lisa A; Luke-Marshall, Nicole R; Cole, Ross F; Wild, Linda M; Campagnari, Anthony A

    2015-02-01

    Effective treatment options are often limited for implant-associated orthopedic infections. In this study we evaluated the antimicrobial effects of applying cathodic voltage-controlled electrical stimulation (CVCES) of -1.8 V (vs. Ag/AgCl) to commercially pure titanium (cpTi) substrates with preformed biofilm-like structures of methicillin-resistant Staphylococcus aureus (MRSA). The in vitro studies showed that as compared to the open circuit potential (OCP) conditions, CVCES of -1.8 V for 1 h significantly reduced the colony-forming units (CFU) of MRSA enumerated from the cpTi by 97% (1.89 × 106 vs 6.45 × 104 CFU/ml) and from the surrounding solution by 92% (6.63 × 105 vs. 5.15 × 104 CFU/ml). The in vivo studies, utilizing a rodent periprosthetic infection model, showed that as compared to the OCP conditions, CVCES at -1.8 V for 1 h significantly reduced MRSA CFUs in the bone tissue by 87% (1.15 × 105 vs. 1.48 × 104 CFU/ml) and reduced CFU on the cpTi implant by 98% (5.48 × 104 vs 1.16 × 103 CFU/ml). The stimulation was not associated with histological changes in the host tissue surrounding the implant. As compared to the OCP conditions, the -1.8 V stimulation significantly increased the interfacial capacitance (18.93 vs. 98.25 μF/cm(2)) and decreased polarization resistance (868,250 vs. 108 Ω-cm(2)) of the cpTi. The antimicrobial effects are thought to be associated with these voltage-dependent electrochemical surface properties of the cpTi.

  1. Neutrino Oscillations

    Directory of Open Access Journals (Sweden)

    G. Bellini

    2014-01-01

    Full Text Available In the last decades, a very important breakthrough has been brought about in the elementary particle physics by the discovery of the phenomenon of the neutrino oscillations, which has shown neutrino properties beyond the Standard Model. But a full understanding of the various aspects of the neutrino oscillations is far to be achieved. In this paper the theoretical background of the neutrino oscillation phenomenon is described, referring in particular to the paradigmatic models. Then the various techniques and detectors which studied neutrinos from different sources are discussed, starting from the pioneering ones up to the detectors still in operation and to those in preparation. The physics results are finally presented adopting the same research path which has been crossed by this long saga. The problems not yet fixed in this field are discussed, together with the perspectives of their solutions in the near future.

  2. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  3. Antiperiodic oscillations

    Science.gov (United States)

    Freire, Joana G.; Cabeza, Cecilia; Marti, Arturo; Pöschel, Thorsten; Gallas, Jason A. C.

    2013-06-01

    The investigation of regular and irregular patterns in nonlinear oscillators is an outstanding problem in physics and in all natural sciences. In general, regularity is understood as tantamount to periodicity. However, there is now a flurry of works proving the existence of ``antiperiodicity'', an unfamiliar type of regularity. Here we report the experimental observation and numerical corroboration of antiperiodic oscillations. In contrast to the isolated solutions presently known, we report infinite hierarchies of antiperiodic waveforms that can be tuned continuously and that form wide spiral-shaped stability phases in the control parameter plane. The waveform complexity increases towards the focal point common to all spirals, a key hub interconnecting them all.

  4. Six-step Voltage Control of PM Brushless AC Motors under High Speed Flux-weakening Operation for EV/HEV Applications

    Institute of Scientific and Technical Information of China (English)

    诸自强

    2008-01-01

    The torque-speed characteristics of brushless motor having an interior permanent magnet rotor and a sinusoidalback-emf waveform are compared experimentally when it is operated in brushless AC (BLAC) mode and brushless DC(BLDC) modes with both 2-phase, 120° conduction (BLDC-120) and 3-phase,180° conduction (BLDC-180).Particularemphasis is on high-speed,six-step voltage controlled,flux-weakening operation.h is shown that for EV/HEV applications,even for interior PM brushless motors which have sinusoidal back-emf waveforms,in order to achieve maximum torque perampere capability over wide operation speed range,it is advantageous to employ a hybrid operation mode-BLAC operationin the constant torque region and six-step voltage control (BLDC-180 operation, together with current phase control) inthe flux-weakening region.

  5. 湖南电网电压协调控制方案%Coordinated Scheme for Automatic Voltage Control of Hunan Power Grid

    Institute of Scientific and Technical Information of China (English)

    于汀; 王伟

    2011-01-01

    In order to optimize voltage regulation ability of Hunan Power Grid, a voltage and reactive power optimal control model, in which the least network loss is taken as objective, and a voltage correction control model independent of the state estimation results are built. Taking Hunan power grid for example, a coordinated scheme for voltage control in which the reactive power at high voltage side is taken as coordinative variable is proposed. The (automatic voltage control) AVC system in provincial dispatching center transmits the reactive power regulation range at the gateway and the command of reactive power compensation direction to the AVC system of regional dispatching department. The coordinated voltage control results in Hunan power grid show that the proposed scheme can effectively reduce network loss and decrease the off-limit probability of voltage.%为优化湖南电网电压调节能力,建立了以网损最小为目标的电压无功优化控制模型,并建立了不依赖于状态估计结果的电压校正控制模型.以湖南电网为例,提出了以关口变电站高压侧无功为协调变量的电压协调控制方案,省调自动电压控制(automatic voltage control,AVC)系统向地调AVC系统下发关口无功调节范围和无功补偿方向指令.湖南省电压协调控制结果表明,该方案可有效降低系统网损,减少电压越限概率.

  6. A 9.8-mW 1.2-GHz CMOS frequency synthesizer with a low phase-noise LC-VCO and an I/Q frequency divider

    Energy Technology Data Exchange (ETDEWEB)

    Li Zhenrong; Zhuang Yiqi; Li Bing; Jin Gang, E-mail: allen_lzr@126.com [Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2011-07-15

    A 1.2 GHz frequency synthesizer integrated in a RF receiver for Beidou navigation is implemented in standard 0.18 {mu}m CMOS technology. A distributed biased varactor LC voltage-controlled oscillator is employed to achieve low tuning sensitivity and optimized phase noise performance. A high-speed and low-switching-noise divider-by-2 circuit based on a source-coupled logic structure is adopted to generate a quadrature (I/Q) local oscillating signal. A high-speed 8/9 dual-modulus prescaler (DMP), a programmable-delay phase frequency detector without dead-zone problem, and a programmable-current charge pump are also integrated into the frequency synthesizer. The frequency synthesizer demonstrates an output frequency from 1.05 to 1.30 GHz, and the phase noise is -98.53 dBc/Hz at 100-kHz offset and -121.92 dBc/Hz at 1-MHz offset from the carrier frequency of 1.21 GHz. The power dissipation of the core circuits without the output buffer is 9.8 mW from a 1.8 V power supply. The total area of the receiver is 2.4 x 1.6 mm{sup 2}. (semiconductor integrated circuits)

  7. A 5.4mW GPS CMOS quadrature front-end based on a single-stage LNA-mixer-VCO

    DEFF Research Database (Denmark)

    Liscidini, Amtonio; Mazzanti, Andrea; Tonietto, Riccardo

    2006-01-01

    A GPS RF front-end combines the LNA, mixer, and VCO in a single stage and can operate from a 1.2V supply. The chip is implemented in a 0.13um CMOS process and occupies 1.5mm2 active area. It consumes 5.4mW with a 4.8dB NF, 36dB gain, and a P1dB of -31dBm.......A GPS RF front-end combines the LNA, mixer, and VCO in a single stage and can operate from a 1.2V supply. The chip is implemented in a 0.13um CMOS process and occupies 1.5mm2 active area. It consumes 5.4mW with a 4.8dB NF, 36dB gain, and a P1dB of -31dBm....

  8. Design of high-throughput and low-power true random number generator utilizing perpendicularly magnetized voltage-controlled magnetic tunnel junction

    Directory of Open Access Journals (Sweden)

    Hochul Lee

    2017-05-01

    Full Text Available A true random number generator based on perpendicularly magnetized voltage-controlled magnetic tunnel junction devices (MRNG is presented. Unlike MTJs used in memory applications where a stable bit is needed to store information, in this work, the MTJ is intentionally designed with small perpendicular magnetic anisotropy (PMA. This allows one to take advantage of the thermally activated fluctuations of its free layer as a stochastic noise source. Furthermore, we take advantage of the voltage dependence of anisotropy to temporarily change the MTJ state into an unstable state when a voltage is applied. Since the MTJ has two energetically stable states, the final state is randomly chosen by thermal fluctuation. The voltage controlled magnetic anisotropy (VCMA effect is used to generate the metastable state of the MTJ by lowering its energy barrier. The proposed MRNG achieves a high throughput (32 Gbps by implementing a 64×64 MTJ array into CMOS circuits and executing operations in a parallel manner. Furthermore, the circuit consumes very low energy to generate a random bit (31.5 fJ/bit due to the high energy efficiency of the voltage-controlled MTJ switching.

  9. Design of high-throughput and low-power true random number generator utilizing perpendicularly magnetized voltage-controlled magnetic tunnel junction

    Science.gov (United States)

    Lee, Hochul; Ebrahimi, Farbod; Amiri, Pedram Khalili; Wang, Kang L.

    2017-05-01

    A true random number generator based on perpendicularly magnetized voltage-controlled magnetic tunnel junction devices (MRNG) is presented. Unlike MTJs used in memory applications where a stable bit is needed to store information, in this work, the MTJ is intentionally designed with small perpendicular magnetic anisotropy (PMA). This allows one to take advantage of the thermally activated fluctuations of its free layer as a stochastic noise source. Furthermore, we take advantage of the voltage dependence of anisotropy to temporarily change the MTJ state into an unstable state when a voltage is applied. Since the MTJ has two energetically stable states, the final state is randomly chosen by thermal fluctuation. The voltage controlled magnetic anisotropy (VCMA) effect is used to generate the metastable state of the MTJ by lowering its energy barrier. The proposed MRNG achieves a high throughput (32 Gbps) by implementing a 64 ×64 MTJ array into CMOS circuits and executing operations in a parallel manner. Furthermore, the circuit consumes very low energy to generate a random bit (31.5 fJ/bit) due to the high energy efficiency of the voltage-controlled MTJ switching.

  10. SEMICONDUCTOR INTEGRATED CIRCUITS 8.64-11.62 GHz CMOS VCO and divider in a zero-IF 802.11a/b/g WLAN and Bluetooth application

    Science.gov (United States)

    Yu, Sun; Niansong, Mei; Bo, Lu; Yumei, Huang; Zhiliang, Hong

    2010-10-01

    A fully integrated VCO and divider implemented in SMIC 0.13-μm RFCMOS 1P8M technology with a 1.2 V supply voltage is presented. The frequency of the VCO is tuning from 8.64 to 11.62 GHz while the quadrature LO signals for 802.11a WLAN in 5.8 GHz band or for 802.11b/g WLAN and Bluetooth in 2.4 GHz band can be obtained by a frequency division by 2 or 4, respectively. A 6 bit switched capacitor array is applied for precise tuning of all necessary frequency bands. The testing results show that the VCO has a phase noise of—113 dBc @ 1 MHz offset from the carrier of 5.5 GHz by dividing VCO output by two and the VCO core consumes 3.72 mW. The figure-of-merit for the tuning-range (FOMT) of the VCO is -192.6 dBc/Hz.

  11. Design of electro-optic transform transmitter based on VCO%一种基于VCO的电-光转换发射电路的设计

    Institute of Scientific and Technical Information of China (English)

    方志; 赵中原; 邱毓昌

    2001-01-01

    介绍了基于电压控制振荡器(VCO)的电-光转换电路的基本原理,设计了一种基于VCO的电-光转换发射电路,并给出了其响应特性.实验结果表明这种电-光转换发射电路具有良好的实用性.

  12. A study on monitoring of frying performance and oxidative stability of virgin coconut oil (VCO) during continuous/prolonged deep fat frying process using chemical and FTIR spectroscopy.

    Science.gov (United States)

    Srivastava, Yashi; Semwal, Anil Dutt

    2015-02-01

    The performance or quality of the Virgin coconut oil (VCO) during continuous/prolonged deep fat frying of soaked bengal gram dhal was evaluated at 180 °C ± 5 °C for 8 h with the help of physico-chemical and rheological parameters. Chemical changes indicated that the free fatty acid (FFA) content and TBA increased significantly (p ≤ 0.05) from 0.11 to 0.98 % lauric acid and 0.06 to 0.61 malonaldehyde/kg of oil respectively. Initially, the peroxide value (PV) of VCO sample was 3.25 meqO2/kg which increased to 9.12 meqO2/kg after 6 h of frying but at the end of frying the value of PV was again found to decrease (8.01 meqO2/kg). The regression coefficients (R(2)) between CD232, CT270 and frying time were 0.964 and 0.983 respectively. The L*, a* and b* colour values measured on the CIELAB colour scale showed a decrease in L* and increase in a*, b* values after 8 h of continuous frying. The p-AV and total polar compounds were increased significantly (p ≤ 0.05) from 2.41 to 17.93 and 2.77 to 8.14 % respectively. Initially, the viscosity of VCO was 49.87cp which increased to 69.87cp after 8 h of continuous frying. The FTIR spectra justify that VCO samples after 8 h of frying found to be stable and acceptable as there was no change occurred at 1,739 cm(-1) frequency which mainly corresponded to carbonylic compounds resulted from the hydroperoxide decompositions after 8 h of continuous frying.

  13. Effect of VCO to leucocyte differential count, glucose levels and blood creatinine of hyperglycemic and ovalbumin sensitized Mus musculus Balb/c

    Directory of Open Access Journals (Sweden)

    RUBEN DHARMAWAN

    2009-03-01

    Full Text Available Abstract. Handajani NS, Dharmawan R. 2009. Effect of VCO to leucocyte differential count, glucose levels and blood creatinine of hyperglycemic and ovalbumin sensitized Mus musculus Balb/c. Nusantara Bioscience 1: 1-8. Chemical medicines and insulin can decrease glucose blood level on hyperglycemic patients with macro vascular side effect. Diabetes and allergy incidences are influenced by quality and quantity of leucocytes. Lauric acid within VCO reports decreased glucose blood level of diabetes and some allergy incidents. The purpose of the study is to know the effect of VCO on glucose blood level, differential leucocytes count and creatinine blood level on hyperglycemic and normoglicemic ovalbumin sensitized mice. Forty five (45 male (mice of Mus musculus Balb/c with average weight of 35 g are divided into 9 groups with 5 repetitions, those are 4 non alloxan groups and 5 alloxan induced hyperglycemic groups. On 22nd day to 36th day they are sensitize to ovalbumin as allergen. Blood sample was obtained by orbital vena using heparin as anti coagulant in order measuring glucose blood level by GOD method to 6 times, on 1st, 4th, 18th, 22nd, 32nd and 37th days, then are tested by ANOVA followed by DMRT 0.05. On 37th day, differential leucocytes are determined, blood level are counted, and then compared to normal value. The result of this study were that within differential leucocytes count of hyperglycemic mice, neutrophile percentage were much lower than the normal value (3.22%, and lymphocyte percentage were much higher than the normal value (94.54%. Consumed 0.003 mL/35 g VCO more 18 days decreased glucose blood level on hyperglycemic mice, decreased basophile percentage of ovalbumin sensitized mice, normalized neutrophile percentage no increased creatinine blood level.

  14. A low-noise X-band microstrip VCO with 2.5 GHz tuning range using a GaN-on-SiC p-HEMT

    NARCIS (Netherlands)

    Maas, A.M.P.; Vliet, F.E. van

    2005-01-01

    A low-noise X-band microstrip hybrid VCO has been designed and realised using a 2 × 50 μm GaN-on-SiC pseudo-morphic HEMT as the active device. The transistor has been manufactured by TIGER and features a gate-length of 0.15 μm, an fT of 22 GHz, a break-down voltage of 42 Volts and an Idss, close to

  15. Design and Implementation of a High-Voltage Generator with Output Voltage Control for Vehicle ER Shock-Absorber Applications

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A self-oscillating high-voltage generator is proposed to supply voltage for a suspension system in order to control the damping force of an electrorheological (ER fluid shock absorber. By controlling the output voltage level of the generator, the damping force in the ER fluid shock absorber can be adjusted immediately. The shock absorber is part of the suspension system. The high-voltage generator drives a power transistor based on self-excited oscillation, which converts dc to ac. A high-frequency transformer with high turns ratio is used to increase the voltage. In addition, the system uses the car battery as dc power supply. By regulating the duty cycle of the main switch in the buck converter, the output voltage of the buck converter can be linearly adjusted so as to obtain a specific high voltage for ER. The driving system is self-excited; that is, no additional external driving circuit is required. Thus, it reduces cost and simplifies system structure. A prototype version of the actual product is studied to measure and evaluate the key waveforms. The feasibility of the proposed system is verified based on experimental results.

  16. Design and realization of a low jitter ratio 1 GHz ring VCO%一个低抖动比1GHz环形VCO的设计与实现

    Institute of Scientific and Technical Information of China (English)

    田颖; 徐江涛

    2012-01-01

    通过对Weigandt模型进行噪声分析,采用一种改进的差分延迟单元结构,成功设计了一个稳定输出1 GHz的环形压控振荡器.同时,采用SMIC 0.18 μm标准CMOS工艺流片,在输出端增加钳位管和正反馈管使输出电位能够快速转变为给定值,已达到高速振荡频率和较低噪声比的效果.流片后测试结果表明,当控制电压为30μV~ 800 mV时,输出频率可达740 MHz~1.3 GHz,并与输入电压之间呈现良好的线性性;在中心振荡频率为1 GHz时,噪声电压与信号电压的比满足设计要求.%Based on the noise analysis of Weigandt model, an improved differential structure of delay cell is adopted to realize a 1 GHz ring VCO in SMIC 0.18 μm standard CMOS process. The clamping diode and positive feedback transistors are added at the output, so the output voltage transits faster to fixed swing. Therefore, the high speed oscillating frequency is achieved while low jitter ratio is guaranteed. The testing result after tape-out shows when control voltage ranges from 30 μ V to 800 mV, the output frequency shows good linearity with range from 740 MHz to 1.3 GHz, while the jitter voltage to signal voltage at central 1 GHz is acceptable for the application.

  17. VO2 pico e inclinação VE/VCO2 na era dos betabloqueadores na insuficiência cardíaca: uma experiência brasileira Peak VO2 and VE/VCO2 slope in betablockers era in patients with heart failure: a brazilian experience

    Directory of Open Access Journals (Sweden)

    Guilherme Veiga Guimarães

    2008-07-01

    Full Text Available FUNDAMENTO: Estudos têm demonstrado que o consumo de oxigênio de pico (VO2 pico e a inclinação VE/VCO2 são preditores de sobrevida em pacientes com insuficiência cardíaca (IC. Entretanto, com a adição do betabloqueador no tratamento da IC, os valores de prognóstico do VO2 pico e da Inclinação VE/VCO2 não estão totalmente estabelecidos. OBJETIVO: Avaliar o efeito dos betabloqueadores no valor de prognóstico do VO2 pico e da inclinação VE/VCO2 em pacientes com IC. MÉTODOS: Estudamos 391 pacientes com insuficiência cardíaca, com idade de 49 ± 14 anos e fração de ejeção do ventrículo esquerdo de 38 ± 10%. Total de pacientes que usavam (grupo I - GI e não usavam (grupo II - GII betabloqueadores: 229 e 162, respectivamente. Todos os pacientes foram submetidos a teste de esforço cardiopulmonar, em esteira, usando o protocolo de Naughton. RESULTADOS: O VO2 pico 16 ml.kg-1.min-1 categorizaram pacientes com melhor prognóstico em médio prazo. A faixa do VO2 pico entre > 10 e BACKGROUND: Studies have demonstrated that peak oxygen consumption (peak VO2 and the VE/VCO2 slope are predictors of survival in patients with heart failure (HF. However, with the advent of betablockers in the treatment of HF, the prognostic values of peak VO2 and VE/VCO2 slope have not been fully established. OBJECTIVE: To evaluate the effect of betablocker use on the prognostic value of peak VO2 and VE/VCO2 slope in patients with HF. METHODS: We studied 391 patients with heart failure, aged 49 ± 14 years and presenting a left ventricular ejection fraction of 38 ± 10%. The total number of patients that used (Group I - GI or did not use (Group II - GII betablockers was 229 and 162, respectively. All patients were submitted to a cardiopulmonary stress test on a treadmill, using the Naughton protocol. RESULTS: A peak VO2 16 ml.kg-1.min-1 categorizes patients with a better mid-term prognosis. Peak VO2 values between > 10 and < 16 ml.kg-1.min-1 indicated

  18. AC Voltage Control of DC/DC Converters Based on Modular Multilevel Converters in Multi-Terminal High-Voltage Direct Current Transmission Systems

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-12-01

    Full Text Available The AC voltage control of a DC/DC converter based on the modular multilevel converter (MMC is considered under normal operation and during a local DC fault. By actively setting the AC voltage according to the two DC voltages of the DC/DC converter, the modulation index can be near unity, and the DC voltage is effectively utilized to output higher AC voltage. This significantly decreases submodule (SM capacitance and conduction losses of the DC/DC converter, yielding reduced capital cost, volume, and higher efficiency. Additionally, the AC voltage is limited in the controllable range of both the MMCs in the DC/DC converter; thus, over-modulation and uncontrolled currents are actively avoided. The AC voltage control of the DC/DC converter during local DC faults, i.e., standby operation, is also proposed, where only the MMC connected on the faulty cable is blocked, while the other MMC remains operational with zero AC voltage output. Thus, the capacitor voltages can be regulated at the rated value and the decrease of the SM capacitor voltages after the blocking of the DC/DC converter is avoided. Moreover, the fault can still be isolated as quickly as the conventional approach, where both MMCs are blocked and the DC/DC converter is not exposed to the risk of overcurrent. The proposed AC voltage control strategy is assessed in a three-terminal high-voltage direct current (HVDC system incorporating a DC/DC converter, and the simulation results confirm its feasibility.

  19. DC-link Voltage Control to Compensate Voltage Deviation for PV–BESSs Integrated System in Low-Voltage (LV Networks

    Directory of Open Access Journals (Sweden)

    Lee Gyu-sub

    2016-01-01

    Full Text Available The exhaustion of fossil fuel and the greenhouse gas emission are one of the most significant energy and environmental issues, respectively. Photovoltaic (PV generators and battery energy storage systems (BESSs have been significantly increased for recent years. The BESSs are mainly used for smoothing active power fluctuation of the PV. In this paper, PV–BESSs integration of two DC/DC converters and one AC/DC converter is investigated and DC-link voltage control to compensate the AC voltage deviation is proposed for the PV‒BESS system in low-voltage (LV networks.

  20. Coordinated voltage control of a decoupled three-phase on load tap changer transformer and photovoltaic inverters for managing unbalanced networks

    DEFF Research Database (Denmark)

    Hu, Junjie; Marinelli, Mattia; Coppo, Massimiliano;

    2016-01-01

    phases. To address this problem, distribution transformers with single-phase tapping capability, together with reactive power provision of PV systems, are under investigation. This paper presents modeling and analysis of the benefits of coordinated voltage control of a decoupled three-phase on-load tap...... profiles on a real Danish distribution grid, as well as the developed dynamic photovoltaic generation and load models. The simulations show that the joint action of the power distribution transformer with OLTC control on each phase, and the reactive power provision of photovoltaic inverters, significantly...

  1. Power oscillation damping controller

    DEFF Research Database (Denmark)

    2012-01-01

    A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...

  2. Grid oscillators

    Science.gov (United States)

    Popovic, Zorana B.; Kim, Moonil; Rutledge, David B.

    1988-01-01

    Loading a two-dimensional grid with active devices offers a means of combining the power of solid-state oscillators in the microwave and millimeter-wave range. The grid structure allows a large number of negative resistance devices to be combined. This approach is attractive because the active devices do not require an external locking signal, and the combining is done in free space. In addition, the loaded grid is a planar structure amenable to monolithic integration. Measurements on a 25-MESFET grid at 9.7 GHz show power-combining and frequency-locking without an external locking signal, with an ERP of 37 W. Experimental far-field patterns agree with theoretical results obtained using reciprocity.

  3. Oscillators and Eigenvalues

    DEFF Research Database (Denmark)

    Lindberg, Erik

    1997-01-01

    In order to obtain insight in the nature of nonlinear oscillators the eigenvalues of the linearized Jacobian of the differential equations describing the oscillator are found and displayed as functions of time. A number of oscillators are studied including Dewey's oscillator (piecewise linear...... with negative resistance), Kennedy's Colpitts-oscillator (with and without chaos) and a new 4'th order oscillator with hyper-chaos....

  4. Phase noise and jitter modeling for fractional-N PLLs

    OpenAIRE

    S. A. Osmany; Herzel, F.; Schmalz, K; Winkler, W.

    2007-01-01

    We present an analytical phase noise model for fractional-N phase-locked loops (PLL) with emphasis on integrated RF synthesizers in the GHz range. The noise of the crystal reference, the voltage-controlled oscillator (VCO), the loop filter, the charge pump, and the sigma-delta modulator (SDM) is filtered by the PLL operation. We express the rms phase error (jitter) in terms of phase noise of the reference, the VCO phase noise and the third-order loop filter parameters. In addition, we conside...

  5. Phase noise analysis of clock recovery based on an optoelectronic phase-locked loop

    DEFF Research Database (Denmark)

    Zibar, Darko; Mørk, Jesper; Oxenløwe, Leif Katsuo

    2007-01-01

    A detailed theoretical analysis of a clock-recovery (CR) scheme based on an optoelectronic phase-locked loop is presented. The analysis emphasizes the phase noise performance, taking into account the noise of the input data signal, the local voltage-controlled oscillator (VCO), and the laser....... It is shown that a large loop length results in a higher timing jitter of the recovered clock signal. The impact of the loop length on the clock signal jitter can be reduced by using a low-noise VCO and a low loop filter bandwidth. Using the model, the timing jitter of the recovered optical and electrical...

  6. Method to VCO Linearization for FMCW Radar%一种FMCW雷达中的VCO非线性矫正方法

    Institute of Scientific and Technical Information of China (English)

    王旭刚; 夏伟杰

    2013-01-01

    调频连续波雷达(FMCW)的性能与压控振荡器(VCO)的调频线性度密切相关.通过提出VCO非线性问题,说明VCO的调频线性度对FMCW性能的影响,给出一种基于FPGA和DAC的VCO非线性矫正方法,对其矫正性能进行仿真验证,并且在Ka波段FMCW雷达平台上进行了实测验证,效果良好.

  7. Oscillating Permanent Magnets.

    Science.gov (United States)

    Michaelis, M. M.; Haines, C. M.

    1989-01-01

    Describes several ways to partially levitate permanent magnets. Computes field line geometries and oscillation frequencies. Provides several diagrams illustrating the mechanism of the oscillation. (YP)

  8. Solar neutrinos: Oscillations or No-oscillations?

    CERN Document Server

    Smirnov, A Yu

    2016-01-01

    The Nobel prize in physics 2015 has been awarded "... for the discovery of neutrino oscillations which show that neutrinos have mass". While SuperKamiokande (SK), indeed, has discovered oscillations, SNO observed effect of the adiabatic (almost non-oscillatory) flavor conversion of neutrinos in the matter of the Sun. Oscillations are irrelevant for solar neutrinos apart from small $\

  9. Novel Wien Bridge Oscillator Design Using Functional Block Structure with Current Conveyors

    Directory of Open Access Journals (Sweden)

    Pavel Brandstetter

    2012-01-01

    Full Text Available The purpose of this paper is to generally present possibilities of the current conveyor use in the well-known active electronic circuits. Current conveyors are able to substitute all known active elements. This claim is supported by the fact, that four basic functional block structures can be realized by use of current conveyors - voltage-controlled voltage source, voltage-controlled current source, current-controlled current source and current-controlled voltage source. The paper presents particular example of use of functional block structure with current conveyors in Wien bridge oscillator, where it successfully substitutes operational amplifier on the place of active element. Both theoretical formulae and design description are given. Finally, OrCAD PSpice simulation results are presented.

  10. Degraded Frequency-Tuning Range and Oscillation Amplitude of LC-VCOs due to the Nonquasi-Static Effect in MOS Varactors

    Science.gov (United States)

    Miyake, Masataka; Hori, Daisuke; Sadachika, Norio; Feldmann, Uwe; Miura-Mattausch, Mitiko; Mattausch, Hans Jürgen; Ohguro, Tatsuya; Iizuka, Takahiro; Taguchi, Masahiko; Miyamoto, Shunsuke

    Frequency dependent properties of accumulation-mode MOS varactors, which are key elements in many RF circuits, are dominated by Non-Quasi-Static (NQS) effects in the carrier transport. The circuit performances containing MOS varactors can hardly be reproduced without considering the NQS effect in MOS-varactor models. For the LC-VCO circuit as an example it is verified that frequency-tuning range and oscillation amplitude can be overestimated by over 20% and more than a factor 2, respectively, without inclusion of the NQS effect.

  11. Oscillations of Eccentric Pulsons

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Groenbech-Jensen, Niels; Lomdahl, Peter;

    1997-01-01

    Perturbation theory for elliptic pulsons is developed and predicts pulson and eccentricity oscillations. The pulson oscillation period is predicted qualitatively correct.......Perturbation theory for elliptic pulsons is developed and predicts pulson and eccentricity oscillations. The pulson oscillation period is predicted qualitatively correct....

  12. Design of an Output Feedback Controller for STATCOM in view of Low Frequency Oscillation Damping Using HBMO and PSO

    Directory of Open Access Journals (Sweden)

    masoud aliakbar golkar

    2011-11-01

    Full Text Available Nowadays since the speed of reaching to response is getting more important, the random searching algorithms are mostly used instead of the overall search of the problem space. This paper presents the application and the performance comparison of HBMO and PSO optimization techniques for designing an output feedback damping controller for STATCOM in order to enhance the damping of power system. The problem of the damping controller design is considered as an optimization problem with a multi-purpose criterion function and it is solved by HBMO and PSO algorithms. This controller is designed in order to transmit unstable electromechanical modes to the specific area of the complex plane. The proposed controller performance is confirmed by the analysis of the eigenvalue and nonlinear time-domain simulation under various disturbances with both control parameters of STATCOM (capacitor voltage control and terminal voltage control. Simulation results illustrate that the designed controller by HBMO performs better than PSO in finding the solution. Moreover, the design of the controller based on the capacitor voltage control in comparison with terminal voltage control has better low frequency oscillation damping and it increases the dynamical stability of the power system.

  13. Coordinated voltage control of a decoupled three-phase on load tap changer transformer and photovoltaic inverters for managing unbalanced networks

    DEFF Research Database (Denmark)

    Hu, Junjie; Marinelli, Mattia; Coppo, Massimiliano;

    2016-01-01

    phases. To address this problem, distribution transformers with single-phase tapping capability, together with reactive power provision of PV systems, are under investigation. This paper presents modeling and analysis of the benefits of coordinated voltage control of a decoupled three-phase on-load tap...... profiles on a real Danish distribution grid, as well as the developed dynamic photovoltaic generation and load models. The simulations show that the joint action of the power distribution transformer with OLTC control on each phase, and the reactive power provision of photovoltaic inverters, significantly...... improves the PV hosting capacity in the analyzed unbalanced scenarios without side effects, such as additional power losses, or significant neutral voltage rises...

  14. Compensation of negative sequence stator flux of doubly-fed induction generator using polar voltage control-based direct torque control under unbalanced grid voltage condition

    Directory of Open Access Journals (Sweden)

    Badrinarayan Bansilal Pimple

    2015-02-01

    Full Text Available This study proposes a polar voltage control-based direct torque control method to reduce the effects of unbalanced grid voltage on doubly-fed induction generator (DFIG-based wind turbine system. Under unbalanced grid voltage, the stator flux has a negative sequence component which leads to second harmonic pulsation in torque, stator active power, stator reactive power, stator current and rotor current. In the control scheme, the negative sequence rotor voltage vector is controlled to compensate the negative sequence stator flux by negative sequence rotor flux. Simulation study is carried out on a 2 MW DFIG system using MATLAB/SIMULINK. Feasibility of the proposed control strategy is experimentally verified on a 1.5 kW DFIG system.

  15. SoC-Based Output Voltage Control for BESS with a Lithium-Ion Battery in a Stand-Alone DC Microgrid

    Directory of Open Access Journals (Sweden)

    Seung-Yeong Yu

    2016-11-01

    Full Text Available This paper proposes a new DC output voltage control for a battery energy storage system (BESS with a lithium-ion battery based on the state of charge (SoC. The proposed control scheme was verified through computer simulations for a typical stand-alone DC microgrid, which consists of a BESS, photovoltaic (PV panel, engine generator (EG, and DC load. A scaled hardware prototype for a stand-alone DC microgrid was set up in the lab, in which the proposed control scheme was loaded in a DSP controller. The experimental results were compared with the simulation results for performance verification. The proposed control scheme provides relatively lower variation of the DC grid voltage than the conventional droop control.

  16. LC振荡器的设计要点%Design Issues for Cross-Coupled LC Oscillators

    Institute of Scientific and Technical Information of China (English)

    满家汉; 赵坤; 叶青

    2006-01-01

    This paper introduces design issues for cross-coupled LC oscillators. From a physical standpoint, the VCO topology, the amplitude of the tank, the noise source, the phase noise, and the Q factor of the tank are studied. According to these analyses,the design issues and constraints are presented. Finally, the simulation results of a cross-coupled LC oscillator are reported.%主要介绍了LC振荡器的设计要点.从LC振荡器的模型出发,研究了VCO的电路结构、谐振回路对于输出幅度的影响、VCO的噪声源、VCO的相位噪声以及谐振回路的Q值对于VCO的影响.给出了LC振荡器的设计要点及设计中需要考虑的约束条件.

  17. Using LabVIEW: Simulation Exciter of Devices Jamming

    OpenAIRE

    Elan Djaelani; Nina Siti Aminah; Ridodi Anantaprama

    2012-01-01

    It has been made exciter of devices jamming, by using component voltage controled oscilator (vco). It has been done measurements: signal noise,signal sawtooth and level DC voltage at those signals. Being wanted those devices jamming could be raised it’s performance. With helping software LabVIEW being made exciter. Result Simulation are graphic and table relation between input exciter and it’s output. Input exciter are: signal sawtooth, signal noise and level DC voltage that could be changing...

  18. Experimental demonstration of a noise-tunable delay line with applications to phase synchronization

    Science.gov (United States)

    Pessacg, F.; Taitz, A.; Patterson, G. A.; Fierens, P. I.; Grosz, D. F.

    2015-05-01

    In this paper we propose and demonstrate a discrete circuit capable of generating arbitrary time delays dependent on noise, either added externally or already present in the signal of interest due to a finite signal-to-noise ratio. We then go on to demonstrate an application to phase locking of signals by means of a standard Phase-Locked Loop (PLL) design, where the usual Voltage-Controlled Oscillator (VCO) is replaced by the noise-tunable delay line.

  19. 应用于WSN的0.5 V 4.8 GHz CMOS LC VCO设计%0.5 V 4.8 GHz CMOS LC VCO for WSN application

    Institute of Scientific and Technical Information of China (English)

    李智群; 赵晟

    2012-01-01

    为设计一个可应用于无线传感网的0.5V 4.8GHz CMOS LC压控振荡器,采用传统差分负阻结构的电感电容VCO核心电路,添加开关电容阵列增大VCO的调谐范围,利用升压电路和反相器的组合提高控制信号产生电路的性能,通过调节负阻管的宽长比等方法来优化VCO的相位噪声性能,保证VCO能在0.5V的低供电电压下稳定工作,相位噪声达到-119.3 dBc/Hz@1 MHz,VCO的频率调谐范围为4.3~5.3 GHz,相位噪声小于-115 dBc/Hz@1 MHz,最低可达-121.2 dBc/Hz@1 MHz,核心电路电流约为2.6 mA,满足无线传感网的应用要求.%A 0. 5 V 4. 8 GHz CMOS LC VCO for WSN application was designed. The VCO uses traditional differential negative-resistance structure. With a switched capacitor array, VCO achieves a large tuning range. Thanks to the combination of voltage-boosting circuit, VCO can have a control voltage larger than the supply voltage. Several technologies like width-length-ratio-adjusting of the transistors were used to optimize phase noise performance. The VCO uses 0. 13 μm. CMOS technology. The proposed VCO a-chieves a phase noise less than -115 dBc/Hz@l MHz, and -121. 2 dBc/Hz at most and consumes about 2. 6 mA core current at 0. 5 voltage supply. The performance of VCO meets the requirement of the design target.

  20. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  1. Phenomenology of neutrino oscillations

    Indian Academy of Sciences (India)

    G Rajasekaran

    2000-07-01

    The phenomenology of solar, atmospheric, supernova and laboratory neutrino oscillations is described. Analytical formulae for matter effects are reviewed. The results from oscillations are confronted with neutrinoless double beta decay.

  2. Quantum Duffing Oscillators

    OpenAIRE

    Sanin, A.; Semyonov, E.

    2012-01-01

    Numerical integration of the non-stationary Schrödinger equation with Duffing potential depending on two coordinates has been carried out. Oscillation types and the influence of coupling between two oscillators on frequency spectra are analyzed in detail.

  3. Performance Comparison of Bipolar Vs CMOS VCO in BiCMOS Technology%基于BiCMOS工艺的Bipolar VCO和CMOS VCO性能对比

    Institute of Scientific and Technical Information of China (English)

    欧阳宏志; 陈洪云; 苏旷宇

    2007-01-01

    阐述了基于BiCMOS工艺的全集成LC调谐压控振荡器的基本原理.为了比较Bipolar VCO和CMOS VCO的性能,他们很好地设计在同一块芯片上.在560M的中心频率上,CMOS VCO无论在功耗,还是在相位噪声方面都要优于Bipolar VCO,他们的电流消耗分别为3.9 mA和5.9 mA,两种VCO都是基于0.6 μm BiCMOS工艺而仿真和测量的.

  4. LC VCO相位噪声解析模型的分析%Analysis of Phase Noise Analytical Model in LC VCO

    Institute of Scientific and Technical Information of China (English)

    吴秀龙; 吴建辉; 吉新春; 陈军宁

    2010-01-01

    在无线射频接收机中,压控振荡器(VCO)的相位噪声对灵敏度影响很大,因此低相位噪声的VCO设计是人们研究的一个热点.在Hajimiri的相位噪声分析模型的基础上,提出了交叉耦合LC VCO的相位噪声解析模型,模型的计算结果与实际流片测试结果比较接近.该模型可以比较直观地观察相位噪声与电路参数的关系,对VCO的设计有一定的指导作用.

  5. 基于Verilog-A行为描述模型的VCO设计%Design of VCO based behavioral model using Verilog-A

    Institute of Scientific and Technical Information of China (English)

    刘帘曦; 杨银堂; 朱樟明; 付永朝

    2005-01-01

    分析了模拟硬件描述语言Verilog-A的特点,介绍了基于Verilog-A语言的行为级模拟电路设计过程.以锁相环(PLL)的子模块压控振荡器(VCO)的设计为例,建立了基于Verilog-A的行为模型进行系统设计的新方法.根据VCO的数学模型,建立了中心频率为120MHz的VCO行为模型,并利用Cadence Spectre仿真器对该模型进行了验证及PLL系统仿真.

  6. Neutrino Masses and Oscillations

    CERN Document Server

    Valle, J W F

    2005-01-01

    I summarize the status of three--neutrino oscillations that follow from combining the relevant world's data. The discussion includes the small parameters Delta_m-sol/Delta_m-atm and \\sin^2\\theta_{13}, which characterize the strength of CP violation in neutrino oscillations, the impact of oscillation data on the prospects for probing the absolute scale of neutrino mass in \

  7. The colpitts oscillator family

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, A.

    A tutorial study of the Colpitts oscillator family defined as all oscillators based on a nonlinear amplifier and a three- terminal linear resonance circuit with one coil and two capacitors. The original patents are investigated. The eigenvalues of the linearized Jacobian for oscillators based...

  8. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    . An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  9. Automated Voltage Control in LHCb

    CERN Document Server

    Granado Cardoso, L; Jacobsson, R

    2011-01-01

    LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

  10. Realization and Operation of Automatic Voltage Control in Dongguan Power Grid%东莞电网自动电压控制的实现与运行

    Institute of Scientific and Technical Information of China (English)

    言宇; 冯林桥

    2015-01-01

    Taking Dongguan power grid for example, this paper introduced the necessity to construct an automatic voltage control (AVC) system and expounded the implement method, control strategy and safety precautions of AVC. After the closed loop was put into operation, the voltage eligibility rate was improved and the power grid loss was reduced, which verifies the effectiveness of AVC function, to make the reactive voltage management of power grid realize safe, stable, high-quality and economic operation.%以东莞电网为例,介绍了建设自动电压控制(AVC)系统的必要性,并阐述了AVC系统实现的方法、控制策略及安全保障措施。经闭环投运,提高了电压合格率,降低了网损,验证了AVC功能的有效性,使电网无功电压管理真正实现了安全、稳定、优质、经济运行。

  11. Enhancement of voltage-controlled magnetic anisotropy through precise control of Mg insertion thickness at CoFeB|MgO interface

    Science.gov (United States)

    Li, Xiang; Fitzell, Kevin; Wu, Di; Karaba, C. Ty; Buditama, Abraham; Yu, Guoqiang; Wong, Kin L.; Altieri, Nicholas; Grezes, Cecile; Kioussis, Nicholas; Tolbert, Sarah; Zhang, Zongzhi; Chang, Jane P.; Khalili Amiri, Pedram; Wang, Kang L.

    2017-01-01

    We studied the impact of different insertion layers (Ta, Pt, and Mg) at the CoFeB|MgO interface on voltage-controlled magnetic anisotropy (VCMA) effect and other magnetic properties. Inserting a very thin Mg layer of 0.1-0.3 nm yielded a VCMA coefficient of 100 fJ/V-m, more than 3 times higher than the average values of around 30 fJ/V-m reported in Ta|CoFeB|MgO-based structures. Ta and Pt insertion layers also showed a small improvement, yielding VCMA coefficients around 40 fJ/V-m. Electrical, magnetic, and X-ray diffraction results reveal that a Mg insertion layer of around 1.2 nm gives rise to the highest perpendicular magnetic anisotropy, saturation magnetization, as well as the best CoFe and MgO crystallinity. Other Mg insertion thicknesses give rise to either under- or over-oxidation of the CoFe|MgO interface; a strong over-oxidation of the CoFe layer leads to the maximum VCMA effect. These results show that precise control over the Mg insertion thickness and CoFe oxidation level at the CoFeB|MgO interface is crucial for the development of electric-field-controlled perpendicular magnetic tunnel junctions with low write voltage.

  12. Neutrino oscillations: theory and phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Akhmedov, E.K., E-mail: akhmedov@ictp.trieste.it [Department of Theoretical Physics, Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm (Sweden)

    2011-12-15

    A brief overview of selected topics in the theory and phenomenology of neutrino oscillations is given. These include: oscillations in vacuum and in matter; phenomenology of 3-flavour neutrino oscillations; CP and T violation in neutrino oscillations in vacuum and in matter; matter effects on {nu}{sub {mu}}{r_reversible}{nu}{sub {tau}} oscillations; parametric resonance in neutrino oscillations inside the earth; oscillations below and above the MSW resonance; unsettled issues in the theory of neutrino oscillations.

  13. Covariant harmonic oscillators and coupled harmonic oscillators

    Science.gov (United States)

    Han, Daesoo; Kim, Young S.; Noz, Marilyn E.

    1995-01-01

    It is shown that the system of two coupled harmonic oscillators shares the basic symmetry properties with the covariant harmonic oscillator formalism which provides a concise description of the basic features of relativistic hadronic features observed in high-energy laboratories. It is shown also that the coupled oscillator system has the SL(4,r) symmetry in classical mechanics, while the present formulation of quantum mechanics can accommodate only the Sp(4,r) portion of the SL(4,r) symmetry. The possible role of the SL(4,r) symmetry in quantum mechanics is discussed.

  14. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  15. Microwave synthesizer using an on-chip Brillouin oscillator.

    Science.gov (United States)

    Li, Jiang; Lee, Hansuek; Vahala, Kerry J

    2013-01-01

    Low-phase-noise microwave oscillators are important to a wide range of subjects, including communications, radar and metrology. Photonic-based microwave-wave sources now provide record, close-to-carrier phase-noise performance, and compact sources using microcavities are available commercially. Photonics-based solutions address a challenging scaling problem in electronics, increasing attenuation with frequency. A second scaling challenge, however, is to maintain low phase noise in reduced form factor and even integrated systems. On this second front, there has been remarkable progress in the area of microcavity devices with large storage time (high optical quality factor). Here we report generation of highly coherent microwaves using a chip-based device that derives stability from high optical quality factor. The device has a record low electronic white-phase-noise floor for a microcavity-based oscillator and is used as the optical, voltage-controlled oscillator in the first demonstration of a photonic-based, microwave frequency synthesizer. The synthesizer performance is comparable to mid-range commercial devices.

  16. A memristor-based third-order oscillator: beyond oscillation

    KAUST Repository

    Talukdar, Abdul Hafiz Ibne

    2012-10-06

    This paper demonstrates the first third-order autonomous linear time variant circuit realization that enhances parametric oscillation through the usage of memristor in conventional oscillators. Although the output has sustained oscillation, the linear features of the conventional oscillators become time dependent. The poles oscillate in nonlinear behavior due to the oscillation of memristor resistance. The mathematical formulas as well as SPICE simulations are introduced for the memristor-based phase shift oscillator showing a great matching.

  17. Active battery charge equalization with voltage controlled vertical buck-boost switching cells%电压控制Buck-Boost电池充电均衡器

    Institute of Scientific and Technical Information of China (English)

    谢莉; 蒋伟

    2015-01-01

    本文研究了储能设备的均衡充电方法。采用垂直 Buck-Boost 电路作为均衡器的基本交换单元。在不同的负载条件下,用状态空间平均法和小信号分析法获得对应的开关单元模型。通过电压控制均衡方案,利用电压环补偿设备端电压,电流内环使得电荷定向移动。实验结果表明,所提出的均衡器能实现电荷最快移动并能有效地收敛到零电压差,本地控制器能快速、准确地跟踪参考值。%This paper investigates the active charge equalization method for energy storage devices. The vertical buck-boost circuit is used as the basic switching cell of this equalizer. By applying state-space averaging and small signal analysis, the model of the switching cell is obtained under different load condition. A voltage controlled equalization scheme is presented, which is featured with voltage loop to equalize the terminal voltage and inner current loop for charge shuttling. The simulation and experimental results indicate that the proposed equalizer can effectively converge to zero voltage difference condition by offering a maximized charge shuttling effort, and the local controller can react fast and precisely to the reference command.

  18. Oscillations of disks

    CERN Document Server

    Kato, Shoji

    2016-01-01

    This book presents the current state of research on disk oscillation theory, focusing on relativistic disks and tidally deformed disks. Since the launch of the Rossi X-ray Timing Explorer (RXTE) in 1996, many high-frequency quasiperiodic oscillations (HFQPOs) have been observed in X-ray binaries. Subsequently, similar quasi-periodic oscillations have been found in such relativistic objects as microquasars, ultra-luminous X-ray sources, and galactic nuclei. One of the most promising explanations of their origin is based on oscillations in relativistic disks, and a new field called discoseismology is currently developing. After reviewing observational aspects, the book presents the basic characteristics of disk oscillations, especially focusing on those in relativistic disks. Relativistic disks are essentially different from Newtonian disks in terms of several basic characteristics of their disk oscillations, including the radial distributions of epicyclic frequencies. In order to understand the basic processes...

  19. Self-oscillation

    Science.gov (United States)

    Jenkins, Alejandro

    2013-04-01

    Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain dynamical systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy into the vibration: no external rate needs to be adjusted to the resonant frequency. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the swaying of the London Millennium Footbridge in 2000. Clocks are self-oscillators, as are bowed and wind musical instruments. The heart is a “relaxation oscillator”, i.e., a non-sinusoidal self-oscillator whose period is determined by sudden, nonlinear switching at thresholds. We review the general criterion that determines whether a linear system can self-oscillate. We then describe the limiting cycles of the simplest nonlinear self-oscillators, as well as the ability of two or more coupled self-oscillators to become spontaneously synchronized (“entrained”). We characterize the operation of motors as self-oscillation and prove a theorem about their limit efficiency, of which Carnot’s theorem for heat engines appears as a special case. We briefly discuss how self-oscillation applies to servomechanisms, Cepheid variable stars, lasers, and the macroeconomic business cycle, among other applications. Our emphasis throughout is on the energetics of self-oscillation, often neglected by the literature on nonlinear dynamical systems.

  20. Mechanism of Voltage Control Mismatch Between Provincial Power Grid and Regional Power Network and Its Three-Dimensional Analysis%省地电压调控失配机理与三维分析方法

    Institute of Scientific and Technical Information of China (English)

    李剑辉; 林建熙; 吴国炳; 杨银国; 张勇军; 蔡泽祥

    2013-01-01

      大电网发展的耦合化、容性化,使得电力系统无功电压调控的难度越来越大,具体表现为省地电网间的调控失配问题。考虑分级调度机制的影响,对调控失配问题进行机理分析,得到调控目标、调控需求与调控能力之间的配合特性,提出三维分析方法,从空间、时间与目标3个维度上剖析省地调控配合的关系,得到调控失配问题的解决思路与方向。结合AVC/VQC控制的特点,在就地校正控制中引入变压器高压侧电压判据,兼顾上下层调控的需求,优化调控效果。实例分析验证了解决思路与解决策略的合理性与有效性。%  The close-coupled and high-capacitive characters of large-scale power grid are concomitant with its development, it make the reactive power and voltage control more difficult, and as a result the mismatching between voltage control in provincial power grid and that in regional power network appears. Considering the influence of hierarchical scheduling mechanism, the voltage control mismatching is analyzed to obtain the coordination characteristics among control objective, control demand and control capability. A three-dimensional analysis method is proposed to dissect the coordination relation between the voltage control of provincial power grid and that of regional power network in three dimensionalities of space, time and objective and to attain the thinking for the solution of the control mismatching. Combining with the features of AVC/VQC control, a voltage criterion at the 220kV side of transformers in the substations is led into the local corrective control to consider the demands from voltage control in power grid and that in power network to optimize the result of voltage control. The effectiveness and reasonableness of the thinking and strategy to solve this problem are verified by case study.

  1. The Effectiveness of Extract Snack Head Fish and Virgin Coconut Oil (VCO on Sputum Conversion and Levels of Interferon-ɣ in Patients with Pulmonary TB Multi Drug Resistant (MDR in Labuang Baji Hospital Makassar

    Directory of Open Access Journals (Sweden)

    Freddy Chandra Montolalu

    2016-12-01

    Full Text Available Treatment of pulmonary MDR TB disease is relatively very expensive and takes a long time to heal, This study aims to determine the effect of treatment DOTS-Plus capsules supplemented catfish albumin protein coupled VCO can affect the conversion of sputum smear and levels of interferon-ɣ in pulmonary MDR TB patients who received treatment DOTS-Plus in Labuang Baji Hospital, Makassar. This study is a quantitative study with randomized controlled quasi-experimental approach with a sample size of 30 people (15 experimental, 15 control. Data analysis was done using the Independent Sample T Test with a confidence level of 95%. All the data were Analyzed by SPSS software, version 21.0 (SPSS, Inc., Chicago, IL. All the groups in which I no conversion. The intervention began in the second conversion of 80% and all had more conversions in III. Control in II started there is a conversion of 53.3% and until VI there are still 3.3% which is not convertible. The average levels of interferon gamma first month (intervention: 153.26 ± 27.19; control 150.60 ± 29.55, three month (intervention: 179.00 ± 48.89; control: 140.46 ± 20, 03 . Sixth months (intervention: 152.00 ± 70.74; Controls: 150.93 ± 18.65. The results showed pulmonary MDR TB patients receive treatment DOTS Plus capsules albumin supplemented catfish coupled VCO accelerate the conversion of sputum (p = 0.038 and improve the levels of interferon-ɣ (p = 0.011. In conclusion, MDR pulmonary tuberculosis patients received treatment DOTS Plus capsules albumin supplemented catfish plus VCO will accelerate the conversion of sputum, improve levels of interferon-ɣ. By him that, to be considered for albumin supplementation capsules catfish coupled VCO in the treatment of pulmonary tuberculosis.

  2. Fully Integrated 1.7GHz, 188dBc/Hz FoM, 0.8V, 320uW LC-tank VCO and Frequency Divider

    DEFF Research Database (Denmark)

    Midtgaard, Jesper Stolpe; Jeppesen, Thomas; Christensen, Kåre Tais;

    2005-01-01

    This paper presents a 0.13μm CMOS 1.7GHz VCO with frequency divider, suitable for ultra-low-power hearing-aid applications. The circuit has a 16% tuning range, a minimum power consumption of 320μW from a 0.8V power supply, power-supply and temperature compensation, an excellent 188dBc/Hz figure...

  3. A one-dimensional model illustrating virtual-cathode formation in a novel coaxial virtual-cathode oscillator

    Science.gov (United States)

    Turner, Geoffrey R.

    2014-09-01

    A one-dimensional electrostatic sheet model of a coaxial geometry Virtual Cathode Oscillator (VCO) is presented. The cathode is centrally located and connects to a peripherally located plate electrode to form a resonant cavity, and is thus considered to be a novel design. Charge is modelled as concentric sheets about the cathode whose absolute position and velocity are determined as a function of time by solving the relativistic equations of motion. The model predicts the formation of a virtual cathode between the grid and plate electrodes for the case of a space-charge limited current. Setting the electron reflexing frequency (as a function of the grid potential) comparable with the cavity resonant frequency is predicted to improve the efficiency of microwave emission.

  4. A one-dimensional model illustrating virtual-cathode formation in a novel coaxial virtual-cathode oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Geoffrey R., E-mail: gturner@csir.co.za [Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001 (South Africa)

    2014-09-15

    A one-dimensional electrostatic sheet model of a coaxial geometry Virtual Cathode Oscillator (VCO) is presented. The cathode is centrally located and connects to a peripherally located plate electrode to form a resonant cavity, and is thus considered to be a novel design. Charge is modelled as concentric sheets about the cathode whose absolute position and velocity are determined as a function of time by solving the relativistic equations of motion. The model predicts the formation of a virtual cathode between the grid and plate electrodes for the case of a space-charge limited current. Setting the electron reflexing frequency (as a function of the grid potential) comparable with the cavity resonant frequency is predicted to improve the efficiency of microwave emission.

  5. 提高RF MEMS开关速度的电压控制方法%Voltage Control Approach to Improve the Speed of RF MEMS Switches

    Institute of Scientific and Technical Information of China (English)

    邓成; 鲍景富; 凌源; 杜亦佳; 赵兴海; 郑英彬

    2012-01-01

    针对RF MEMS开关释放时间过长的问题,提出了一种电压控制方法有效地缩短了开关的释放时间,提高了开关的速度.这种方法无需修改器件设计,仅需要调整偏置电压变化形式,用线性压降替代传统的阶跃压降,就能有效抑制MEMS梁在释放过程中的振动.给出了这种方法的相关理论、等效模型及仿真结果.由ANSYS仿真结果可知,在标准大气压下,采用28 μs单段线性压降后,梁的释放时间从103 μs缩短到62.5 μs;采用26 μs双段线性压降后,梁的释放时间进一步缩短到26 μs,仅为原来的1/4,即开关速度约为原来的4倍.%The voltage control approach was presented to shorten the release time of the RF MEMS switch effectively, and the switching speed was improved. This method can inhibit the MEMS beam vibration in the release process effectively, which does not need to modify the device design, only need to adjust the bias voltage changing form and replace the traditional step representation pressure drop with the linear pressure drop. The correlation theory, equivalent model and simulation result of the approach were given. The ANSYS simulation results indicate that in the standard atmospheric pressure, the beam release time reduces from 103 jxs to 62. 5 ^s with 28 /is single ramped bias voltage drop? And the beam release time furtherly reduces to 26 /us with 26 pis double ramped bias voltage drops, which is a quarter of the original release time, that is, the speed of the switch is about four times of the original speed.

  6. Cathodic voltage-controlled electrical stimulation of titanium for prevention of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii biofilm infections.

    Science.gov (United States)

    Canty, Mary; Luke-Marshall, Nicole; Campagnari, Anthony; Ehrensberger, Mark

    2017-01-15

    Antibiotic resistance of bacterial biofilms limits available treatment methods for implant-associated orthopaedic infections. This study evaluated the effects of applying cathodic voltage-controlled electrical stimulations (CVCES) of -1.5V and -1.8V (vs. Ag/AgCl) to coupons of commercially pure titanium (cpTi) incubated in cultures of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii (A. baumannii) as a method of preventing bacterial attachment. Stimulations were applied for 2, 4, and 8h and coupon-associated and planktonic colony-forming units (CFU) were enumerated following stimulation. Compared to open circuit potential (OCP) controls, CVCES for 4h at -1.8V significantly reduced coupon-associated MRSA CFU by 99.9% (1.30×10(4)vs. 4.45×10(7), p=0.047) and A. baumannii coupon-associated CFU by 99.9% (1.64×10(4)vs. 5.93×10(7), p=0.001) and reduced planktonic CFU below detectable levels for both strains. CVCES at -1.8V for 8h also reduced coupon-associated and planktonic CFU below detectable levels for each strain. CVCES at -1.5V for 4 and 8h, and -1.8V for 2h did not result in clinically relevant reductions. For 4 and 8h stimulations, the current density was significantly higher for -1.8V than -1.5V, an effect directly related to the rate of water and oxygen reduction on the cpTi surface. This significantly increased the pH, a suspected influence in decreased CFU viability. The voltage-dependent electrochemical properties of cpTi likely contribute to the observed antimicrobial effects of CVCES. This study revealed that CVCES of titanium could prevent coupon-associated and planktonic CFU of Gram-positive MRSA and Gram-negative A. baumannii from reaching detectable levels in a magnitude-dependent and time-dependent manner.

  7. Hyperchaotic Oscillator with Gyrators

    DEFF Research Database (Denmark)

    Tamasevicius, A; Cenys, A; Mykolaitis, G.

    1997-01-01

    A fourth-order hyperchaotic oscillator is described. It contains a negative impedance converter, two gyratots, two capacitors and a diode. The dynamics of the oscillator is shown to be characterised by two positive Lyapunov exponents. The performance of the circuit is investigated by means...

  8. Convection and oscillations

    CERN Document Server

    Houdek, G

    2010-01-01

    In this short review on stellar convection dynamics I address the following, currently very topical, issues: (1) the surface effects of the Reynolds stresses and nonadiabaticity on solar-like pulsation frequencies, and (2) oscillation mode lifetimes of stochastically excited oscillations in red giants computed with different time-dependent convection formulations.

  9. Oscillations at low energies

    CERN Document Server

    Dwyer, D A

    2015-01-01

    A concise summary of the "Oscillation at low energies" parallel session at the 2014 Neutrino Oscillation Workshop is provided. Plans to use man-made neutrinos and antineutrinos to determine the neutrino mass hierarchy, search for sterile neutrinos, and to observe coherent neutrino-nucleus scattering were discussed. Potential measurements of solar neutrinos, supernova neutrinos, and geoneutrinos are also summarized.

  10. Hyperchaotic Oscillator with Gyrators

    DEFF Research Database (Denmark)

    Tamasevicius, A; Cenys, A; Mykolaitis, G.;

    1997-01-01

    A fourth-order hyperchaotic oscillator is described. It contains a negative impedance converter, two gyratots, two capacitors and a diode. The dynamics of the oscillator is shown to be characterised by two positive Lyapunov exponents. The performance of the circuit is investigated by means...

  11. On the Dirac oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, R. de Lima [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Centro de Tecnologia. Unidade Academica de Educacao]. E-mail: rafael@df.ufcg.edu.br; rafaelr@cbpf.br

    2007-07-01

    In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra C 7. The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit. (author)

  12. Disentangling neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Andrew G. [Physics Department, Boston University, Boston, MA 02215 (United States)], E-mail: cohen@bu.edu; Glashow, Sheldon L. [Physics Department, Boston University, Boston, MA 02215 (United States)], E-mail: slg@bu.edu; Ligeti, Zoltan [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)], E-mail: ligeti@lbl.gov

    2009-07-13

    The theory underlying neutrino oscillations has been described at length in the literature. The neutrino state produced by a weak decay is usually portrayed as a linear superposition of mass eigenstates with, variously, equal energies or equal momenta. We point out that such a description is incorrect, that in fact, the neutrino is entangled with the other particle or particles emerging from the decay. We offer an analysis of oscillation phenomena involving neutrinos (applying equally well to neutral mesons) that takes entanglement into account. Thereby we present a theoretically sound proof of the universal validity of the oscillation formulae ordinarily used. In so doing, we show that the departures from exponential decay reported by the GSI experiment cannot be attributed to neutrino mixing. Furthermore, we demonstrate that the 'Moessbauer' neutrino oscillation experiment proposed by Raghavan, while technically challenging, is correctly and unambiguously describable by means of the usual oscillation formalae.

  13. A Design of VCO for Controller of Gigabit Ethernet%一种千兆以太网控制器中VCO的设计

    Institute of Scientific and Technical Information of China (English)

    唐路; 王志功; 赵文虎

    2004-01-01

    随着通信网络技术的迅速发展,以太网技术得到了广泛的运用.千兆以太网是以太网的一种,作为一种新的网络体系,千兆以太网已成为组建局域网的首选方案.本文中所提出的VCO(压控振荡器)是千兆以太网控制器中PLL(锁相环)的一个部分.由于VCO决定了控制器的工作速率,因此VCO的设计是千兆以太网控制器设计的关键.本文给出了VCO的电路仿真的结果与设计出的版图,并对电路与版图的设计方法进行了探讨.本文中所设计的VCO采用了TSMC 0.25μm CMOS工艺实现,中心振荡频率为1.25GHz,输出电压的幅度为620mV,版图的面积为100×100μm2.

  14. 一种高性能宽带LC VCO的设计%Design of a High Performance LC VCO for Broadband Application

    Institute of Scientific and Technical Information of China (English)

    戴惜时

    2014-01-01

    基于TSMC 65 nm CMOS工艺,采用电流偏置型差分负阻结构,设计了一个宽频率覆盖范围(7.6~10.7 GHz)的电感电容谐振压控振荡器(LC VCO).采用差分控制电压方式,减小共模噪声对VCO性能的影响.采用三组可变电容共同作用的方式,减小VCO增益随振荡频率的变化,同时实现频率的温度补偿.创新性地采用一种新型开关结构,在基本不增加面积的情况下,优化了LC VCO的相位噪声性能.将该LC VCO用于为4.2~5 GHz双沿采样DAC提供时钟的锁相环电路,实现了良好的相位噪声性能.

  15. Effect of embedded voltage source converter on power system oscillation damping

    Institute of Scientific and Technical Information of China (English)

    R; DUNN

    2010-01-01

    This paper presents the damping torque analysis of power system oscillation stability as affected by the dynamic and control functions of an embedded voltage source converter(VSC).The objective of the study is to explain why and how the dynamic and basic control functions of the embedded VSC,ac and dc voltage regulation,provide damping to power system oscillations.The most important conclusion obtained in the paper is that both the dynamics and the dc voltage control of the VSC contribute a variable damping torque,which can be positive or negative,at different levels of system load conditions.More positive damping torque can be provided by the VSC at a heavier load condition.There exists a point of system load condition where the VSC provides no damping torque to power system oscillation hence dose not impose any influence on power system oscillation stability.The VSC studied in the paper can be the power-electronics-based interface of various FACTS(flexible ac transmission systems) devices,energy storage systems and renewable power generation units,although the focus of the discussion presented in this paper is the effect of the dynamics and basic control functions of the VSC themselves on power system oscillation damping.To demonstrate the analytical conclusions obtained in the paper,results of eigenvalue computation and nonlinear simulation of an example power system with STATCOM(static synchronous compensator) are given.

  16. Boxing with neutrino oscillations

    Science.gov (United States)

    Wagner, D. J.; Weiler, Thomas J.

    1999-06-01

    We develop a characterization of neutrino oscillations based on the coefficients of the oscillating terms. These coefficients are individually observable; although they are quartic in the elements of the unitary mixing matrix, they are independent of the conventions chosen for the angle and phase parametrization of the mixing matrix. We call these reparametrization-invariant observables ``boxes'' because of their geometric relation to the mixing matrix, and because of their association with the Feynman box diagram that describes oscillations in field theory. The real parts of the boxes are the coefficients for the CP- or T-even oscillation modes, while the imaginary parts are the coefficients for the CP- or T-odd oscillation modes. Oscillation probabilities are linear in the boxes, so measurements can straightforwardly determine values for the boxes (which can then be manipulated to yield magnitudes of mixing matrix elements). We examine the effects of unitarity on the boxes and discuss the reduction of the number of boxes to a minimum basis set. For the three-generation case, we explicitly construct the basis. Using the box algebra, we show that CP violation may be inferred from measurements of neutrino flavor mixing even when the oscillatory factors have averaged. The framework presented here will facilitate general analyses of neutrino oscillations among n>=3 flavors.

  17. Quasi-Fibonacci oscillators

    CERN Document Server

    Gavrilik, A M; Rebesh, A P

    2010-01-01

    We study the properties of sequences of the energy eigenvalues for some generalizations of q-deformed oscillators including the p,q-oscillator, the 3-, 4- and 5-parameter deformed oscillators given in the literature. It is shown that most of the considered models belong to the class of so-called Fibonacci oscillators for which any three consequtive energy levels satisfy the relation E_{n+1}=\\lambda E_n+\\rho E_{n-1} with real constants \\lambda, \\rho. On the other hand, for certain \\mu-oscillator known from 1993 we prove the fact of its non-Fibonacci nature. Possible generalizations of the three-term Fibonacci relation are discussed among which for the \\mu$-oscillator we choose, as the most adequate, the so-called quasi-Fibonacci (or local Fibonacci) property of the energy levels. The property is encoded in the three-term quasi-Fibonacci (QF) relation with non-constant, n-dependent coefficients \\lambda and \\rho. Various aspects of the QF relation are elaborated for the \\mu-oscillator and some of its extensions.

  18. Quasi-Fibonacci oscillators

    Science.gov (United States)

    Gavrilik, A. M.; Kachurik, I. I.; Rebesh, A. P.

    2010-06-01

    We study the properties of the sequences of the energy eigenvalues for some generalizations of q-deformed oscillators including the p, q-oscillator, and the three-, four- and five-parameter deformed oscillators given in the literature. It is shown that most of the considered models belong to the class of so-called Fibonacci oscillators for which any three consecutive energy levels satisfy the relation En + 1 = λEn + ρEn - 1 with real constants λ, ρ. On the other hand, for a certain μ-oscillator known since 1993, we prove its non-Fibonacci nature. Possible generalizations of the three-term Fibonacci relation are discussed, among which for the μ-oscillator we choose, as the most adequate, the so-called quasi-Fibonacci (or local Fibonacci) property of the energy levels. The property is encoded in the three-term quasi-Fibonacci (QF) relation with the non-constant, n-dependent coefficients λ and ρ. Various aspects of the QF relation are elaborated for the μ-oscillator and some of its extensions.

  19. Oscillating Filaments: I - Oscillation and Geometrical Fragmentation

    CERN Document Server

    Gritschneder, Matthias; Burkert, Andreas

    2016-01-01

    We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid based AMR-code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, e.g. with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process `geometrical fragmentation'. In our realization the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristical scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. ...

  20. Synchronization of hyperchaotic oscillators

    DEFF Research Database (Denmark)

    Tamasevicius, A.; Cenys, A.; Mykolaitis, G.

    1997-01-01

    Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...

  1. Neutrino anomalies without oscillations

    Indian Academy of Sciences (India)

    Sandip Pakvasa

    2000-01-01

    I review explanations for the three neutrino anomalies (solar, atmospheric and LSND) which go beyond the `conventional' neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well.

  2. High frequency nanotube oscillator

    Science.gov (United States)

    Peng, Haibing [Houston, TX; Zettl, Alexander K [Kensington, TX

    2012-02-21

    A tunable nanostructure such as a nanotube is used to make an electromechanical oscillator. The mechanically oscillating nanotube can be provided with inertial clamps in the form of metal beads. The metal beads serve to clamp the nanotube so that the fundamental resonance frequency is in the microwave range, i.e., greater than at least 1 GHz, and up to 4 GHz and beyond. An electric current can be run through the nanotube to cause the metal beads to move along the nanotube and changing the length of the intervening nanotube segments. The oscillator can operate at ambient temperature and in air without significant loss of resonance quality. The nanotube is can be fabricated in a semiconductor style process and the device can be provided with source, drain, and gate electrodes, which may be connected to appropriate circuitry for driving and measuring the oscillation. Novel driving and measuring circuits are also disclosed.

  3. Neural Oscillators Programming Simplified

    Directory of Open Access Journals (Sweden)

    Patrick McDowell

    2012-01-01

    Full Text Available The neurological mechanism used for generating rhythmic patterns for functions such as swallowing, walking, and chewing has been modeled computationally by the neural oscillator. It has been widely studied by biologists to model various aspects of organisms and by computer scientists and robotics engineers as a method for controlling and coordinating the gaits of walking robots. Although there has been significant study in this area, it is difficult to find basic guidelines for programming neural oscillators. In this paper, the authors approach neural oscillators from a programmer’s point of view, providing background and examples for developing neural oscillators to generate rhythmic patterns that can be used in biological modeling and robotics applications.

  4. Atmospheric neutrino oscillations

    CERN Document Server

    Giacomelli, G; Antolini, R; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Cafagna, F; Campana, D; Carboni, M; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; Dekhissi, H; De Marzo, C; De Mitri, I; Derkauoi, J; De Vincenzi, M; Di Credico, A; Esposito, L; Forti, C; Fusco, P; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Mazziotta, M N; Mengucci, A; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R

    2005-01-01

    The latest results from the Soudan 2, MACRO and SuperKamiokande experiments on atmospheric neutrino oscillations are summarised and discussed. In particular a discussion is made on the Monte Carlo simulations used for the atmospheric neutrino flux.

  5. Oscillations in counting statistics

    CERN Document Server

    Wilk, Grzegorz

    2016-01-01

    The very large transverse momenta and large multiplicities available in present LHC experiments on pp collisions allow a much closer look at the corresponding distributions. Some time ago we discussed a possible physical meaning of apparent log-periodic oscillations showing up in p_T distributions (suggesting that the exponent of the observed power-like behavior is complex). In this talk we concentrate on another example of oscillations, this time connected with multiplicity distributions P(N). We argue that some combinations of the experimentally measured values of P(N) (satisfying the recurrence relations used in the description of cascade-stochastic processes in quantum optics) exhibit distinct oscillatory behavior, not observed in the usual Negative Binomial Distributions used to fit data. These oscillations provide yet another example of oscillations seen in counting statistics in many different, apparently very disparate branches of physics further demonstrating the universality of this phenomenon.

  6. Oscillating Filaments. I. Oscillation and Geometrical Fragmentation

    Science.gov (United States)

    Gritschneder, Matthias; Heigl, Stefan; Burkert, Andreas

    2017-01-01

    We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid-based AMR code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, such as with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation, and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process “geometrical fragmentation.” In our realization, the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristic scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. We show that the overall oscillation pattern can hide the infall signature of cores.

  7. Indirect neutrino oscillations

    CERN Document Server

    Babu, K S; Wilczek, Frank; Pati, Jogesh C; Wilczek, Frank

    1995-01-01

    We show how two different scales for oscillations between e and \\mu neutrinos, characterized by different mixing angles and effective mass scales, can arise in a simple and theoretically attractive framework. One scale characterizes direct oscillations, which can accommodate the MSW approach to the solar neutrino problem, whereas the other can be considered as arising indirectly, through virtual transitions involving the \\tau neutrino with a mass \\sim 1 eV. This indirect transition allows the possibility of observable \\bar \

  8. Neutrino Oscillation Physics

    OpenAIRE

    Kayser, Boris

    2012-01-01

    To complement the neutrino-physics lectures given at the 2011 International School on Astro Particle Physics devoted to Neutrino Physics and Astrophysics (ISAPP 2011; Varenna, Italy), at the 2011 European School of High Energy Physics (ESHEP 2011; Cheila Gradistei, Romania), and, in modified form, at other summer schools, we present here a written description of the physics of neutrino oscillation. This description is centered on a new way of deriving the oscillation probability. We also prov...

  9. Ultrastable Multigigahertz Photonic Oscillator

    Science.gov (United States)

    Logan, Ronald T., Jr.

    1996-01-01

    Novel photonic oscillator developed to serve as ultrastable source of microwave and millimeter-wave signals. In system, oscillations generated photonically, then converted to electronic form. Includes self-mode-locked semiconductor laser producing stream of pulses, detected and fed back to laser as input. System also includes fiber-optic-delay-line discriminator, which detects fluctuations of self-mode-locking frequency and generates error signal used in negative-feedback loop to stabilize pulse-repetition frequency.

  10. The Liege Oscillation Code

    CERN Document Server

    Scuflaire, R; Théado, S; Bourge, P -O; Miglio, A; Godart, M; Thoul, A; Noels, A

    2007-01-01

    The Liege Oscillation code can be used as a stand-alone program or as a library of subroutines that the user calls from a Fortran main program of his own to compute radial and non-radial adiabatic oscillations of stellar models. We describe the variables and the equations used by the program and the methods used to solve them. A brief account is given of the use and the output of the program.

  11. Self-oscillation

    CERN Document Server

    Jenkins, Alejandro

    2011-01-01

    Physicists are very familiar with forced and parametric resonance, but usually not with self-oscillation, a property of certain linear systems that gives rise to a great variety of vibrations, both useful and destructive. In a self-oscillator, the driving force is controlled by the oscillation itself so that it acts in phase with the velocity, causing a negative damping that feeds energy from the environment into the vibration: no external rate needs to be tuned to the resonant frequency. A paper from 1830 by G. B. Airy gives us the opening to introduce self-oscillation as a sort of "perpetual motion" responsible for the human voice. The famous collapse of the Tacoma Narrows bridge in 1940, often attributed by introductory physics texts to forced resonance, was actually a self-oscillation, as was the more recent swaying of the London Millenium Footbridge. Clocks are self-oscillators, as are bowed and wind musical instruments, and the heartbeat. We review the criterion that determines whether an arbitrary line...

  12. Frequency of self-oscillations

    CERN Document Server

    Groszkowski, Janusz

    2013-01-01

    Frequency of Self-Oscillations covers the realm of electric oscillations that plays an important role both in the scientific and technical aspects. This book is composed of nine chapters, and begins with the introduction to the alternating currents and oscillation. The succeeding chapters deal with the free oscillations in linear isolated systems. These topics are followed by discussions on self-oscillations in linear systems. Other chapters describe the self-oscillations in non-linear systems, the influence of linear elements on frequency of oscillations, and the electro mechanical oscillato

  13. The active-bridge oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Wessendorf, K.O.

    1998-07-01

    This paper describes the Active-Bridge Oscillator (ABO), a new concept in high-stability oscillator design. The ABO is ab ridge-type oscillator design that is easly to design and overcomes many of the operational and design difficulties associated with standard bridge oscillator designs. The ABO will oscillate with a very stable output amplitude over a wide range of operating conditions without the use of an automatic-level-control (ALC). A standard bridge oscillator design requires an ALC to maintain the desired amplitude of oscillation. for this and other reasons, bridge oscilaltors are not used in mainstream designs. Bridge oscillators are generally relegated to relatively low-volume, high-performance applications. The Colpitts and Pierce designs are the most popular oscillators but are typically less stable than a bridge-type oscillator.

  14. Integrated VCOs for Medical Implant Transceivers

    Directory of Open Access Journals (Sweden)

    Ahmet Tekin

    2008-01-01

    Full Text Available The 402–405 MHz medical implant communication service (MICS band has recently been allocated by the US Federal Communication Commission (FCC with the potential to replace the low-frequency inductive coupling techniques in implantable devices. This band was particularly chosen to provide full-integration, low-power, faster data transfer, and longer communication range. This paper investigates the design of a voltage-controlled oscillator (VCO that will be an essential building block of such wireless implantable devices operating in the MICS service band. Three different integrated quadrature VCOs that meet the requirements of the MICS standard are designed in 0.18 μm TSMC CMOS process to propose an optimum choice. Their performances in terms of power consumption, die area, linearity, and phase noise are compared. The fabricated VCOs are a four-stage differential ring VCO, an LC tank VCO directly loaded with a poly-phase filter, and an 800 MHz LC tank VCO with a high-frequency master-slave divider. All three architectures target a VCO gain of Kvco = 15 MHz/V with 3 calibration control and 2 frequency-shift keying (FSK control signals and are designed for 1.5 V supply voltage in a 0.18-μm standard CMOS process.

  15. Coalescence in coupled Duffing oscillators

    Institute of Scientific and Technical Information of China (English)

    YANG Jun-Zhong

    2009-01-01

    The forced Duffing oscillator has a pair of symmetrical attractors in a proper parameter regime. When a lot of Duffing oscillators are coupled linearly, the system tends to form clusters in which the neighboring oscillators fall onto the same attractor. When the coupling strength is strong, all of the oscillators fall onto one attractor. In this work, we investigate coalescence in the coupled forced Duffing oscillators. Some phenomena are found and explanations are presented.

  16. 大型光伏电站无功电压控制研究%Research on reactive power and voltage control of large-scale photovoltaic power station

    Institute of Scientific and Technical Information of China (English)

    葛虎; 毕锐; 徐志成; 丁明; 任轲轲

    2014-01-01

    To satisfy reactive power and voltage control requirements of grid-connectedphotovoltaic power station, setting the qualified voltage and power factor at the PCC as the optimal control objective, strategies based on nine-zone diagram for reactive power and voltage control are proposed to PQ-type and PV-type photovoltaic power stations. Equivalent models of PQ-type and PV-type photovoltaic power stations are built and the flowcharts for reactive power and voltage control strategies are presented. Based on the typical dynamic changes of photovoltaic power station output and load, a 110 kV system with large-scale photovoltaic power station for reactive power and voltage control is given and the results of simulation show that the proposed strategies are effective and practical. This work is supported by National High-tech R & D Program of China (863 Program) (No. 2011AA05A107).%为了满足光伏电站并网对公共连接点(Point of common coupling, PCC)无功电压控制要求,基于九区图原理,以PCC电压和功率因数均合格为最优控制目标,针对PQ电源型和PV电源型的大型光伏电站提出了的无功电压控制策略。搭建了PQ电源型和PV电源型大型光伏电站的等效模型,给出光伏电站无功电压控制策略实施流程图。以典型光伏电站出力和负荷动态变化为基础,通过搭建一个含大型并网光伏电站的110 kV系统,对光伏电站的无功电压控制进行仿真。仿真结果验证了所提策略的有效性和实用性。

  17. Noise in Advanced Electronic Devices and Circuits

    Science.gov (United States)

    Deen, M. Jamal; Marinov, O.

    2005-08-01

    State-of-the-art low-frequency and high-frequency noise performance and modeling in modern semiconductor devices and circuits are discussed. The increase of noise-to-DC current ratio may compromise the circuit applications in near future. The low-frequency noise (LFN) tends to a log-normal distribution. Since the random-telegraph-signal (RTS) noise is pronounced in submicron devices, then new techniques being used to characterize of multilevel RTS are discussed. High-frequency noise modeling and sample experimental results are presented, including the important effect of gate-tunneling current for future devices. For the RF circuits, we discuss the phase noise in voltage-controlled oscillators (VCO) based on ring oscillators and LC-tank VCOs with and without automatic amplitude control. Finally, the effects of hot-carrier stress on the performance of a VCO is presented and discussed.

  18. A 0.18 μm p-MOSFET large-signal RF model and its application on MMIC design

    Science.gov (United States)

    Ho, Chien-Chih; Kuo, Chin-Wei; Hsiao, Chao-Chih; Chan, Yi-Jen

    2003-06-01

    A modified 0.18 μm gate-length p-channel MOSFET large-signal rf model, based on the BSIM3v3 model, is presented in this report which achieves a good agreement with the device performance. This large-signal rf model includes the required passive components to fit the device dc and rf characteristics. To verify this modified model, the microwave load-pull and digital modulation evaluation have been conducted and compared them with the model predictions, where a good agreement has been reached for this 0.18 μm p-MOSFET. A 2.4 GHz fully integrated PMOS voltage-controlled oscillator (VCO) MMIC was designed based on this modified model. An accurate prediction of oscillation frequencies and output power levels of this 2.4 GHz PMOS VCO can be achieved, which demonstrates that the modified rf large-signal model can be applied for microwave circuit design.

  19. Finite q-oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Atakishiyev, Natig M [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Klimyk, Anatoliy U [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Wolf, Kurt Bernardo [Centro de Ciencias FIsicas, UNAM, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico)

    2004-05-28

    The finite q-oscillator is a model that obeys the dynamics of the harmonic oscillator, with the operators of position, momentum and Hamiltonian being functions of elements of the q-algebra su{sub q}(2). The spectrum of position in this discrete system, in a fixed representation j, consists of 2j + 1 'sensor'-points x{sub s} = 1/2 [2s]{sub q}, s element of {l_brace}-j, -j+1, ..., j{r_brace}, and similarly for the momentum observable. The spectrum of energies is finite and equally spaced, so the system supports coherent states. The wavefunctions involve dual q-Kravchuk polynomials, which are solutions to a finite-difference Schroedinger equation. Time evolution (times a phase) defines the fractional Fourier-q-Kravchuk transform. In the classical limit as q {yields} 1 we recover the finite oscillator Lie algebra, the N = 2j {yields} {infinity} limit returns the Macfarlane-Biedenharn q-oscillator and both limits contract the generators to the standard quantum-mechanical harmonic oscillator.

  20. Finite q-oscillator

    Science.gov (United States)

    Atakishiyev, Natig M.; Klimyk, Anatoliy U.; Wolf, Kurt Bernardo

    2004-05-01

    The finite q-oscillator is a model that obeys the dynamics of the harmonic oscillator, with the operators of position, momentum and Hamiltonian being functions of elements of the q-algebra suq(2). The spectrum of position in this discrete system, in a fixed representation j, consists of 2j + 1 'sensor'-points x_s={\\case12}[2s]_q, s\\in\\{-j,-j+1,\\ldots,j\\} , and similarly for the momentum observable. The spectrum of energies is finite and equally spaced, so the system supports coherent states. The wavefunctions involve dual q-Kravchuk polynomials, which are solutions to a finite-difference Schrödinger equation. Time evolution (times a phase) defines the fractional Fourier-q-Kravchuk transform. In the classical limit as q rarr 1 we recover the finite oscillator Lie algebra, the N = 2j rarr infin limit returns the Macfarlane-Biedenharn q-oscillator and both limits contract the generators to the standard quantum-mechanical harmonic oscillator.

  1. Oscillate boiling from microheaters

    Science.gov (United States)

    Li, Fenfang; Gonzalez-Avila, S. Roberto; Nguyen, Dang Minh; Ohl, Claus-Dieter

    2017-01-01

    We report about an intriguing boiling regime occurring for small heaters embedded on the boundary in subcooled water. The microheater is realized by focusing a continuous wave laser beam to about 10 μ m in diameter onto a 165-nm-thick layer of gold, which is submerged in water. After an initial vaporous explosion a single bubble oscillates continuously and repeatedly at several 100 kHz albeit with constant laser power input. The microbubble's oscillations are accompanied with bubble pinch-off, leading to a stream of gaseous bubbles in the subcooled water. The self-driven bubble oscillation is explained with a thermally kicked oscillator caused by surface attachment and by the nonspherical collapses. Additionally, Marangoni stresses induce a recirculating streaming flow which transports cold liquid towards the microheater, reducing diffusion of heat along the substrate and therefore stabilizing the phenomenon to many million cycles. We speculate that this oscillate boiling regime may overcome the heat transfer thresholds observed during the nucleate boiling crisis and offers a new pathway for heat transfer under microgravity conditions.

  2. Oscillations following periodic reinforcement.

    Science.gov (United States)

    Monteiro, Tiago; Machado, Armando

    2009-06-01

    Three experiments examined behavior in extinction following periodic reinforcement. During the first phase of Experiment 1, four groups of pigeons were exposed to fixed interval (FI 16s or FI 48s) or variable interval (VI 16s or VI 48s) reinforcement schedules. Next, during the second phase, each session started with reinforcement trials and ended with an extinction segment. Experiment 2 was similar except that the extinction segment was considerably longer. Experiment 3 replaced the FI schedules with a peak procedure, with FI trials interspersed with non-food peak interval (PI) trials that were four times longer. One group of pigeons was exposed to FI 20s PI 80s trials, and another to FI 40s PI 160s trials. Results showed that, during the extinction segment, most pigeons trained with FI schedules, but not with VI schedules, displayed pause-peck oscillations with a period close to, but slightly greater than the FI parameter. These oscillations did not start immediately after the onset of extinction. Comparing the oscillations from Experiments 1 and 2 suggested that the alternation of reconditioning and re-extinction increases the reliability and earlier onset of the oscillations. In Experiment 3 the pigeons exhibited well-defined pause-peck cycles since the onset of extinction. These cycles had periods close to twice the value of the FI and lasted for long intervals of time. We discuss some hypotheses concerning the processes underlying behavioral oscillations following periodic reinforcement.

  3. Oscillations in stellar superflares

    CERN Document Server

    Balona, L A; Kosovichev, A; Nakariakov, V M; Pugh, C E; Van Doorsselaere, T

    2015-01-01

    Two different mechanisms may act to induce quasi-periodic pulsations (QPP) in whole-disk observations of stellar flares. One mechanism may be magneto-hydromagnetic (MHD) forces and other processes acting on flare loops as seen in the Sun. The other mechanism may be forced local acoustic oscillations due to the high-energy particle impulse generated by the flare (known as `sunquakes' in the Sun). We analyze short-cadence Kepler data of 257 flares in 75 stars to search for QPP in the flare decay branch or post-flare oscillations which may be attributed to either of these two mechanisms. About 18 percent of stellar flares show a distinct bump in the flare decay branch of unknown origin. The bump does not seem to be a highly-damped global oscillation because the periods of the bumps derived from wavelet analysis do not correlate with any stellar parameter. We detected damped oscillations covering several cycles (QPP), in seven flares on five stars. The periods of these oscillations also do not correlate with any ...

  4. Arbitrary Spin Galilean Oscillator

    CERN Document Server

    Hagen, C R

    2014-01-01

    The so-called Dirac oscillator was proposed as a modification of the free Dirac equation which reproduces many of the properties of the simple harmonic oscillator but accompanied by a strong spin-orbit coupling term. It has yet to be extended successfully to the arbitrary spin S case primarily because of the unwieldiness of general spin Lorentz invariant wave equations. It is shown here using the formalism of totally symmetric multispinors that the Dirac oscillator can, however, be made to accommodate spin by incorporating it into the framework of Galilean relativity. This is done explicitly for spin zero and spin one as special cases of the arbitrary spin result. For the general case it is shown that the coefficient of the spin-orbit term has a 1/S behavior by techniques which are virtually identical to those employed in the derivation of the g-factor carried out over four decades ago.

  5. Oscillations in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Hoeye, Gudrun Kristine

    1999-07-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  6. Nonlinear harmonic oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Calogero, F [Dipartimento di Fisica, Universita di Roma ' La Sapienza' (Italy); Inozemtsev, V I [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2002-12-06

    The existence is noted of assemblies of an arbitrary number of complex oscillators, or equivalently, of an arbitrary even number of real oscillators, characterized by Newtonian equations of motion ('acceleration equal force') with one-body velocity-dependent linear forces and many-body velocity-independent cubic forces, all the nonsingular solutions of which are isochronous (completely periodic with the same period). As for the singular solutions, as usual they emerge, in the context of the initial-value problem, from a closed domain in phase space having lower dimensionality.

  7. Prediction of resonant oscillation

    DEFF Research Database (Denmark)

    2010-01-01

    The invention relates to methods for prediction of parametric rolling of vessels. The methods are based on frequency domain and time domain information in order do set up a detector able to trigger an alarm when parametric roll is likely to occur. The methods use measurements of e.g. pitch and roll...... oscillations and compare the measured oscillations using FFT analysis of signal correlations, variance analysis of signals and other comparisons. As an example, the presence of a growing peak around a frequency that doubles the roll natural frequency indicates the possibility that parametric roll is going...

  8. Friedel oscillations in graphene

    DEFF Research Database (Denmark)

    Lawlor, J. A.; Power, S. R.; Ferreira, M.S.

    2013-01-01

    Symmetry breaking perturbations in an electronically conducting medium are known to produce Friedel oscillations in various physical quantities of an otherwise pristine material. Here we show in a mathematically transparent fashion that Friedel oscillations in graphene have a strong sublattice...... asymmetry. As a result, the presence of impurities and/or defects may impact the distinct graphene sublattices very differently. Furthermore, such an asymmetry can be used to explain the recent observations that nitrogen atoms and dimers are not randomly distributed in graphene but prefer to occupy one...

  9. Solar-neutrino oscillations

    Science.gov (United States)

    Krauss, L.; Wilczek, F.

    1985-01-01

    The theory of oscillations of solar neutrinos is developed as it applies to the electron-recoil spectrum in neutrino-electron scattering. The spectral information obtained by such measurements (as opposed to counting total event rates) is crucial for allowing observation of neutrino oscillations for masses down to 500 neV. In this regard, the effects of different masses and mixing angles, as well as such subtleties as thermal and pressure broadening, finite solar-core size, and variable indices of refraction are investigated.

  10. Oscillation Baselining and Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    2017-03-27

    PNNL developed a new tool for oscillation analysis and baselining. This tool has been developed under a new DOE Grid Modernization Laboratory Consortium (GMLC) Project (GM0072 - “Suite of open-source applications and models for advanced synchrophasor analysis”) and it is based on the open platform for PMU analysis. The Oscillation Baselining and Analysis Tool (OBAT) performs the oscillation analysis and identifies modes of oscillations (frequency, damping, energy, and shape). The tool also does oscillation event baselining (fining correlation between oscillations characteristics and system operating conditions).

  11. 主动配电网背景下无功电压控制方法研究综述%Research Overview on Reactive Power Voltage Control Method Under Background of Active Distribution Network

    Institute of Scientific and Technical Information of China (English)

    倪鹏; 孙富荣

    2016-01-01

    介绍了主动配电网(ADN)背景下分布式电源(DG)接入对配电网电压分布和电压稳定性影响,从电网结构优化调压措施、电网设备的调压措施、电力系统无功优化调度调压措施等方面阐述了ADN无功电压控制方法。基于当前研究现状,总结了现有关于ADN无功电压控制研究存在的不足,并指出了在未来亟待解决的几个问题。%Introduction was made to the impacts of distributed generation (DG) access under background of active distribution network (ADN) on the voltage distribution of DG and voltage stability. This paper expounded on the ADN reactive power voltage control method from the aspects of pressure regulating measures of power network structure optimization, power network equipment, optimal reactive power dispatch of power system and so on. Based on the current research status, this paper summarized the shortcomings existing in the research on ADN reactive power voltage control and pointed out several problems which are much-needed to solve in the future.

  12. Graded Voltage Control Strategy for Clustering Wind Farms Based on Doubly-fed Induction Generators%集群双馈风电场的分次调压控制

    Institute of Scientific and Technical Information of China (English)

    陈惠粉; 张毅威; 闵勇; 乔颖; 鲁宗相

    2013-01-01

    The characteristics of clustering wind farms are strongly coupled between reactive power and voltage of wind farms and poor communication reliability.Based on these characteristics, this paper proposes a graded voltage control strategy.In the control strategy, doubly-fed induction generators (DFIGs) are main reactive power resources because of their high reliable reactive power generation ability and capacitors/static var compensators (SVCs) are auxiliary reactive power resources.This makes the strategy independent of high speed and high reliability communication between DFIGs and wind farm automatic voltage control (AVC) system.According to the grid operation condition, the PQ curve of DFIG is calculated previously.Based on the pre-setting PQ curve, the reactive power output of DFIG is adjusted automatically to eliminate voltage fluctuation caused by change of active power output.Only when the grid operation condition changes significantly, the PQ curve need to be updated, that means the PQ curve need not be calculated in real time.When the voltage control aim is not achieved or the updating of PQ curve does not finish, capacitors/SVCs are then used to control voltage, which is called the secondary voltage control.Simulations on a real clustering wind farms in northern China is carried out.The results show that the probability of wind generators' cascading disconnection from power grid is reduced effectively with the proposed graded voltage control strategy.Communication failures between DFIGs and wind farm AVC system have no influences on control effect.%基于集群风电场间无功电压耦合较强、通信条件较差的特点,提出以双馈风电机组为主、电容器/静止无功补偿器(SVC)为辅,不过分依赖风电机组与风电场自动电压控制系统间通信的集群双馈风电场分次调压控制策略.事先根据电网运行状况计算得到不需实时更新的双馈风电机组的PQ曲线,同步补偿无功功率以应对有功出

  13. Oscillators and operational amplifiers

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2005-01-01

    A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation...

  14. [Oscillating physiotherapy for secretolysis].

    Science.gov (United States)

    Brückner, U

    2008-03-01

    Assisted coughing and mechanical cough aids compensate for the weak cough flow in patients with neuromuscular diseases (NMD). In cases with preserved respiratory muscles also breathing techniques and special devices, e. g., flutter or acapella can be used for secretion mobilisation during infections of the airways. These means are summarised as oscillating physiotherapy. Their mechanisms are believed to depend on separation of the mucus from the bronchial wall by vibration, thus facilitating mucus transport from the peripheral to the central airways. In mucoviscidosis and chronic obstructive pulmonary disease their application is established, but there is a paucity of data regarding the commitment in patients with neuromuscular diseases. The effective adoption of simple oscillation physiotherapeutic interventions demands usually a sufficient force of the respiratory muscles--exceptions are the application of the percussionaire (intrapulmonary percussive ventilator, IPV) or high frequency chest wall oscillation (HFCWO). In daily practice there is evidence that patients with weak respiratory muscles are overstrained with the use of these physiotherapeutic means, or get exhausted. A general recommendation for the adoption of simple oscillating physiotherapeutic interventions cannot be made in patients with NMDs. Perhaps in the future devices such as IPV or HFCWO will prove to be more effective in NMD patients.

  15. A simple violin oscillator

    Science.gov (United States)

    Jones, R. T.

    1976-01-01

    For acoustic tests the violin is driven laterally at the bridge by a small speaker of the type commonly found in pocket transistor radios. An audio oscillator excites the tone which is picked up by a sound level meter. Gross patterns of vibration modes are obtained by the Chladni method.

  16. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Hansen, Lars Kai; Parnas, Josef;

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...

  17. Neutrino oscillation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, L. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-11-01

    Neutrino oscillation experiments ({nu}{sub {mu}}{yields}{nu}{sub e} and {nu}{sub {mu}}{yields}{nu}{sub {tau}}) currently being performed at accelerators are reviewed. Future plans for short and long base-line experiments are summarized. (author) 10 figs., 2 tabs., 29 refs.

  18. Multiphoton coherent population oscillation

    CERN Document Server

    Sharypov, A V

    2014-01-01

    We study the bichromatic driving of a two-level system which displays long-lived coherent population oscillations (CPO). We show that under certain conditions, multiphoton parametric interaction leads to the appearance of CPO resonances at the subharmonic frequencies. In addition, in the region of the CPO resonances, there is strong parametric interaction between the weak sideband components of the electromagnetic field.

  19. From excitability to oscillations

    DEFF Research Database (Denmark)

    Postnov, D. E.; Neganova, A. Y.; Jacobsen, J. C. B.;

    2013-01-01

    One consequence of cell-to-cell communication is the appearance of synchronized behavior, where many cells cooperate to generate new dynamical patterns. We present a simple functional model of vasomotion based on the concept of a two-mode oscillator with dual interactions: via relatively slow...

  20. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.;

    2007-01-01

    to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  1. Neutrino Velocity and Neutrino Oscillations

    CERN Document Server

    Minakata, H

    2012-01-01

    We study distances of propagation and the group velocities of the muon neutrinos in the presence of mixing and oscillations assuming that Lorentz invariance holds. Oscillations lead to distortion of the $\

  2. Microwave transistor oscillator frequency tripling

    OpenAIRE

    B. A. Kotserzhynskyi

    2010-01-01

    The frequency tripler state of the art is consided. The oscillator-frequency tripler design is now at the state of scientific research. Microwave companies release the devices of the such structure: oscillator, buffer, amplifier-tripler.

  3. Microwave transistor oscillator frequency tripling

    Directory of Open Access Journals (Sweden)

    B. A. Kotserzhynskyi

    2010-01-01

    Full Text Available The frequency tripler state of the art is consided. The oscillator-frequency tripler design is now at the state of scientific research. Microwave companies release the devices of the such structure: oscillator, buffer, amplifier-tripler.

  4. Design of a Dual-Band VCO Using a Current-Source Switching Topology%基于电流源开关技术的双频VCO设计

    Institute of Scientific and Technical Information of China (English)

    田巧玉; 汪道辉

    2016-01-01

    基于0.18-μm CMOS工艺,采用电流源开关技术设计实现了一种双频压控振荡器(VCO).低频带和高频带振荡信号分别采用Colpitts模式和交叉耦合对(CCP)模式实现,不同于传统的采用谐振回路开关技术的双频VCO,所提出的VCO合成了Colpitts模块和CCP模块,避免了谐振回路额外的损耗,降低了电路功耗.设计实现的VCO芯片面积为0.97×0.81 mm2,测试结果表明当VCO工作于Colpitts模式下时,功耗为7.2 mW,在5.4 GHz振荡频率下,相位噪声为-118.1 dBc/Hz;工作于CCP模式下时,功耗为9.1 mW,在20.4 GHz振荡频率下,相位噪声为-106.1 dBc/Hz.

  5. A Constant Energy-Per-Cycle Ring Oscillator Over a Wide Frequency Range for Wireless Sensor Nodes.

    Science.gov (United States)

    Lee, Inhee; Sylvester, Dennis; Blaauw, David

    2016-03-01

    This paper presents an energy-efficient oscillator for wireless sensor nodes (WSNs). It avoids short-circuit current by minimizing the time spent in the input voltage range from Vthn to [Vdd - |Vthp|]. A current-feeding scheme with gate voltage control enables the oscillator to operate over a wide frequency range. A test chip is fabricated in a 0.18 μm CMOS process. The measurements show that the proposed oscillator achieves a constant energy-per-cycle (EpC) of 0.8 pJ/cycle over the 21-60 MHz frequency range and is more efficient than a conventional current-starved ring oscillator (CSRO) below 300 kHz at 1.8 V supply voltage. As an application example, the proposed oscillator is implemented in a switched-capacitor DC-DC converter. The converter is 11%-56% more efficient for load power values ranging from 583 pW to 2.9 nW than a converter using a conventional CSRO.

  6. Neutrino Oscillations with Nil Mass

    Science.gov (United States)

    Floyd, Edward R.

    2016-09-01

    An alternative neutrino oscillation process is presented as a counterexample for which the neutrino may have nil mass consistent with the standard model. The process is developed in a quantum trajectories representation of quantum mechanics, which has a Hamilton-Jacobi foundation. This process has no need for mass differences between mass eigenstates. Flavor oscillations and ν ,bar{ν } oscillations are examined.

  7. Resurgence of oscillation in coupled oscillators under delayed cyclic interaction

    Science.gov (United States)

    Bera, Bidesh K.; Majhi, Soumen; Ghosh, Dibakar

    2017-07-01

    This paper investigates the emergence of amplitude death and revival of oscillations from the suppression states in a system of coupled dynamical units interacting through delayed cyclic mode. In order to resurrect the oscillation from amplitude death state, we introduce asymmetry and feedback parameter in the cyclic coupling forms as a result of which the death region shrinks due to higher asymmetry and lower feedback parameter values for coupled oscillatory systems. Some analytical conditions are derived for amplitude death and revival of oscillations in two coupled limit cycle oscillators and corresponding numerical simulations confirm the obtained theoretical results. We also report that the death state and revival of oscillations from quenched state are possible in the network of identical coupled oscillators. The proposed mechanism has also been examined using chaotic Lorenz oscillator.

  8. Stable local oscillator module.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2007-11-01

    This report gives a description of the development of a Stable Local Oscillator (StaLO) multi-chip module (MCM). It is a follow-on report to SAND2006-6414, Stable Local Oscillator Microcircuit. The StaLO accepts a 100MHz input signal and produces output signals at 1.2, 3.3, and 3.6 GHz. The circuit is built as a multi-chip module (MCM), since it makes use of integrated circuit technologies in silicon and lithium niobate as well as discrete passive components. This report describes the development of an MCM-based version of the complete StaLO, fabricated on an alumina thick film hybrid substrate.

  9. Entanglement in neutrino oscillations

    Energy Technology Data Exchange (ETDEWEB)

    Blasone, M.; Dell' Anno, F.; De Siena, S.; Illuminati, F. [Universita degli Studi di Salerno Via Ponte don Melillon, Dipt. di Matematica e Informatica, Fisciano SA (Italy); INFN Sezione di Napoli, Gruppo collegato di Salerno - Baronissi SA (Italy); Dell' Anno, F.; De Siena, S.; Illuminati, F. [CNR-INFM Coherentia - Napoli (Italy); Blasone, M. [ISI Foundation for Scientific Interchange, Torino (Italy)

    2009-03-15

    Flavor oscillations in elementary particle physics are related to multimode entanglement of single-particle states. We show that mode entanglement can be expressed in terms of flavor transition probabilities, and therefore that single-particle entangled states acquire a precise operational characterization in the context of particle mixing. We treat in detail the physically relevant cases of two- and three-flavor neutrino oscillations, including the effective measure of CP violation. We discuss experimental schemes for the transfer of the quantum information encoded in single-neutrino states to spatially delocalized two-flavor charged-lepton states, thus showing, at least in principle, that single-particle entangled states of neutrino mixing are legitimate physical resources for quantum information tasks. (authors)

  10. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  11. Physics of Neutrino Oscillation

    CERN Document Server

    Mondal, Spandan

    2015-01-01

    The Standard Model of particle physics describes neutrinos as massless, chargeless elementary particles that come in three different flavours. However, recent experiments indicate that neutrinos not only have mass, but also have multiple mass eigenstates that are not identical to the flavour states, thereby indicating mixing. As an evidence of mixing, neutrinos have been observed to change from one flavour to another during their propagation, a phenomenon called neutrino oscillation. We have studied the reasons and derived the probabilities of neutrino flavour change, both in vacuum and in matter. We have also studied the parameters affecting this probability. We have discussed the special case of two-neutrino oscillations. Lastly, we have discussed some basic properties of neutrinos that are reflected in the previous derivations and highlighted a few relevant open problems. To begin with, we have also studied the relevant topics in introductory High Energy Physics and Quantum Mechanics to familiarize with th...

  12. Neutrino Masses and Oscillations

    CERN Document Server

    CERN. Geneva. Audiovisual Unit; Treille, Daniel

    2002-01-01

    This course will not cover its subject in the customary way. The emphasis will be on the simple theoretical concepts (helicity, handedness, chirality, Majorana masses) which are obscure in most of the literature, and on the quantum mechanics of oscillations, that ALL books get wrong. Which, hopefully, will not deter me from discussing some of the most interesting results from the labs and from the cosmos.

  13. Oscillations in the bispectrum

    CERN Document Server

    Meerburg, P Daniel

    2010-01-01

    There exist several models of inflation that produce primordial bispectra that contain a large number of oscillations. In this paper we discuss these models, and aim at finding a method of detecting such bispectra in the data. We explain how the recently proposed method of mode expansion of bispectra might be able to reconstruct these spectra from separable basis functions. Extracting these basis functions from the data might then lead to observational constraints on these models.

  14. Polychromatic optical Bloch oscillations.

    Science.gov (United States)

    Longhi, Stefano

    2009-07-15

    Bloch oscillations (BOs) of polychromatic beams in circularly curved optical waveguide arrays are smeared out owing to the dependence of the BO spatial period on the wavelength. Here it is shown that restoring of the self-imaging property of the array and approximate BOs over relatively broad spectral ranges can be achieved by the insertion of suitable lumped phase slips uniformly applied across the array.

  15. Nonlinear Oscillators in Space Physics

    Science.gov (United States)

    Lester,Daniel; Thronson, Harley

    2011-01-01

    We discuss dynamical systems that produce an oscillation without an external time dependent source. Numerical results are presented for nonlinear oscillators in the Em1h's atmosphere, foremost the quasi-biennial oscillation (QBOl. These fluid dynamical oscillators, like the solar dynamo, have in common that one of the variables in a governing equation is strongly nonlinear and that the nonlinearity, to first order, has particular form. of 3rd or odd power. It is shown that this form of nonlinearity can produce the fundamental li'equency of the internal oscillation. which has a period that is favored by the dynamical condition of the fluid. The fundamental frequency maintains the oscillation, with no energy input to the system at that particular frequency. Nonlinearities of 2nd or even power could not maintain the oscillation.

  16. Temperature sensitive oscillator

    Science.gov (United States)

    Kleinberg, L. L. (Inventor)

    1986-01-01

    An oscillator circuit for sensing and indicating temperature by changing oscillator frequency with temperature comprises a programmable operational amplifier which is operated on the roll-off portion of its gain versus frequency curve and has its output directly connected to the inverting input to place the amplifier in a follower configuration. Its output is also connected to the non-inverting input by a capacitor with a crystal or other tuned circuit also being connected to the non-inverting input. A resistor is connected to the program input of the amplifier to produce a given set current at a given temperature, the set current varying with temperature. As the set current changes, the gain-bandwidth of the amplifier changes and, in turn, the reflected capacitance across the crystal changes, thereby providing the desired change in oscillator frequency by pulling the crystal. There is no requirement that a crystal employed with this circuit display either a linear frequency change with temperature or a substantial frequency change with temperature.

  17. Threshold switching and electrical self-oscillation in niobium oxide films

    Science.gov (United States)

    Liu, Xinjun; Li, Shuai; Nandi, Sanjoy Kumar; Venkatachalam, Dinesh Kumar; Elliman, Robert Glen

    2016-09-01

    Electrical self-sustained oscillations have been observed in a broad range of two-terminal systems and are of interest as possible building blocks for bio-inspired neuromorphic computing. In this work, we experimentally explore voltage-controlled oscillations in NbOx devices with a particular focus on understanding how the frequency and waveform are influenced by circuit parameters. We also introduce a finite element model of the device based on a Joule-heating induced insulator-metal transition. The electroformed device structure is represented by a cylindrical conductive channel (filament) comprised of NbO/NbO2 zones and surrounded by an Nb2O5-x matrix. The model is shown to reproduce the current-controlled negative differential resistance observed in measured current-voltage curves, and is combined with circuit elements to simulate the waveforms and dynamics of an isolated Pearson-Anson oscillator. Such modeling is shown to provide considerable insight into the relationship between the material response and device and circuit characteristics.

  18. Hierarchical-partitioned Voltage Control Under Security Safeguard System of Microgrid%微电网安全防御体系下电压分层分区控制

    Institute of Scientific and Technical Information of China (English)

    张玮亚; 李永丽; 孙广宇; 靳伟; 李小叶

    2015-01-01

    现有微电网安全防御体系缺少保护和紧急控制与微电网局部和全局电压控制的配合方案,无法保障故障后的电压质量。针对接入大量分布式电源(DG)、含多公共连接点(PCC)的公共微电网,提出了一种微电网安全防御体系下电压分层分区控制(HPVC)方案,HPVC 基于电压控制型DG接收PCC区域控制器信号主动参与电压控制,以微电网保护动作完成故障切除时刻为界分两阶段完成:第1阶段控制区域孤岛形成前各分区 PCC 电压不超越相电压安全带,降低 DG 脱网几率;第2阶段实施具有相电压偏差反时限特性的自适应电压恢复控制,实现区域孤岛形成后各分区电压的平滑恢复,辅助微电网完成分区自愈及重新并网,解决了电压控制的“点—面”矛盾,实现了微电网安全防御体系下电压质量的全局综合优化。最后在Simulink中建立IEEE P1547.4典型微电网拓扑,仿真结果验证了该方案的有效性和可行性。%The existing security safeguard system of microgrid lacks complementary schemes between protection and emergency control and local and global voltage control,thus unable to meet the user demand for post-fault voltage quality.A voltage-controlled distributed generator (DG) based hierarchical-partitioned voltage control (HPVC) strategy for multiple DGs is proposed to solve the voltage quality problems for microgrid with single point of common coupling (PCC) and multiple PCCs. The strategy is implemented in two stages at the boundary of fault clearing.The first stage is aimed to control the phase voltage not exceeding the voltage security region before island-mode is formed,which requires low DG capacity and reduces the offline probability;the second stage introduces the inverse-time phase-voltage deviation control to recover the voltage after island-mode is developed,achieving zonal self-healing and restoring grid-connected mode,thereby solving the

  19. Acquisition of a Nd-Yag Pumped MOPO (Master Oscillator/Power Oscillator) Optical Parametric Oscillator

    Science.gov (United States)

    1997-09-30

    SEP 1997 2. REPORT TYPE 3. DATES COVERED 00-00-1997 to 00-00-1997 4. TITLE AND SUBTITLE Acquisition of a Nd-Yag Pumped MOPO (Master Oscillator...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 ACQUISITION OF A ND-YAG PUMPED MOPO (MASTER OSCILLATOR / POWER OSCILLATOR) OPTICAL...instrument is configured in a master oscillator/power oscillator configuration, hence the designation MOPO . The MOPO will be used in conjunction

  20. Development of GaAs Gunn Diodes and Their Applications to Frequency Modulated Continuous Wave Radar

    Science.gov (United States)

    Choi, Seok-Gyu; Han, Min; Baek, Yong-Hyun; Ko, Dong-Sik; Baek, Tae-Jong; Lee, Sang-Jin; Kim, Jin-Ho; Lee, Seong-Dae; Kim, Mi-Ra; Chae, Yeon-Sik; Kathalingam, Adaikalam; Rhee, Jin-Koo

    2010-11-01

    In this work, we have designed and fabricated the GaAs Gunn diodes for a 94 GHz waveguide voltage controlled oscillator (VCO) which is one of the important parts in a frequency modulated continuous wave (FMCW) radar application. For fabrication of the high power GaAs Gunn diodes, we adopted a graded gap injector which enhances the output power and conversion efficiency by effectively removing the dead-zone. We have measured RF characteristics of the fabricated GaAs Gunn diodes. The operating current, oscillation frequency, and output power of the fabricated GaAs Gunn diodes are presented as a function of the anode diameters. The operating current increases with anode diameters, whereas the oscillation frequency decreases. The higher oscillation frequency was obtained from 60 µm anode diameters of the fabricated Gunn GaAs diodes and higher power was obtained from 68 µm. Also, for application of the 94 GHz FMCW radar system, we have fabricated the 94 GHz waveguide VCO. From the fabricated GaAs Gunn diodes of anode diameter of 60 µm, we have obtained the improved VCO performance.