Analysis and Design of a 1.8-GHz CMOS LC Quadrature VCO
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...
A Power-Efficient LC Quadrature VCO for RFID, Zigbee and Bluetooth Standards
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.
LC Quadrature Generation in Integrated Circuits
Christensen, Kåre Tais
2001-01-01
Today quadrature signals for IQ demodulation are provided through RC polyphase networks, quadrature oscillators or double frequency VCOs. This paper presents a new method for generating quadrature signals in integrated circuits using only inductors and capacitors. This LC quadrature generation me...
A wideband LC-VCO with small VCO gain variation and adaptive power control
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.
A dual-band quadrature VCO with gain proportional to oscillation frequency
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.
A low-phase-noise wide-band CMOS quadrature VCO for multi-standard RF front-ends
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....
Analytical design of a 0.5V 5GHz CMOS LC-VCO
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.
A new resonant circuit for 2.45 GHz LC VCO with linear frequency tuning
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...
Behavioral modeling of rf VCO circuit with MEMS LC resonator
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).
A 2GHz, 17% tuning range quadrature CMOS VCO with high figure–of–merit and 0.6° phase error
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°....
A 2.3GHz LC-tank CMOS VCO with optimal phase noise performance
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...
A 12 GHz low-jitter LC-VCO PLL in 130 nm CMOS
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.
An Ultra Wideband VHF CMOS LC VCO%超宽频带VHF频段CMOS LC VCO
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.
The Optimum Design Methodology of Low-Phase-Noise LC-VCO Using Multiple-Divide Technique
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.
カレントソースを共有化したCMOS Quadrature-coupled LC-VCOの解析
春岡, 正起; 洞木, 吉博; 松岡, 俊匡; 谷口, 研二; ハルオカ, マサキ; ウツロギ, ヨシヒロ; マツオカ, トシマサ; タニグチ, ケンジ; Haruoka, Masaki; Utsurogi, Yoshihiro; Matsuoka, Toshimasa; Taniguchi, Kenji
2004-01-01
二つのLC-VCOを結合させたQuadrature-coupled LC-VCO(QVCO)のIQ出力の精度についてシミュレーション解析を行った．QVCOを構成する二つのVCOのカレントソース用トランジスタを共有化することにより，精度が向上することを確認した．
47.8 GHz InPHBT quadrature VCO with 22% tuning range
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...
A New Low-Power CMOS Quadrature VCO with Current Reused Structure
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.
A Low Phase Noise Fully Monolithic 6 GHz Differential Coupled NMOS LC-VCO
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.
Bottom-series coupled quadrature VCO using the inductive gate voltage boosting technique
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.
A 2.4 GHz high-linearity low-phase-noise CMOS LC-VCO based on capacitance compensation
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}.
A wide-band low phase noise LC-tuned VCO with constant KVCO/ωosc for LTE PLL
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.
A wideband 0.13μm CMOS LC-VCO for IMT-advanced and UWB applications
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.
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.
A CMOS LC VCO with 3.2～6.1GHz Tuning Range%频率覆盖3.2～6.1 GHz的CMOS LC VCO
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.
On the amplitude and phase errors of quadrature LC-tank CMOS oscillators
Mazzanti, Andrea; Svelto, Francesco; Andreani, Pietro
2006-01-01
An analytic approach for the estimation of the phase and amplitude imbalances caused by component mismatches and parasitic magnetic fields in two popular quadrature LC oscillators is presented. Very simple and closed-form equations are derived, proving that, although the two topologies share...
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.
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.
一种双带宽UHF主从耦合式LC VCO%UHF Master-Slave Coupled LC VCO with Two Bandwidthes
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.
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.
LC VCO相位噪声解析模型的分析%Analysis of Phase Noise Analytical Model in LC VCO
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.
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.
一种高性能宽带LC VCO的设计%Design of a High Performance LC VCO for Broadband Application
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.
A time-variant analysis of the 1/f^(2) phase noise in CMOS parallel LC-Tank quadrature oscillators
Andreani, Pietro
2006-01-01
This paper presents a study of 1/f2 phase noise in quadrature oscillators built by connecting two differential LC-tank oscillators in a parallel fashion. The analysis clearly demonstrates the necessity of adopting a time-variant theory of phase noise, where a more simplistic, time......-invariant approach fails to explain numerical simulation results even at the qualitative level. Two topologies of 5-GHz parallel quadrature oscillators are considered, and compact but nevertheless highly general, closed-form formulas are derived for the phase noise caused by the losses in the LC...
Single-Stage Low-Power Quadrature RF Receiver Front-End: The LMV Cell
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...
Low Voltage Low Power Quadrature LC Oscillator Based on Back-gate Superharmonic Capacitive Coupling
Ma, Minglin; Li, Zhijun
2013-09-01
This work introduces a new low voltage low power superharmonic capacitive coupling quadrature LC oscillator (QLCO) made by coupling two identical cross-connected LC oscillators without tail transistor. In each of the core oscillators, the back-gate nodes of the cross-coupled NMOS pair and PMOS pair, acting as common mode nodes, have been connected directly. Then the core oscillators are coupled together via capacitive coupling of the PMOS common mode node in one of the core oscillators to the NMOS common mode node in the other core oscillator, and vice versa. Only capacitors are used for coupling of the two core oscillators and therefore no extra noise sources are imposed on the circuit. Operation of the proposed QLCO was investigated with simulation using a commercial 0.18 µm RF CMOS technology: it shows a power dissipation of 5.2 mW from a 0.6 V supply voltage. Since the proposed core oscillator has Complementary NMOS and PMOS cross coupled pairs, and capacitive coupling method will not introduce extra phase noise, so this circuit can operate with a low phase noise as low as -126.8 dBc/Hz at 1 MHz offset from center oscillation frequency of 2.4 GHz, as confirmed with simulation.
A 5.4mW GPS CMOS quadrature front-end based on a single-stage LNA-mixer-VCO
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....
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
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.
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
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.
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
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 .
A new approach for probing the phase noise of LC-VCO%压控振荡器相位噪声的一种建模研究方法
胡晓莉; 李章全; 李萍
2010-01-01
电感电容压控振荡器(LC-VCO)是无线收发电路中的重要单元,它的频谱纯洁度将直接影响频率合成后的信号频谱,所以相位噪声是VCO的最重要的指标之一.提出了一种研究LC-VCO相位噪声的方法,使用VerilogA语言建立可控噪声和可控寄生电容的晶体管模型,通过用所建立的模型代替原有的spice晶体管模型来构成LC-VCO电路并进行仿真,能够对噪声和寄生电容进行开关控制,从而观察不同的噪声源以及不同的寄生特性对电路相位噪声的影响.使用该晶体管模型,仿真验证了噪声滤波理论中差分对管结电容对最优电感值选取的影响以及滤波电感对白噪声和闪烁噪声不同的抑制作用.
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
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.
Low-Power CMOS VCO with Dual-Band Local Oscillating Signal Outputs for 5/2.5-GHz WLAN Transceivers
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.
Design of LC VCO with Freguency within 2.2～5.5 GHz and Lower Phase Noise%一种2.2～5.5 G宽带低相位噪声LC VCO设计
谷华宝; 吴建辉
2009-01-01
论文基于BiCMOS工艺,采用了8个LC VCO并列的工作模式实现了2.2～5.5 GHz的带宽范围的LC VCO,每个LC VCO可以进行单独的调节.在LC VOC的核心电路中采用电阻代替电流镜方式以及在输出处增加了两个三极管限幅,以得到较低的相位噪声.在各个LC VCO的中心频率处其相位噪声优于-96 dBc@100 kHz.当电源电压为5 V时,各个LC VCO的工作电流为3.2 mA～4.2 mA.
Quadrature frequency generation for wideband wireless applications
Elbadry, Mohammad
2015-01-01
This book describes design techniques for wideband quadrature LO generation for software defined radio transceivers, with frequencies spanning 4GHz to around 80GHz. The authors discuss several techniques that can be used to reduce the cost and/or power consumption of one of the key components of the RF front-end, the quadrature local oscillator. The discussion includes simple and useful insights into quadrature VCOs, along with numerous examples of practical techniques. · Provides a thorough survey of quadrature LO generation; · Offers an intuitive explanation of the different quadrature VCO architectures, and categorization of these architectures based on the intuitive explanations; · Describes a new technique for simultaneous quadrature LO generation for channelized receivers; · Includes simple and detailed explanation of two new quadrature VCO techniques that improve phase-noise performance of QVCOs, while providing a large tuning rang...
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
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
Design of a Core-size-scalable Low Phase Noise LC VCO%一种核心尺寸可缩放的低相位噪声LC VCO设计
周雅
2016-01-01
基于TSMC 0.13μm互补金属氧化物半导体(CMOS)工艺,设计了一种用于多标准移动收发机的核心尺寸可缩放LC压控振荡器(VCO).理论分析表明,当核心电流较小时,较大尺寸的VCO具有较低的相位噪声,而当核心电流较大时,较小尺寸的VCO具有较低的相位噪声,因此,该文将VCO的核心尺寸设置成可随电流变化的缩放尺寸.最终芯片测试结果表明,在核心电流为4.2 mA,振荡频率5 GHz的情况下,VCO的相位噪声为-121.6 dBc/Hz@1 MHz;在核心电流为16 mA,振荡频率5 GHz的情况下,VCO的相位噪声为-128.5 dBc/Hz@1 MHz.
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)
Design And Investigation Of 65 Nm Rf Cmos Technology Lc-Vco’s
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.
Fully Integrated 1.7GHz, 188dBc/Hz FoM, 0.8V, 320uW LC-tank VCO and Frequency Divider
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...
A 0.18 {mu}m CMOS single-inductor single-stage quadrature frontend for GNSS receiver
Li Bing; Zhuang Yiqi; Han Yeqi; Xing Xiaoling; Li Zhenrong; Long Qiang, E-mail: waxmax@126.com [Key Laboratory of the Ministry of Education for Wide Bandgap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)
2011-09-15
This paper presents an improved merged architecture for a low-IF GNSS receiver frontend, where the bias current and functions are reused in a stacked quadrature LNA-mixer-VCO. Only a single spiral inductor is implemented for the LC resonator and an extra 1/2 frequency divider is added as the quadrature LO signal generator. The details of the design are presented. The gain plan and noise figure are discussed. The phase noise, quadrature accuracy and power consumption are improved. The test chip is fabricated though a 0.18 {mu}m RF CMOS process. The measured noise figure is 5.4 dB on average, with a gain of 43 dB and a IIP3 of -39 dBm. The measured phase noise is better than -105 dBc/Hz at 1 MHz offset. The total power consumption is 19.8 mW with a 1.8 V supply. The experimental results satisfy the requirements for GNSS applications. (semiconductor integrated circuits)
A Robust 43-GHz VCO in CMOS for OC-768 SONET Applications
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
Correction for quadrature errors
Netterstrøm, A.; Christensen, Erik Lintz
1994-01-01
In high bandwidth radar systems it is necessary to use quadrature devices to convert the signal to/from baseband. Practical problems make it difficult to implement a perfect quadrature system. Channel imbalance and quadrature phase errors in the transmitter and the receiver result in error signal...
Design And Investigation Of 65 Nm Rf Cmos Technology Lc-Vco’s
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...
Multichannel VCO needs only one reference
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).
Enhancement of VCO Linearity and Phase Noise by Implementing Frequency Locked Loop
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...
A 65 nm CMOS high efficiency 50 GHz VCO with regard to the coupling effect of inductors
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).
Chebfun and numerical quadrature
Hale, Nicholas
2012-07-24
Chebfun is a Matlab-based software system that overloads Matlab\\'s discrete operations for vectors and matrices to analogous continuous operations for functions and operators. We begin by describing Chebfun\\'s fast capabilities for Clenshaw-Curtis and also Gauss-Legendre, -Jacobi, -Hermite, and -Laguerre quadrature, based on algorithms of Waldvogel and Glaser, Liu and Rokhlin. Then we consider how such methods can be applied to quadrature problems including 2D integrals over rectangles, fractional derivatives and integrals, functions defined on unbounded intervals, and the fast computation of weights for barycentric interpolation. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.
IC design of low power, wide tuning range VCO in 90 nm CMOS technology
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.
A 1.0 V differential VCO in 0.13μm CMOS technology*
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.
A fully integrated VCO with a wide tuning range for DVB-H
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.
Advanced differential quadrature methods
Zong, Zhi
2009-01-01
Modern Tools to Perform Numerical DifferentiationThe original direct differential quadrature (DQ) method has been known to fail for problems with strong nonlinearity and material discontinuity as well as for problems involving singularity, irregularity, and multiple scales. But now researchers in applied mathematics, computational mechanics, and engineering have developed a range of innovative DQ-based methods to overcome these shortcomings. Advanced Differential Quadrature Methods explores new DQ methods and uses these methods to solve problems beyond the capabilities of the direct DQ method.After a basic introduction to the direct DQ method, the book presents a number of DQ methods, including complex DQ, triangular DQ, multi-scale DQ, variable order DQ, multi-domain DQ, and localized DQ. It also provides a mathematical compendium that summarizes Gauss elimination, the Runge-Kutta method, complex analysis, and more. The final chapter contains three codes written in the FORTRAN language, enabling readers to q...
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.
Field analysis and CAD millimeter wave VCO
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.
Digital quadrature phase detection
Smith, J.A.; Johnson, J.A.
1992-05-26
A system for detecting the phase of a frequency or phase modulated signal that includes digital quadrature sampling of the frequency or phase modulated signal at two times that are one quarter of a cycle of a reference signal apart, determination of the arctangent of the ratio of a first sampling of the frequency or phase modulated signal to the second sampling of the frequency or phase modulated signal, and a determination of quadrant in which the phase determination is increased by 2[pi] when the quadrant changes from the first quadrant to the fourth quadrant and decreased by 2[pi] when the quadrant changes from the fourth quadrant to the first quadrant whereby the absolute phase of the frequency or phase modulated signal can be determined using an arbitrary reference convention. 6 figs.
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.
A 3.16-7 GHz transformer-based dual-band CMOS VCO
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).
Design of the Low Phase Noise VCO%低相位噪声VCO的设计
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.
VCO PLL Frequency Synthesizers for Spacecraft Transponders
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.
A Low Phase Noise CMOS Quadrature Voltage Control Oscillator Using Clock Gated Technique
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
Ring VCO Design with Variable Capacitance XNOR Delay Cell
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.
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...
Analysis of VCO based noise shaping ADCs linearized by PWM modulation
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...
A varactor tuned low-cost 24 GHz harmonic VCO
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.
Refinements of some new efficient quadrature rules
Qayyum, A.; Shoaib, M.; Faye, I.; Kashif, A. R.
2016-11-01
In the field of Engineering and Applied Mathematical Sciences, minimizing approximation error is very important task and therefore quadrature rules are investigated regularly. In this paper, using some standard results of theoretical inequalities, e.g. Ostrowski type inequality, some new efficient quadrature rules are introduced for n-times differentiable mappings. These quadrature rules are expected to give better results comparing to the conventional quadrature rules.
AN EXTREMAL APPROACH TO BIRKHOFF QUADRATURE FORMULAS
Ying-guang Shi
2001-01-01
As we know, a solution of an extremal problem with Hermite interpolation constraints is a system of nodes of corresponding Gaussian Hermite quadrature formula (the so-called Jacobi approach). But this conclusion is violated for a Birkhoff quadrature formula. In this paper an extremal problem with Birkhoff interpolation constraints is discussed, from which a large class of Birkhoff quadrature formulas may be derived.
Length Scales in Bayesian Automatic Adaptive Quadrature
Adam Gh.
2016-01-01
Full Text Available Two conceptual developments in the Bayesian automatic adaptive quadrature approach to the numerical solution of one-dimensional Riemann integrals [Gh. Adam, S. Adam, Springer LNCS 7125, 1–16 (2012] are reported. First, it is shown that the numerical quadrature which avoids the overcomputing and minimizes the hidden floating point loss of precision asks for the consideration of three classes of integration domain lengths endowed with specific quadrature sums: microscopic (trapezoidal rule, mesoscopic (Simpson rule, and macroscopic (quadrature sums of high algebraic degrees of precision. Second, sensitive diagnostic tools for the Bayesian inference on macroscopic ranges, coming from the use of Clenshaw-Curtis quadrature, are derived.
Quadrature formulas for Fourier coefficients
Bojanov, Borislav
2009-09-01
We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.
A-189 dBc/Hz FoMT Wide Tuning Range VCO Using Q-Factor Enhancement Technique
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.
A Jitter Less VCO Model in PLL for EMTP Simulation
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.
A 23 GHz low power VCO in SiGe BiCMOS technology
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.
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...
A 90nm, Low Power VCO with Reduced KVCO and Sub−band Spacing Variation
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 ...
Error Analysis of Quadrature Rules. Classroom Notes
Glaister, P.
2004-01-01
Approaches to the determination of the error in numerical quadrature rules are discussed and compared. This article considers the problem of the determination of errors in numerical quadrature rules, taking Simpson's rule as the principal example. It suggests an approach based on truncation error analysis of numerical schemes for differential…
Automatic quadrature control and measuring system
Hamlet, J. F.
1973-01-01
Quadrature is separated from amplified signal by use of phase detector, with phase shifter providing appropriate reference. Output of phase detector is further amplified and filtered by dc amplifier. Output of dc amplifier provides signal to neutralize quadrature component of transducer signal.
Numerical Quadrature of Periodic Singular Integral Equations
Krenk, Steen
1978-01-01
This paper presents quadrature formulae for the numerical integration of a singular integral equation with Hilbert kernel. The formulae are based on trigonometric interpolation. By integration a quadrature formula for an integral with a logarithmic singularity is obtained. Finally...... it is demonstrated how a singular integral equation with infinite support can be solved by use of the preceding formulae....
Proven procedures guide cavity VCO design
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.
Design of a CMOS multi-mode GNSS receiver VCO
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.
Advanced on-chip divider for monolithic microwave VCO's
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.
Advanced on-chip divider for monolithic microwave VCO's
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.
Angular quadratures for improved transport computations
Abu-Shumays, I.K.
1999-07-22
This paper introduces new octant-range, composite-type Gauss and mid-point rule angular quadrature formulas for neutron and photon transport computations. A generalization to octant-range quadratures is also introduced in order to allow for discontinuities at material interfaces for two- and three-dimensional transport problems which can be modeled with 60-degree triangular or hexagonal mesh subdivisions in the x-y plane.
Compensation of temperature frequency pushing in microwave resonator-meters on the basis VCO
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.
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...
An X-Band low-power and low-phase-noise VCO using bondwire inductor
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...
A 220-1100 MHz low phase-noise frequency synthesizer with wide-band VCO and selectable I/Q divider
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.
差分LC VCO的设计方法%Design Method in Optimization Differential LC VCO
满家汉; 赵坤
2005-01-01
通过分析振荡器的两种典型相位噪声模型,给出了振荡器相位噪声与电路参数的关系.在此基础上,提出了优化VCO相位噪声的设计方法:设计高Q值电感;调整尾电流的大小;调整nMOS管和pMOS管的尺寸.文章最后给出了一个2.4GHz全集成VCO的设计,仿真结果表明在2.4GHz时VCO的相位噪声为-120.4dBc/Hz@ 600 kHz,证明该方法对于VCO的设计具有较好的指导作用.
Spacecraft redesign to reduce microphonic response of a VCO component
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.
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.
Theory of the quadrature elliptic birdcage coil.
Leifer, M C
1997-11-01
This paper presents the theory of the quadrature birdcage coil wound on an elliptic cylindrical former. A conformal transformation of the ellipse to a circular geometry is used to derive the optimal sampling of the continuous surface current distribution to produce uniform magnetic fields within an elliptic cylinder. The analysis is rigorous for ellipses of any aspect ratio and shows how to produce quadrature operation of the elliptic birdcage with a conventional hybrid combiner. Insight gained from the transformation is also used to analyze field homogeneity, find the optimal RF shield shape, and specify component values to produce the correct current distribution in practice. Measurements and images from a 16-leg elliptic birdcage coil at both low and high frequencies show good quadrature performance, homogeneity, and sensitivity.
Low phase noise GaAs HBT VCO in Ka-band
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.
An X-Band low-power and low-phase-noise VCO using bondwire inductor
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.
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
Summation Paths in Clenshaw-Curtis Quadrature
Adam S.
2016-01-01
Full Text Available Two topics concerning the use of Clenshaw-Curtis quadrature within the Bayesian automatic adaptive quadrature approach to the numerical solution of Riemann integrals are considered. First, it is found that the efficient floating point computation of the coefficients of the Chebyshev series expansion of the integrand is to be done within a mathematical structure consisting of the union of coefficient families ordered into complete binary trees. Second, the scrutiny of the decay rates of the involved even and odd rank Chebyshev expansion coefficients with the increase of their rank labels enables the definition of Bayesian decision paths for the advancement to the numerical output.
Numerical Quadratures for Hadamard Hypersingular Integrals
无
2006-01-01
In this paper, we develop Gaussian quadrature formulas for the Hadamard finite part integrals. In our formulas, the classical orthogonal polynomials such as Legendre and Chebyshev polynomials are used to approximate the density function f(x) so that the Gaussian quadrature formulas have degree n - 1. The error estimates of the formulas are obtained. It is found from the numerical examples that the convergence rate and the accuracy of the approximation results are satisfactory. Moreover, the rate and the accuracy can be improved by choosing appropriate weight functions.
Composite Gauss-Legendre Quadrature with Error Control
Prentice, J. S. C.
2011-01-01
We describe composite Gauss-Legendre quadrature for determining definite integrals, including a means of controlling the approximation error. We compare the form and performance of the algorithm with standard Newton-Cotes quadrature. (Contains 1 table.)
Composite Gauss-Legendre Quadrature with Error Control
Prentice, J. S. C.
2011-01-01
We describe composite Gauss-Legendre quadrature for determining definite integrals, including a means of controlling the approximation error. We compare the form and performance of the algorithm with standard Newton-Cotes quadrature. (Contains 1 table.)
ON QUADRATURE FORMULAE FOR SINGULAR INTEGRALS OF ARBITRARY ORDER
杜金元
2004-01-01
Some quadrature formulae for the numerical evaluation of singular integrals of arbitrary order are established and both the estimate of remainder and the convergence of each quadrature formula derived here are also given.
Quadrature representation of finite element variational forms
Ølgaard, Kristian Breum; Wells, Garth N.
2012-01-01
This chapter addresses the conventional run-time quadrature approach for the numerical integration of local element tensors associated with finite element variational forms, and in particular automated optimizations that can be performed to reduce the number of floating point operations...
Integrated source of broadband quadrature squeezed light
Hoff, Ulrich Busk; Nielsen, Bo Melholt; Andersen, Ulrik Lund
2015-01-01
An integrated silicon nitride resonator is proposed as an ultracompact source of bright single-mode quadrature squeezed light at 850 nm. Optical properties of the device are investigated and tailored through numerical simulations, with particular attention paid to loss associated with interfacing...
Asymptotic Properties of Unbounded Quadrature Domains in the Plane
Karp, Lavi
2013-01-01
We prove that if $\\Omega$ is a simply connected quadrature domain for a distribution with compact support and the infinity point belongs the boundary, then the boundary has an asymptotic curve that is either a straight line or a parabola or an infinite ray. In other words, unbounded quadrature domains in the plane are perturbations of null quadrature domains.
Radial Basis Function Based Quadrature over Smooth Surfaces
2016-03-24
Function Interpolation . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.3 Weight calculations...methods: product Gaussian quadrature and finite element integration. The product Gaussian quadrature uses Gauss-Legendre nodes and quadrature weights ...with Gaussian Radial Basis Functions ,” SIAM J. Sci. Comput., vol. 33, pp. 869–892, 2011. 10. B. Fornberg and J. Zuev, “The Runge Phenomenon and
The magnetic map at the V/Co interface
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.
324GHz CMOS VCO Using Linear Superimposition Technique
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.
One way Doppler Extractor. Volume 2: Digital VCO technique
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.
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.
A K-Band Push-Push VCO MMIC using embedded frequency doubling mechanism
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...
Automatic quadrature control and measuring system. [using optical coupling circuitry
Hamlet, J. F. (Inventor)
1974-01-01
A quadrature component cancellation and measuring system comprising a detection system for detecting the quadrature component from a primary signal, including reference circuitry to define the phase of the quadrature component for detection is described. A Raysistor optical coupling control device connects an output from the detection system to a circuit driven by a signal based upon the primary signal. Combining circuitry connects the primary signal and the circuit controlled by the Raysistor device to subtract quadrature components. A known current through the optically sensitive element produces a signal defining the magnitude of the quadrature component.
Twelfth degree spline with application to quadrature.
Mohammed, P O; Hamasalh, F K
2016-01-01
In this paper existence and uniqueness of twelfth degree spline is proved with application to quadrature. This formula is in the class of splines of degree 12 and continuity order [Formula: see text] that matches the derivatives up to order 6 at the knots of a uniform partition. Some mistakes in the literature are pointed out and corrected. Numerical examples are given to illustrate the applicability and efficiency of the new method.
Association of VO2 and VCO2 rate variability with serum glucose, insulin, and glucose intolerance.
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.
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
Efficient Quadrature Operator Using Dual-Perspectives-Fusion Probabilistic Weights
Ashok Sahai
2009-08-01
Full Text Available A new quadrature formula has been proposed which uses weight functions derived using a probabilistic approach, and a rather-ingenious 'Fusion' of two dual perspectives. Unlike the complicatedly structured quadrature formulae of Gauss,Hermite and others of similar type, the proposed quadrature formula only needs the values of integrand at user-defined equidistant points in the interval of integration. The weights are functions of the impugned variable in the integrand, and are not mere constants. The quadrature formula has been compared empirically with the simple classical method of numerical integration using the well-known "Bernstein Operator". The percentage absolute relative errors for the proposed quadrature formula and that with the "Bernstein Operator" have been computed for certain selected functions and with different number of node points in the interval of integration. It has been observed that the proposed quadrature formula produces significantly better results.
GALERKIN MESHLESS METHODS BASED ON PARTITION OF UNITY QUADRATURE
ZENG Qing-hong; LU De-tang
2005-01-01
Numerical quadrature is an important ingredient of Galerkin meshless methods. A new numerical quadrature technique, partition of unity quadrature (PUQ),for Galerkin meshless methods was presented. The technique is based on finite covering and partition of unity. There is no need to decompose the physical domain into small cell. It possesses remarkable integration accuracy. Using Element-free Galerkin methods as example, Galerkin meshless methods based on PUQ were studied in detail. Meshing is always not required in the procedure of constitution of approximate function or numerical quadrature, so Galerkin meshless methods based on PUQ are "truly"meshless methods.
Integrated source of broadband quadrature squeezed light
Hoff, Ulrich Busk; Nielsen, Bo Melholt; Andersen, Ulrik Lund
2015-01-01
An integrated silicon nitride resonator is proposed as an ultracompact source of bright single-mode quadrature squeezed light at 850 nm. Optical properties of the device are investigated and tailored through numerical simulations, with particular attention paid to loss associated with interfacing...... squeezing spectrum for intra-cavity pump self-phase modulation. Subject to standard material loss and detection efficiencies, we find that the device holds promises for generating substantial quantum noise squeezing over a bandwidth exceeding 1 GHz. In the low-propagation loss regime, approximately -6 d...
Blood cholesterol levels of hypercholesterolemic rat (Rattus norvegicus after VCO treatment
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.
Kadar kolesterol darah tikus putih (Rattus norvegicus hiperkolesterolemik setelah perlakuan VCO
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.
A low-power current self-adjusted VCO using a bottom PMOS current source
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.
PENGARUH KONSENTRASI XANTHAN GUM TERHADAP STABILITAS FISIK KRIM VIRGIN COCONUT OIL (VCO
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
Nonlinear analysis of a cross-coupled quadrature harmonic oscillator
Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens;
2005-01-01
The dynamic equations governing the cross-coupled quadrature harmonic oscillator are derived assuming quasi-sinusoidal operation. This allows for an investigation of the previously reported tradeoff between close-to-carrier phase noise and quadrature precision. The results explain how nonlinearit...
Quadrature Formula of Singular Integral Based on Rational Interpolation
无
2002-01-01
We construct a quadrature formula of the singular integral with the Chebyshev weight of the second kind by using Lagrange interpolation based on the rational system {1/(x-a1),1/(x-a2),...}, and both the remainder and convergence of the quadrature formula established here are discussed. Our results extend some classical ones.
Single-quadrature continuous-variable quantum key distribution
Gehring, Tobias; Jacobsen, Christian Scheffmann; Andersen, Ulrik Lund
2016-01-01
Most continuous-variable quantum key distribution schemes are based on the Gaussian modulation of coherent states followed by continuous quadrature detection using homodyne detectors. In all previous schemes, the Gaussian modulation has been carried out in conjugate quadratures thus requiring two...... commercialization of continuous-variable quantum key distribution, provided that the low noise requirement can be achieved....
Quadrature measurements of a bright squeezed state via sideband swapping
Schneider, J.; Glockl, O.; Leuchs, G.
2009-01-01
The measurement of an arbitrary quadrature of a bright quantum state of light is a commonly requested action in many quantum information protocols, but it is experimentally challenging with previously proposed schemes. We suggest that the quadrature be measured at a specific sideband frequency...
Quadrature rules and distribution of points on manifolds
Brandolini, Luca; Colzani, Leonardo; Gigante, Giacomo; Seri, Raffaello; Travaglini, Giancarlo
2010-01-01
We study the error in quadrature rules on a compact manifold. As in the Koksma-Hlawka inequality, we consider a discrepancy of the sampling points and a generalized variation of the function. In particular, we give sharp quantitative estimates for quadrature rules of functions in Sobolev classes.
Nonlinear Analysis of a Cross-Coupled Quadrature Harmonic Oscillator
Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens;
2004-01-01
We derive the dynamic equations governing the cross-coupled quadrature oscillator leading to an expression for the trade-off between signal quadrature and close-in phase noise. The theory shows that nonlinearity in the coupling transconductance results in AM-PM noise close to the carrier, which...
1-GHz CMOS VCO design for wireless application using MEMS technology
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.
High accuracy digital aging monitor based on PLL-VCO circuit
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%.
Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator
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...
A bulk-controlled ring-VCO with 1/f-noise reduction for frequency ΔΣ modulator
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...
Power flow control using quadrature boosters
Sadanandan, Sandeep N.
A power system that can be controlled within security constraints would be an advantage to power planners and real-time operators. Controlling flows can lessen reliability issues such as thermal limit violations, power stability problems, and/or voltage stability conditions. Control of flows can also mitigate market issues by reducing congestion on some lines and rerouting power to less loaded lines or onto preferable paths. In the traditional control of power flows, phase shifters are often used. More advanced methods include using Flexible AC Transmission System (FACTS) Controllers. Some examples include Thyristor Controlled Series Capacitors, Synchronous Series Static Compensators, and Unified Power Flow Controllers. Quadrature Boosters (QBs) have similar structures to phase-shifters, but allow for higher voltage magnitude during real power flow control. In comparison with other FACTS controllers QBs are not as complex and not as expensive. The present study proposes to use QBs to control power flows on a power system. With the inclusion of QBs, real power flows can be controlled to desired scheduled values. In this thesis, the linearized power flow equations used for power flow analysis were modified for the control problem. This included modifying the Jacobian matrix, the power error vector, and calculating the voltage injected by the quadrature booster for the scheduled real power flow. Two scenarios were examined using the proposed power flow control method. First, the power flow in a line in a 5-bus system was modified with a QB using the method developed in this thesis. Simulation was carried out using Matlab. Second, the method was applied to a 30-bus system and then to a 118-bus system using several QBs. In all the cases, the calculated values of the QB voltages led to desired power flows in the designated line.
Linearity of Bulk-Controlled Inverter Ring VCO in Weak and Strong Inversion
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...
Multilevel quadrature of elliptic PDEs with log-normal diffusion
Harbrecht, Helmut
2015-01-07
We apply multilevel quadrature methods for the moment computation of the solution of elliptic PDEs with lognormally distributed diffusion coefficients. The computation of the moments is a difficult task since they appear as high dimensional Bochner integrals over an unbounded domain. Each function evaluation corresponds to a deterministic elliptic boundary value problem which can be solved by finite elements on an appropriate level of refinement. The complexity is thus given by the number of quadrature points times the complexity for a single elliptic PDE solve. The multilevel idea is to reduce this complexity by combining quadrature methods with different accuracies with several spatial discretization levels in a sparse grid like fashion.
A Robust 43 GHz VCO in Standard CMOS for OC-768 SONET Applications
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
Wide tuning-range CMOS VCO based on a tunable active inductor
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.
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.
Researching on quadrature conversion structures for an UWB demonstrative receiver
Zhu Canyan; Wang Yiming; Yang Huibao; Liu Jiasheng
2006-01-01
Some structures of digital quadrature AD conversion for software-defined radio (SDR) systems are studied. Their performances and affections on the SDR systems are also analyzed. Two generalized quadrature AD schemes are proposed. In one of them, the AD sampling speed can be reduced by 2 times; and in the other both the output data rate of every channel and AD sampling speed can be lowered by paralleling the digital quadrature filtering structure. These structures can be also easily implemented into modules, and the polyphase filters can be flexibly realized by VHDL language based one chip of FPGA. To assess the proposed schemes, their applications to a particular ultra wideband (UWB) demonstrative receiver system are introduced. Some experimental results are also given. It is shown that the generalized quadrature AD structures are reliable and feasible for its module design, and performances are improved obviously for its better performance to price ratio.
Two integrator loop quadrature oscillators: A review
Soliman, Ahmed M.
2012-01-01
A review of the two integrator loop oscillator circuits providing two quadrature sinusoidal output voltages is given. All the circuits considered employ the minimum number of capacitors namely two except one circuit which uses three capacitors. The circuits considered are classified to four different classes. The first class includes floating capacitors and floating resistors and the active building blocks realizing these circuits are the Op Amp or the OTRA. The second class employs grounded capacitors and includes floating resistors and the active building blocks realizing these circuits are the DCVC or the unity gain cells or the CFOA. The third class employs grounded capacitors and grounded resistors and the active building blocks realizing these circuits are the CCII. The fourth class employs grounded capacitors and no resistors and the active building blocks realizing these circuits are the TA. Transformation methods showing the generation of different classes from each other is given in details and this is one of the main objectives of this paper. PMID:25685396
Two integrator loop quadrature oscillators: A review
Ahmed M. Soliman
2013-01-01
Full Text Available A review of the two integrator loop oscillator circuits providing two quadrature sinusoidal output voltages is given. All the circuits considered employ the minimum number of capacitors namely two except one circuit which uses three capacitors. The circuits considered are classified to four different classes. The first class includes floating capacitors and floating resistors and the active building blocks realizing these circuits are the Op Amp or the OTRA. The second class employs grounded capacitors and includes floating resistors and the active building blocks realizing these circuits are the DCVC or the unity gain cells or the CFOA. The third class employs grounded capacitors and grounded resistors and the active building blocks realizing these circuits are the CCII. The fourth class employs grounded capacitors and no resistors and the active building blocks realizing these circuits are the TA. Transformation methods showing the generation of different classes from each other is given in details and this is one of the main objectives of this paper.
Electronically Tunable Quadrature Oscillator Using Translinear Conveyors and Grounded Capacitors
Sudhanshu Maheshwari
2003-01-01
A new electronically tunable current-mode sinusoidal oscillator with three quadrature outputs is presented. The proposed circuit employs three translinear conveyors and two grounded capacitors to realize three quadrature outputs with independent frequency control. The circuit requires no resistors and the frequency of the oscillator can be varied over a wide range by external current control. RSPICE simulation results using the bipolar implementation of translinear conveyors are given to s...
Density Tracking by Quadrature for Stochastic Differential Equations
Bhat, Harish S.; Madushani, R. W. M. A.
2016-01-01
We develop and analyze a method, density tracking by quadrature (DTQ), to compute the probability density function of the solution of a stochastic differential equation. The derivation of the method begins with the discretization in time of the stochastic differential equation, resulting in a discrete-time Markov chain with continuous state space. At each time step, the DTQ method applies quadrature to solve the Chapman-Kolmogorov equation for this Markov chain. In this paper, we focus on a p...
Exact and Approximate Quadratures for Curvature Tensor Estimation
Langer, Torsten; Belyaev, Alexander; Seidel, Hans-Peter; Greiner, Günther; Hornegger, Joachim; Niemann, Heinrich; Stamminger, Marc
2005-01-01
Accurate estimations of geometric properties of a surface from its discrete approximation are important for many computer graphics and geometric modeling applications. In this paper, we derive exact quadrature formulae for mean curvature, Gaussian curvature, and the Taubin integral representation of the curvature tensor. The exact quadratures are then used to obtain reliable estimates of the curvature tensor of a smooth surface approximated by a dense triangle me...
A COMPACT QUADRATURE FEEDING CIRCUIT FOR CIRCULARLY POLARIZED ANTENNA
Dong Yuliang; Tian Buning; Tang Song
2002-01-01
A novel compact quadrature feeding circuit for a circularly polarized antenna is described. The equivalent circuit method in microwave network theory is used and the conventional directional coupler is converted to a new quadrature feeding circuit. This feeding circuit has the same characteristics as the conventional directional coupler but its size is only about one fourth of that of the latter. The formulas for designing the feeding circuit are given. The optimized results obtained by using the software ENSEMBLE are also reported.
Noncritical quadrature squeezing through spontaneous polarization symmetry breaking
Garcia-Ferrer, Ferran V; de Valcárcel, Germán J; Roldán, Eugenio
2010-01-01
We discuss the possibility of generating noncritical quadrature squeezing by spontaneous polarization symmetry breaking. We consider first type-II frequency-degenerate optical parametric oscillators, but discard them for a number of reasons. Then we propose a four-wave mixing cavity in which the polarization of the output mode is always linear but has an arbitrary orientation. We show that in such a cavity complete noise suppression in a quadrature of the output field occurs, irrespective of the parameter values.
Quadrature mixture LO suppression via DSW DAC noise dither
Dubbert, Dale F.; Dudley, Peter A.
2007-08-21
A Quadrature Error Corrected Digital Waveform Synthesizer (QECDWS) employs frequency dependent phase error corrections to, in effect, pre-distort the phase characteristic of the chirp to compensate for the frequency dependent phase nonlinearity of the RF and microwave subsystem. In addition, the QECDWS can employ frequency dependent correction vectors to the quadrature amplitude and phase of the synthesized output. The quadrature corrections cancel the radars' quadrature upconverter (mixer) errors to null the unwanted spectral image. A result is the direct generation of an RF waveform, which has a theoretical chirp bandwidth equal to the QECDWS clock frequency (1 to 1.2 GHz) with the high Spurious Free Dynamic Range (SFDR) necessary for high dynamic range radar systems such as SAR. To correct for the problematic upconverter local oscillator (LO) leakage, precision DC offsets can be applied over the chirped pulse using a pseudo-random noise dither. The present dither technique can effectively produce a quadrature DC bias which has the precision required to adequately suppress the LO leakage. A calibration technique can be employed to calculate both the quadrature correction vectors and the LO-nulling DC offsets using the radar built-in test capability.
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...
A bulk-controlled ring-VCO with 1/f-noise reduction for frequency ΔΣ modulator
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...
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
Low-Voltage, Low-Power, and Wide-Tuning-Range Ring-VCO for Frequency ΔΣ Modulator
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...
Steady State Condition in the Measurement of VO2and VCO2by Indirect Calorimetry.
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.
A Wide Tuning-Range CMOS VCO with a Tunable Active Inductor
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.
Wide range fully integrated VCO with new cells-based varactor
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.
Design of Transmission Gate VCO and Dynamic PFD for Low Power CMOS PLL
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.
A low-power time-domain VCO-based ADC in 65 nm CMOS
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.
Formulation and stability of whitening VCO-in-water nano-cream.
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.
A low power CMOS VCO using inductive-biasing with high performance FoM
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).
VCO Production from Fresh Old Coconut Bunch by Circulating and Pumping Method
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.
VCO Production from Fresh Old Coconut Bunch by Circulating and Pumping Method
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.
Processing Methode Effect to Virgin Coconut Oil (VCO Quality After Storaging
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.
ADAPTIVE CALIBRATION OF I AND Q MISMATCH IN QUADRATURE RECEIVER
Yang Xuexian; Hou Zifeng; Zhang Qunying; Ning Yanqing
2002-01-01
The mismatch of in-phase and quadrature channels in quadrature receiver affects and constrains radar detection performance in coherent radar. It is necessary to keep the in-phase and quadrature branches symmetrical. In this letter, an adaptive method to detect imbalance parameters is derived by means of evaluating channel errors from the received signal sequences.No matter how the bias degree of the gain and phase errors in I/Q channels are, the proposed adaptive scheme can obtain good calibration results. And the required calculations are only a few multiplications and additions. No need of a special test signal, the introduced method is simple to implement and easy to operate.
Fast algorithms for Quadrature by Expansion I: Globally valid expansions
Rachh, Manas; Klöckner, Andreas; O'Neil, Michael
2017-09-01
The use of integral equation methods for the efficient numerical solution of PDE boundary value problems requires two main tools: quadrature rules for the evaluation of layer potential integral operators with singular kernels, and fast algorithms for solving the resulting dense linear systems. Classically, these tools were developed separately. In this work, we present a unified numerical scheme based on coupling Quadrature by Expansion, a recent quadrature method, to a customized Fast Multipole Method (FMM) for the Helmholtz equation in two dimensions. The method allows the evaluation of layer potentials in linear-time complexity, anywhere in space, with a uniform, user-chosen level of accuracy as a black-box computational method. Providing this capability requires geometric and algorithmic considerations beyond the needs of standard FMMs as well as careful consideration of the accuracy of multipole translations. We illustrate the speed and accuracy of our method with various numerical examples.
McGraw, R [Environmental Sciences Department, Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Leng, L; Zhu, W [Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY 11794-3600 (United States); Riemer, N [Atmospheric Sciences Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3070 (United States); West, M [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801-3070 (United States)], E-mail: rlm@bnl.gov
2008-07-15
The method of moments (MOM) is a statistically based alternative to sectional and modal methods for aerosol simulation. The MOM is highly efficient as the aerosol distribution is represented by its lower-order moments and only these, not the full distribution itself, are tracked during simulation. Quadrature is introduced to close the moment equations under very general growth laws and to compute aerosol physical and optical properties directly from moments. In this paper the quadrature method of moments (QMOM) is used in a bivariate test tracking of aerosol mixing state. Two aerosol populations, one enriched in soot and the other in sulfate, are allowed to interact through coagulation to form a generally-mixed third particle population. Quadratures of varying complexity (including two candidate schemes for use in climate models) are described and compared with benchmark results obtained by using particle-resolved simulation. Low-order quadratures are found to be highly accurate, and Gauss and Gauss-Radau quadratures appear to give nested lower and upper bounds, respectively, to aerosol mixing rate. These results suggest that the QMOM makes it feasible to represent the generallymixed states of aerosols and track their evolution in climate models.
A VCO Based on LTCC Technology%基于LTCC技术的VCO研制
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.
Bell's inequality for systems with quadrature phase coherence
Tan, S. M.; Holland, M. J.; Walls, D. F.
1990-07-01
We show that a violation of Bell's inequalities by quadrature phase measurements is not due to the interference of the two photons in a photon pair state. Rather the violation predicted by Grangier et al. for a parametric down-converter is due to the interference of the photon pair state with the vacuum. We propose new sources which violate the quadrature phase Bell's inequalities, including one which employs squeezed light and another which demonstrates the non-local properties of a single photon state.
Analytical Formulae for Two of A. H. Stroud's Quadrature Rules
Peterson, J W
2009-01-01
Analytical formulae for the points and weights of two fifth-order quadrature rules for C_3, the 3-cube, are given. The rules, originally formulated by A. H. Stroud in 1967, are discussed in greater detail in terms of both the setup of the basic equations and the method of obtaining their solutions analytically. The primary purpose of this paper is to better document what we feel is a particularly practical quadrature rule (e.g. in finite element calculations) and one for which we felt comprehensive information was scarce.
A fully integrated W-band push-push CMOS VCO with low phase noise and wide tuning range.
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.
16-QAM Field-Quadrature Decomposition using Polarization-Assisted Phase Sensitive Amplification
Kjøller, Niels-Kristian; Piels, Molly; Da Ros, Francesco
2016-01-01
Simultaneous I and Q extraction for 16-QAM is experimentally demonstrated through field-quadrature decomposition using a polarization-assisted phase sensitive amplifier. The quadrature components are successfully received and performance is evaluated through bit-error-ratio testing.......Simultaneous I and Q extraction for 16-QAM is experimentally demonstrated through field-quadrature decomposition using a polarization-assisted phase sensitive amplifier. The quadrature components are successfully received and performance is evaluated through bit-error-ratio testing....
From Lobatto Quadrature to the Euler Constant "e"
Khattri, Sanjay Kumar
2010-01-01
Based on the Lobatto quadrature, we develop several new closed form approximations to the mathematical constant "e." For validating effectiveness of our approximations, a comparison of our results to the existing approximations is also presented. Another objective of our work is to inspire students to formulate other better approximations by using…
Archimedes Quadrature of the Parabola: A Mechanical View
Oster, Thomas J.
2006-01-01
In his famous quadrature of the parabola, Archimedes found the area of the region bounded by a parabola and a chord. His method was to fill the region with infinitely many triangles each of whose area he could calculate. In his solution, he stated, without proof, three preliminary propositions about parabolas that were known in his time, but are…
Archimedes Quadrature of the Parabola: A Mechanical View
Oster, Thomas J.
2006-01-01
In his famous quadrature of the parabola, Archimedes found the area of the region bounded by a parabola and a chord. His method was to fill the region with infinitely many triangles each of whose area he could calculate. In his solution, he stated, without proof, three preliminary propositions about parabolas that were known in his time, but are…
Self-calibrating quadrature mixing front-end for SDR
De Witt, JJ
2008-01-01
Full Text Available A quadrature mixing front-end is well-suited toward software define radio (SDR) applications, due to its low complexity and the inherent flexibility that it affords the radio front-end. Its performance is, however, severely affected by gain...
Entropy of phase measurement quantum phase via quadrature measurement
My, R; My, Robert; Uni, Palacky
1995-01-01
The content of phase information of an arbitrary phase--sensitive measurement is evaluated using the maximum likelihood estimation. The phase distribution is characterized by the relative entropy--a nonlinear functional of input quantum state. As an explicit example the multiple measurement of quadrature operator is interpreted as quantum phase detection achieving the ultimate resolution predicted by the Fisher information.
Quantum correlations induced by multiple scattering of quadrature squeezed light
Lodahl, Peter
2006-01-01
Propagating quadrature squeezed light through a multiple scattering random medium is found to induce pronounced spatial quantum correlations that have no classical analogue. The correlations are revealed in the number of photons transported through the sample that can be measured from the intensity...
Hittite Microwave公司推出低噪声C波段MMIC VCO
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
Osteotomía tibial alta con placa VCO: Resultados a medio plazo
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...
A 6 GHz high power and low phase noise VCO using an InGaP/GaAs HBT
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.
Design of Ka band MMIC VCO%Ka波段单片压控振荡器的设计
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.
DESIGN AND PERFORMANCE ANALYSIS OF VCO FOR STANDARD GSM USING MEMS
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.
Virgin Coconut Oil (VCO Enriched with Zn as Immunostimulator for Vaginal Candidiasis Patient
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.
Design optimizations of phase noise, power consumption and frequency tuning for VCO
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.
Quadrature-based Lattice Boltzmann Model for Relativistic Flows
Blaga, Robert
2016-01-01
A quadrature-based finite-difference lattice Boltzmann model is developed that is suitable for simulating relativistic flows of massless particles. We briefly review the relativistc Boltzmann equation and present our model. The quadrature is constructed such that the stress-energy tensor is obtained as a second order moment of the distribution function. The results obtained with our model are presented for a particular instance of the Riemann problem (the Sod shock tube). We show that the model is able to accurately capture the behavior across the whole domain of relaxation times, from the hydrodynamic to the ballistic regime. The property of the model of being extendable to arbitrarily high orders is shown to be paramount for the recovery of the analytical result in the ballistic regime.
Orthogonal functions, discrete variable representation, and generalized gauss quadratures
Schneider, B. I.; Nygaard, Nicolai
2002-01-01
The numerical solution of most problems in theoretical chemistry involve either the use of a basis set expansion (spectral method) or a numerical grid. For many basis sets, there is an intimate connection between the spectral form and numerical quadrature. When this connection exists, the distinc......The numerical solution of most problems in theoretical chemistry involve either the use of a basis set expansion (spectral method) or a numerical grid. For many basis sets, there is an intimate connection between the spectral form and numerical quadrature. When this connection exists...... in the original representation. This has been exploited in bound-state, scattering, and time-dependent problems using the so-called, discrete variable representation (DVR). At the core of this approach is the mathematical three-term recursion relationship satisfied by the classical orthogonal functions...
Observation of Localized Multi-Spatial-Mode Quadrature Squeezing
C. S. Embrey
2015-07-01
Full Text Available Quantum states of light can improve imaging whenever the image quality and resolution are limited by the quantum noise of the illumination. In the case of a bright illumination, quantum enhancement is obtained for a light field composed of many squeezed transverse modes. A possible realization of such a multi-spatial-mode squeezed state is a field which contains a transverse plane in which the local electric field displays reduced quantum fluctuations at all locations, on any one quadrature. Using a traveling-wave amplifier, we have generated a multi-spatial-mode squeezed state and showed that it exhibits localized quadrature squeezing at any point of its transverse profile, in regions much smaller than its size. We observe 75 independently squeezed regions. The amplification relies on nondegenerate four-wave mixing in a hot vapor and produces a bichromatic squeezed state. The result confirms the potential of this technique for producing illumination suitable for practical quantum imaging.
Structural dynamic responses analysis applying differential quadrature method
PU Jun-ping; ZHENG Jian-jun
2006-01-01
Unconditionally stable higher-order accurate time step integration algorithms based on the differential quadrature method (DQM) for second-order initial value problems were applied and the quadrature rules of DQM, computing of the weighting coefficients and choices of sampling grid points were discussed. Some numerical examples dealing with the heat transfer problem, the second-order differential equation of imposed vibration of linear single-degree-of-freedom systems and double-degree-of-freedom systems, the nonlinear move differential equation and a beam forced by a changing load were computed,respectively. The results indicated that the algorithm can produce highly accurate solutions with minimal time consumption, and that the system total energy can remain conservative in the numerical computation.
Quadrature-dependent Bogoliubov transformations and multiphoton squeezed states
De Siena, S; Illuminati, F; Siena, Silvio De; Lisi, Antonio Di; Illuminati, Fabrizio
2001-01-01
We introduce a linear, canonical transformation of the fundamental single--mode field operators $a$ and $a^{\\dagger}$ that generalizes the linear Bogoliubov transformation familiar in the construction of the harmonic oscillator squeezed states. This generalization is obtained by adding to the linear transformation a nonlinear function of any of the fundamental quadrature operators $X_{1}$ and $X_{2}$, making the original Bogoliubov transformation quadrature--dependent. Remarkably, the conditions of canonicity do not impose any constraint on the form of the nonlinear function, and lead to a set of nontrivial algebraic relations between the $c$--number coefficients of the transformation. We examine in detail the structure and the properties of the new quantum states defined as eigenvectors of the transformed annihilation operator $b$. These eigenvectors define a class of multiphoton squeezed states. The structure of the uncertainty products and of the quasiprobability distributions in phase space shows that bes...
Orthogonal functions, discrete variable representation, and generalized gauss quadratures
Schneider, B. I.; Nygaard, Nicolai
2002-01-01
, the basis of the generalized weight functions. We review these ideas below and apply then to the generation of the points and weights of the Rys polynomials which have proven useful in the evaluation of multicenter integrals, using Gaussian basis sets in quantum chemistry. In contrast to some approaches....... This three-term recursion can be used to generate the orthogonal functions as well as to generate the points and weights of Gauss quadratures on the basis of these functions. For the classical orthogonal functions, the terms in the three-term recursion are known analytically. For more general weight...... functions, this is not the case. However, they may be computed in a stable numerical fashion, via the recursion. In essence, this is an application of the well-known Lanczos recursion approach. Once the recursion coefficients are known, it is possible to compute the points and weights of quadratures on...
DDCC-Based Quadrature Oscillator with Grounded Capacitors and Resistors
Montree Kumngern
2009-01-01
Full Text Available A new voltage-mode quadrature oscillator using two differential difference current conveyors (DDCCs, two grounded capacitors, and three grounded resistors is presented. The proposed oscillator provides the following advantages: the oscillation condition and oscillation frequency are orthogonally controlled; the oscillation frequency is controlled through a single grounded resistor; the use of only grounded capacitors and resistors makes the proposed circuit ideal for IC implementation; low passive and active sensitivities. Simulation results verifying the theoretical analysis are also included.
Quadrature Uncertainty and Information Entropy of Quantum Elliptical Vortex States
Banerji, Anindya; Panigrahi, Prasanta. K.; Singh, Ravindra Pratap; Chowdhury, Saurav; Bandyopadhyay, Abir
2012-01-01
We study the quadrature uncertainty of the quantum elliptical vortex state using the associated Wigner function. Deviations from the minimum uncertainty states were observed due to the absence of the Gaussian nature. In our study of the entropy, we noticed that with increasing vorticity, entropy increases for both the modes. We further observed that, there exists an optimum value of ellipticity which gives rise to maximum entanglement of the two modes of the quantum elliptical vortex states. ...
Electronically Tunable Current-Mode Quadrature Oscillator Using Single MCDTA
Y. Li
2010-12-01
Full Text Available This paper presents a modified current differencing transconductance amlpifier (MCDTA and the MCDTA based quadrature oscillator. The oscillator is current-mode and provides current output from high output impedance terminals. The circuit uses only one MCDTA and two grounded capacitors, and is easy to be integrated. Its oscillation frequency can be tuned electronically by tuning bias currents of MCDTA. Finally, frequency error is analyzed. The results of circuit simulations are in agreement with theory.
A Simple Current-Mode Quadrature Oscillator Using Single CDTA
D. Biolek
2008-12-01
Full Text Available This article presents a simple current-mode quadrature oscillator using a single Current Differencing Transconductance Amplifier (CDTA as the active element. The oscillation condition and oscillation frequency can be electronically controlled. The circuit structure is very simple, consisting of merely one CDTA, one resistor and two capacitors. The proposed circuit is suitable for IC architecture. The PSpice simulation and experimental results are shown, and the results agree well with the theoretical assumptions.
Quadrature two-dimensional correlation spectroscopy (Q-2DCOS)
Noda, Isao
2016-11-01
Quadrature 2D correlation spectroscopy (Q-2DCOS) is introduced. The technique incorporates the effect of the perturbation into the traditional 2DCOS analysis by building a multivariate model, merging the information of the perturbation variable and spectral responses. By employing factors which are 90° out of phase with each other, pertinent coincidental and sequential spectral intensity variations are adequately captured for the subsequent 2D correlation analysis. Almost complete replication of the original 2DCOS results based on such a simple rank 2 model of experimental spectra suggests that only the dominant spectral intensity variation patterns in combination with its quadrature counterpart seems to be utilized in 2DCOS analysis. Using the linear perturbation variable itself as the basis for generating the primary score vector is equivalent to the least squares fitting of a quadratic polynomial with spectral intensity variations. Q-2DCOS analysis may be displayed in terms of a graphical plot on a phase plane in the vector space, so that coincidental and sequential matching of the patterns of spectral intensity variations is represented simply by the phase angle difference between two vectors. Q-2DCOS analysis is closely related to other established ideas and practices in the 2D correlation spectroscopy field, such as dynamic 2D IR dichroism, PCA 2D, quadrature orthogonal signal correction (Q-OSC), and perturbation correlation moving window (PCMW) analyses.
Beyond pressureless gas dynamics : Quadrature-based velocity moment models
Chalons, Christophe; Massot, Marc
2010-01-01
Following the seminal work of F. Bouchut on zero pressure gas dynamics which has been extensively used for gas particle-flows, the present contribution investigates quadrature-based velocity moments models for kinetic equations in the framework of the infinite Knudsen number limit, that is, for dilute clouds of small particles where the collision or coalescence probability asymptotically approaches zero. Such models define a hierarchy based on the number of moments and associated quadrature nodes, the first level of which leads to pressureless gas dynamics. We focus in particular on the four moment model where the flux closure is provided by a two-node quadrature in the velocity phase space and provide the right framework for studying both smooth and singular solutions. The link with both the kinetic underlying equation as well as with zero pressure gas dynamics is provided and we define the notion of measure solutions as well as the mathematical structure of the resulting system of four PDEs. We exhibit a fa...
Testing the Empirical Shock Arrival Model using Quadrature Observations
Gopalswamy, N; Xie, H; Yashiro, S
2013-01-01
The empirical shock arrival (ESA) model was developed based on quadrature data from Helios (in-situ) and P-78 (remote-sensing) to predict the Sun-Earth travel time of coronal mass ejections (CMEs) [Gopalswamy et al. 2005a]. The ESA model requires earthward CME speed as input, which is not directly measurable from coronagraphs along the Sun-Earth line. The Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO) were in quadrature during 2010 - 2012, so the speeds of Earth-directed CMEs were observed with minimal projection effects. We identified a set of 20 full halo CMEs in the field of view of SOHO that were also observed in quadrature by STEREO. We used the earthward speed from STEREO measurements as input to the ESA model and compared the resulting travel times with the observed ones from L1 monitors. We find that the model predicts the CME travel time within about 7.3 hours, which is similar to the predictions by the ENLIL model. We also find that CME-CME and CME...
Differential quadrature time element method for structural dynamics
Yu-Feng Xing; Jing Guo
2012-01-01
An accurate and efficient differential quadrature time element method (DQTEM) is proposed for solving ordinary differential equations (ODEs),the numerical dissipation and dispersion of DQTEM is much smaller than that of the direct integration method of single/multi steps.Two methods of imposing initial conditions are given,which avoids the tediousness when derivative initial conditions are imposed,and the numerical comparisons indicate that the first method,in which the analog equations of initial displacements and velocities are used to directly replace the differential quadrature (DQ) analog equations of ODEs at the first and the last sampling points,respectively,is much more accurate than the second method,in which the DQ analog equations of initial conditions are used to directly replace the DQ analog equations of ODEs at the first two sampling points.On the contrary to the conventional step-by-step direct integration schemes,the solutions at all sampling points can be obtained simultaneously by DQTEM,and generally,one differential quadrature time element may be enough for the whole time domain.Extensive numerical comparisons validate the efficiency and accuracy of the proposed method.
Statistical Quadrature Evolution for Continuous-Variable Quantum Key Distribution
Gyongyosi, Laszlo; Imre, Sandor
2016-05-01
We propose a statistical quadrature evolution (SQE) method for multicarrier continuous-variable quantum key distribution (CVQKD). A multicarrier CVQKD protocol utilizes Gaussian subcarrier quantum continuous variables (CV) for information transmission. The SQE framework provides a minimal error estimate of the quadratures of the CV quantum states from the discrete, measured noisy subcarrier variables. We define a method for the statistical modeling and processing of noisy Gaussian subcarrier quadratures. We introduce the terms statistical secret key rate and statistical private classical information, which quantities are derived purely by the statistical functions of our method. We prove the secret key rate formulas for a multiple access multicarrier CVQKD. The framework can be established in an arbitrary CVQKD protocol and measurement setting, and are implementable by standard low-complexity statistical functions, which is particularly convenient for an experimental CVQKD scenario. This work was partially supported by the GOP-1.1.1-11-2012-0092 project sponsored by the EU and European Structural Fund, by the Hungarian Scientific Research Fund - OTKA K-112125, and by the COST Action MP1006.
An Integrated 5 GHz Wideband Quadrature Modem for OFDM Gbit/s Transmission in SiGe:C BiCMOS
Klaus Schmalz
2007-01-01
Full Text Available This paper presents a 5 GHz wideband I/Q modulator/demodulator for 650 MHz OFDM signal bandwidth, which is integrated with a 5 GHz phase locked loop for I/Q generation. The quadrature signals are derived from a 10 GHz CMOS VCO followed by a bipolar frequency divider. The phase noise at 1 MHz offset is −112 dBc/Hz for the modulator as well as for the demodulator. The chips were produced in a 0.25 μm SiGe BiCMOS technology. The signal-to-noise ratio (SNR of transmitted/received OFDM signal and the corresponding I/Q mismatch versus baseband frequency are given. The modulator achieves an SNR of 22–23 dB, and the demodulator realizes an SNR up to 22 dB. The modulator reaches a data rate of 2.16 Gbit/s using 64 QAM OFDM, and the demodulator realizes 1.92 Gbits/s.
Design of Frequency Doubling VCO for Bluetooth Transceiver%一种用于Bluetooth发接器的倍频式VCO
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.
A Novel S-band VCO Based on LTCC Technology%基于LTCC技术S波段VCO研制
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.
Design of Low Phase-Noise Integrated Broadband VCO%集成宽带VCO的低相噪设计
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.
Modeling VCO with Noise Using Verilog- AMS%基于Verilog-AMS的VCO噪声建模
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.
Explicit Gaussian quadrature rules for C^1 cubic splines with symmetrically stretched knot sequence
Ait-Haddou, Rachid
2015-06-19
We provide explicit expressions for quadrature rules on the space of C^1 cubic splines with non-uniform, symmetrically stretched knot sequences. The quadrature nodes and weights are derived via an explicit recursion that avoids an intervention of any numerical solver and the rule is optimal, that is, it requires minimal number of nodes. Numerical experiments validating the theoretical results and the error estimates of the quadrature rules are also presented.
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.
On some quadrature rules with Gregory end corrections
Bogusław Bożek
2009-01-01
Full Text Available How can one compute the sum of an infinite series \\(s := a_1 + a_2 + \\ldots\\? If the series converges fast, i.e., if the term \\(a_n\\ tends to \\(0\\ fast, then we can use the known bounds on this convergence to estimate the desired sum by a finite sum \\(a_1 + a_2 + \\ldots + a_n\\. However, the series often converges slowly. This is the case, e.g., for the series \\(a_n = n^{-t}\\ that defines the Riemann zeta-function. In such cases, to compute \\(s\\ with a reasonable accuracy, we need unrealistically large values \\(n\\, and thus, a large amount of computation. Usually, the \\(n\\-th term of the series can be obtained by applying a smooth function \\(f(x\\ to the value \\(n\\: \\(a_n = f(n\\. In such situations, we can get more accurate estimates if instead of using the upper bounds on the remainder infinite sum \\(R = f(n + 1 + f(n + 2 + \\ldots\\, we approximate this remainder by the corresponding integral \\(I\\ of \\(f(x\\ (from \\(x = n + 1\\ to infinity, and find good bounds on the difference \\(I - R\\. First, we derive sixth order quadrature formulas for functions whose 6th derivative is either always positive or always negative and then we use these quadrature formulas to get good bounds on \\(I - R\\, and thus good approximations for the sum \\(s\\ of the infinite series. Several examples (including the Riemann zeta-function show the efficiency of this new method. This paper continues the results from [W. Solak, Z. Szydełko, Quadrature rules with Gregory-Laplace end corrections, Journal of Computational and Applied Mathematics 36 (1991, 251–253] and [W. Solak, A remark on power series estimation via boundary corrections with parameter, Opuscula Mathematica 19 (1999, 75–80].
Triangular Differential Quadrature for Bending Analysis of Reissner Plates with Curved Boundaries
华永霞; 钟宏志
2003-01-01
The recently proposed concept of the triangular differential quadrature method (TDQM) is applied to the bending analysis of Reissner plates with various curvilinear geometries subjected to various combinations of boundary conditions. A unit isosceles right triangle is used as the standard triangle for all the derivatives expressed using the triangular differential quadrature rule. Geometric transformations are introduced using basis functions to determine the weighting coefficients for the triangular differential quadrature to map an arbitrary curvilinear triangle into the standard triangle. The triangular differential quadrature method provides good accuracy and rapid convergence relative to other available exact and numerical results.
Null quadrature domains and a free boundary problem for the Laplacian
Karp, Lavi
2010-01-01
Null quadrature domains are unbounded domains in $\\R^n$ ($n \\geq 2$) with external gravitational force zero in some generalized sense. In this paper we prove a quadratic growth estimate of the Schwarz potential of a null quadrature domain and conclude by a theorem of Caffarelli, Karp and Shahgolian that any null quadrature domain is the complement of a convex set with analytic boundary. Using this result we prove that a null quadrature domain with a non-zero upper Lebesgue density at infinity is half-space.
The best quadrature formula based on Hermite information for the class KW2[a,b
WANG; Xinghua; MI; Xiangjiang
2005-01-01
The best quadrature formula has been found in the following sense: for a function whose norm of the second derivative is bounded by a given constant and the best quadrature formula for the approximate evaluation of integration of that function can minimize the worst possible error if the values of the function and its derivative at certain nodes are known.The best interpolation formula used to get the quadrature formula above is also found.Moreover,we compare the best quadrature formula with the open compound corrected trapezoidal formula by theoretical analysis and stochastic experiments.
Gaussian quadrature rules for C 1 quintic splines with uniform knot vectors
Bartoň, Michael
2017-03-21
We provide explicit quadrature rules for spaces of C1C1 quintic splines with uniform knot sequences over finite domains. The quadrature nodes and weights are derived via an explicit recursion that avoids numerical solvers. Each rule is optimal, that is, requires the minimal number of nodes, for a given function space. For each of nn subintervals, generically, only two nodes are required which reduces the evaluation cost by 2/32/3 when compared to the classical Gaussian quadrature for polynomials over each knot span. Numerical experiments show fast convergence, as nn grows, to the “two-third” quadrature rule of Hughes et al. (2010) for infinite domains.
Planar quadrature coil design using shielded-loop resonators
Stensgaard, A
1997-01-01
The shielded-loop resonator is known to have a low capacitive sample loss due to a perfect balancing. In this paper, it is demonstrated that shielded-loop technology also can be used to improve design of planar quadrature coils. Both a dual-loop circuit and especially a dual-mode circuit may...... benefit from use of shielded-loop resonators. Observations in measurements agree with theory for both a dual-loop coil and a dual-mode coil. The coils were designed for use as transmit/receive coil for 1H imaging and spectroscopy at 4.7 T in rat brain....
An automatically controlled predistorter for multilevel quadrature amplitude modulation
Namiki, J.
1983-05-01
In digital microwave transmission, the nonlinear characteristics in a high power amplifier, such as a TWT (traveling-wave tube), inhibit efficient output use. This note introduces a new predistorter control technique, and assesses the nonlinear compensation capability of a third-order predistorter incorporating this technique. Concerning 16-QAM (quadrature amplitude modulation), a 10 dB reduction in out-of-band emission and larger than 8 dB C/N improvement with respect to symbol error rate can be achieved at 3 dB TWT average output power backoff.
Photoacoustic Tomography using a Michelson Interferometer with Quadrature Phase Detection
Speirs, Rory W
2013-01-01
We present a pressure sensor based on a Michelson interferometer, for use in photoacoustic tomography. Quadrature phase detection is employed allowing measurement at any point on the mirror surface without having to retune the interferometer, as is typically required by Fabry-Perot type detectors. This opens the door to rapid full surface detection, which is necessary for clinical applications. Theory relating acoustic pressure to detected acoustic particle displacements is used to calculate the detector sensitivity, which is validated with measurement. Proof-of-concept tomographic images of blood vessel phantoms have been taken with sub-millimeter resolution at depths of several millimeters.
Principles and improvements of quadrature-based QKD
Hu, Wenhao; Shu, Di; Wang, Daqing; Liu, Yu
2010-11-01
An overview of quadrature-based quantum key distribution is provided. Beginning from the comparison between single-photon schema and continuous variable schema, the article focuses on the classical and state-of-art protocols. Protocols' main procedures and security analysis are introduced, which includes the methods under individual attack and collective attack. Then recent development of unconditional security proof is introduced including the optimality of Gaussian attack and de Finetti theorem. Introduction towards discrete modulated schemas' security proof is also made. At last, the article discusses experimental realization of various protocols and the main trend in this field.
In-phase and quadrature imbalance modeling, estimation, and compensation
Li, Yabo
2013-01-01
This book provides a unified IQ imbalance model and systematically reviews the existing estimation and compensation schemes. It covers the different assumptions and approaches that lead to many models of IQ imbalance. In wireless communication systems, the In-phase and Quadrature (IQ) modulator and demodulator are usually used as transmitter (TX) and receiver (RX), respectively. For Digital-to-Analog Converter (DAC) and Analog-to-Digital Converter (ADC) limited systems, such as multi-giga-hertz bandwidth millimeter-wave systems, using analog modulator and demodulator is still a low power and l
Solvability of a Lie algebra of vector fields implies their integrability by quadratures
Cariñena, J. F.; Falceto, F.; Grabowski, J.
2016-10-01
We present a substantial generalisation of a classical result by Lie on integrability by quadratures. Namely, we prove that all vector fields in a finite-dimensional transitive and solvable Lie algebra of vector fields on a manifold can be integrated by quadratures.
The Nature of the Nodes, Weights and Degree of Precision in Gaussian Quadrature Rules
Prentice, J. S. C.
2011-01-01
We present a comprehensive proof of the theorem that relates the weights and nodes of a Gaussian quadrature rule to its degree of precision. This level of detail is often absent in modern texts on numerical analysis. We show that the degree of precision is maximal, and that the approximation error in Gaussian quadrature is minimal, in a…
Quadrature formulas for classes of functions with bounded mixed derivative or difference
汪和平
1997-01-01
Quadrature formulas are considered for classes of smooth functions Wpr, Bpr,(?) with bounded mixed derivative or difference. For the classes of functions indicated above, the result that quadrature formulas constructed with the help of number-theoretic methods are optimal (in the sense of order) is proved, and the optimal order of the error estimates is obtained.
Novel IQ imbalance and offset compensation techniques for quadrature mixing radio transceivers
De Witt, JJ
2006-09-01
Full Text Available Despite the advantages that quadrature mixing offers to radio front-ends, its practical use has been limited due to its sensitivity towards gain and phase mismatches between its in-phase and quadrature channels. DC offsets are also a problem when a...
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.
A PLL Exploiting Sub-Sampling of the VCO Output to Reduce In-band Phase Noise
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.
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.
A PLL Exploiting Sub-Sampling of the VCO Output to Reduce In-band Phase Noise
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.
LC振荡器的设计要点%Design Issues for Cross-Coupled LC Oscillators
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.
Agachev, J. R.; Galimyanov, A. F.
2016-11-01
In this paper the method of mechanical quadrature solutions fractional integral equation. Computational scheme quadrature method is based on the quadrature formula of rectangles with equidistant nodes, which is the formula of the highest trigonometric degree of accuracy, using a regularizing parameter. This decision is taken for the approximate trigonometric interpolation polynomial constructed from the values that make up the solution of the quadrature method. The substantiation of the method in Holder spaces.
Multipole-preserving quadratures for discretization of functions
Genovese, Luigi
2015-01-01
Discretizing an analytic function on a uniform real-space grid is often done via a straightforward collocation method. This is ubiquitous in all areas of computational physics and quantum chemistry. An example in Density Functional Theory is given by the local external potential describing the interaction between ions and electrons. Also notable examples are given by the analytic functions defining compensation charges for range-separated electrostatic treatments. The accuracy of the collocation method used is therefore very important for the reliability of subsequent treatments like self-consistent field solutions of the electronic structure problems. When the real-space grid is too coarse, the collocation method introduces numerical artifacts typical of real-space treatments, like the so-called egg-box error, that may spoil the numerical stability of the description. We present in this paper a new quadrature scheme that is able to exactly preserve the multipoles of a given analytic function for a wide range...
Design of an MRI quadrature-data acquisition card
无
2006-01-01
A design of a quadrature-data acquisition card based on peripheral component interconnect (PCI) bus for mini-type magnetic resonance imaging (MRI) system is reported. It uses two high speed analog-to-digital converters (ADCs) to sample the MRI signals and two static random access memories (SRAMs) to store the data which will be read to the computer by PCI bus after sampling. All the logic control signals on the card are generated by the field programmable gate array (FPGA). The software Foundation3.1 is used to design the FPGA and achieve useful result after simulating and implementing. The card has some merits that normal commercial cards do not have. For example, the sampling parameters can be varied according to different pulse sequences.
Increasing the Reliability of Adaptive Quadrature Using Explicit Interpolants
Gonnet, Pedro
2010-01-01
We present two new adaptive quadrature routines. Both routines differ from previously published algorithms in many aspects, most significantly in how they represent the integrand, how they treat non-numerical values of the integrand, how they deal with improper divergent integrals and how they estimate the integration error. The main focus of these improvements is to increase the reliability of the algorithms without significantly impacting their efficiency. Both algorithms are implemented in Matlab and tested using both the ``families'' suggested by Lyness and Kaganove and the battery test used by Gander and Gautschi and Kahaner. They are shown to be more reliable, albeit in some cases less efficient, than other commonly-used adaptive integrators.
Two-step greedy algorithm for reduced order quadratures
Antil, Harbir; Herrmann, Frank; Nochetto, Ricardo H; Tiglio, Manuel
2012-01-01
We present an algorithm to generate application-specific, global reduced order quadratures (ROQ) for multiple fast evaluations of weighted inner products between parameterized functions. If a reduced basis (RB) or any other projection-based model reduction technique is applied, the dimensionality of integrands is reduced dramatically; however, the cost of evaluating the reduced integrals still scales as the size of the original problem. In contrast, using discrete empirical interpolation (DEIM) points as ROQ nodes leads to a computational cost which depends linearly on the dimension of the reduced space. Generation of a reduced basis via a greedy procedure requires a training set, which for products of functions can be very large. Since this direct approach can be impractical in many applications, we propose instead a two-step greedy targeted towards approximation of such products. We present numerical experiments demonstrating the accuracy and the efficiency of the two-step approach. The presented ROQ are ex...
Single mode quadrature entangled light from room temperature atomic vapour
Wasilewski, W; Jensen, K; Madsen, L S; Krauter, H; Polzik, E S
2009-01-01
We analyse a novel squeezing and entangling mechanism which is due to correlated Stokes and anti-Stokes photon forward scattering in a multi-level atom vapour. Following the proposal we present an experimental demonstration of 3.5 dB pulsed frequency nondegenerate squeezed (quadrature entangled) state of light using room temperature caesium vapour. The source is very robust and requires only a few milliwatts of laser power. The squeezed state is generated in the same spatial mode as the local oscillator and in a single temporal mode. The two entangled modes are separated by twice the Zeeman frequency of the vapour which can be widely tuned. The narrow-band squeezed light generated near an atomic resonance can be directly used for atom-based quantum information protocols. Its single temporal mode characteristics make it a promising resource for quantum information processing.
Quadrature Uncertainty and Information Entropy of Quantum Elliptical Vortex States
Banerji, Anindya; Singh, Ravindra Pratap; Chowdhury, Saurav; Bandyopadhyay, Abir
2013-01-01
We study the quadrature uncertainty of the quantum elliptical vortex state using the associated Wigner function. Deviations from the minimum uncertainty states were observed due to the absence of the Gaussian nature. In our study of the entropy, we noticed that with increasing vorticity, entropy increases for both the modes. We further observed that, there exists an optimum value of ellipticity which gives rise to maximum entanglement of the two modes of the quantum elliptical vortex states. A further increase in ellipticity reduces the entropy thereby resulting in a loss of information carrying capacity. We check the validity of the entropic inequality relations, namely the subaddivity and the Araki-Lieb inequality. The later was satisfied only for a very small range of the ellipticity of the vortex while the former seemed to be valid at all values.
Log-Domain Current-mode Quadrature Sinusoidal Oscillator
P. Prommee
2011-09-01
Full Text Available A log-domain current-mode quadrature sinusoidal oscillator based on lossless integrators is presented. The circuit is a direct realization of a first-order differential equation for obtaining the lossy and lossless integrators. Each of the log-domain lossless integrators is realized by using only NPN transistors and a grounded capacitor for achieving low-power and fast response. The proposed oscillator uses two-lossless integrator loop which can be electronically tuned through bias currents. A validated BJT model which is used in SPICE simulation operated from a single power supply as low as 2.5V. The oscillation frequency is controlled over four decades of frequency. The total harmonic distortions for two-phases QSO (12MHz is obtained around 0.93% which enables fully integrated in telecommunication systems. The proposed circuit is also suitable for high-frequency applications. Nonideality studies are included and PSpice simulation results confirm the theoretical results.
Quadrature phase interferometer for high resolution force spectroscopy
Paolino, Pierdomenico; Bellon, Ludovic
2013-01-01
In this article, we present a deflection measurement setup for Atomic Force Microscopy (AFM). It is based on a quadrature phase differential interferometer: we measure the optical path difference between a laser beam reflecting above the cantilever tip and a reference beam reflecting on the static base of the sensor. A design with very low environmental susceptibility and another allowing calibrated measurements on a wide spectral range are described. Both enable a very high resolution (down to $2.5E-15 m/sqrt{Hz}$), illustrated by a thermal noise measurement on an AFM cantilever. A quick review shows that our precision is equaling or outperforming the best results reported in the literature, but for a much larger deflection range, up to a few microns.
Investigation of turbulent plane mixing layer using generalized differential quadrature
Basirat Tabrizi, H.; Rezaei Niya, S.M.; Fariborz, S.J. [Amirkabir Univ. of Tech., Mechanical Engineering Dept., Tehran (Iran, Islamic Republic of)]. E-mail: hbasirat@aut.ac.ir; H.Basirat@dal.ca
2004-07-01
There is considerable interest in two-dimensional turbulent mixing layer, to name a few e.g. nature, combustion chamber, premixers of gas turbine combustor and many other technological applications. There features are the presence of large vortical structure, free turbulent characteristics, asymptotic behavior, faster growth rate. Some of the parameters that are known to affect the mixing layer behavior are investigated through the numerical models and experimental analysis during these past decades. A suitable solution for turbulent plane mixing layer requires the use of variable mesh size and an appropriate discretization scheme. The Generalized Differential Quadrature (GDQ) method is utilized to solve the problem. It can be a tool for evaluating the equations obtained for plane mixing layer. The present approach works well by refining mesh size, simplifying the calculation algorithms and less time for calculation anticipated. The numerical simulation is compared with the reported numerical and experimental results of others. (author)
An integrated source of broadband quadrature squeezed light
Hoff, Ulrich B; Andersen, Ulrik L
2015-01-01
An integrated silicon nitride resonator is proposed as an ultra-compact source of bright single-mode quadrature squeezed light at 850 nm. Optical properties of the device are investigated and tailored through numerical simulations, with particular attention paid to loss associated with interfacing the device. An asymmetric double layer stack waveguide geometry with inverse vertical tapers is proposed for efficient and robust fibre-chip coupling, yielding a simulated total loss of -0.75 dB/facet. We assess the feasibility of the device through a full quantum noise analysis and derive the output squeezing spectrum for intra-cavity pump self-phase modulation. Subject to standard material loss and detection efficiencies, we find that the device holds promises for generating substantial quantum noise squeezing over a bandwidth exceeding 1 GHz. In the low-propagation loss regime, approximately -7 dB squeezing is predicted for a pump power of only 50 mW.
Induced polarization of volcanic rocks. 1Surface versus quadrature conductivity
Revil, A.; Breton, M. Le; Niu, Q.; Wallin, E.; Haskins, E.; Thomas, D. M.
2016-11-01
We performed complex conductivity measurements on 28 core samples from the hole drilled for the Humu´ula Groundwater Research Project (Hawai´i Island, HI, USA). The complex conductivity measurements were performed at 4 different pore water conductivities (0.07, 0.5, 1.0 or 2.0, and 10 S m-1 prepared with NaCl) over the frequency range 1 mHz to 45 kHz at 22 ± 1°C. The in-phase conductivity data are plotted against the pore water conductivity to determine, sample by sample, the intrinsic formation factor and the surface conductivity. The intrinsic formation factor is related to porosity by Archie's law with an average value of the cementation exponent m of 2.45, indicating that only a small fraction of the connected pore space controls the transport properties. Both the surface and quadrature conductivities are found to be linearly related to the cation exchange capacity of the material, which was measured with the cobalt hexamine chloride method. Surface and quadrature conductivities are found to be proportional to each other like for sedimentary siliclastic rocks. A Stern layer polarization model is used to explain these experimental results. Despite the fact that the samples contain some magnetite (up to 5% wt.), we were not able to identify the effect of this mineral on the complex conductivity spectra. These results are very encouraging in showing that galvanometric induced polarization measurements can be used in volcanic areas to separate the bulk from the surface conductivity and therefore to define some alteration attributes. Such a goal cannot be achieved with resistivity alone.
Induced polarization of volcanic rocks - 1. Surface versus quadrature conductivity
Revil, A.; Le Breton, M.; Niu, Q.; Wallin, E.; Haskins, E.; Thomas, D. M.
2017-02-01
We performed complex conductivity measurements on 28 core samples from the hole drilled for the Humu'ula Groundwater Research Project (Hawai'i Island, HI, USA). The complex conductivity measurements were performed at 4 different pore water conductivities (0.07, 0.5, 1.0 or 2.0, and 10 S m-1 prepared with NaCl) over the frequency range 1 mHz to 45 kHz at 22 ± 1 °C. The in-phase conductivity data are plotted against the pore water conductivity to determine, sample by sample, the intrinsic formation factor and the surface conductivity. The intrinsic formation factor is related to porosity by Archie's law with an average value of the cementation exponent m of 2.45, indicating that only a small fraction of the connected pore space controls the transport properties. Both the surface and quadrature conductivities are found to be linearly related to the cation exchange capacity of the material, which was measured with the cobalt hexamine chloride method. Surface and quadrature conductivities are found to be proportional to each other like for sedimentary siliclastic rocks. A Stern layer polarization model is used to explain these experimental results. Despite the fact that the samples contain some magnetite (up to 5 per cent wt.), we were not able to identify the effect of this mineral on the complex conductivity spectra. These results are very encouraging in showing that galvanometric induced polarization measurements can be used in volcanic areas to separate the bulk from the surface conductivity and therefore to define some alteration attributes. Such a goal cannot be achieved with resistivity alone.
On-Wafer Measurement of a Silicon-Based CMOS VCO at 324 GHz
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.
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.
Gaussian quadrature for splines via homotopy continuation: Rules for C2 cubic splines
Barton, Michael
2015-10-24
We introduce a new concept for generating optimal quadrature rules for splines. To generate an optimal quadrature rule in a given (target) spline space, we build an associated source space with known optimal quadrature and transfer the rule from the source space to the target one, while preserving the number of quadrature points and therefore optimality. The quadrature nodes and weights are, considered as a higher-dimensional point, a zero of a particular system of polynomial equations. As the space is continuously deformed by changing the source knot vector, the quadrature rule gets updated using polynomial homotopy continuation. For example, starting with C1C1 cubic splines with uniform knot sequences, we demonstrate the methodology by deriving the optimal rules for uniform C2C2 cubic spline spaces where the rule was only conjectured to date. We validate our algorithm by showing that the resulting quadrature rule is independent of the path chosen between the target and the source knot vectors as well as the source rule chosen.
Adaptive quadrature-polybinary detection in super-Nyquist WDM systems.
Chen, Sai; Xie, Chongjin; Zhang, Jie
2015-03-23
We propose an adaptive detection technique in super-Nyquist wavelength-division-multiplexed (WDM) polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) systems, where a QPSK signal is digitally converted to a quadrature n-level polybinary signal followed by a MLSE detector at the receiver, and study the performance of quadrature-duobinary and quadrature four-level polybinary signals using this detection technique. We change the level of the quadrature-polybinary modulation at the coherent receiver according to the channel spacing of a super-Nyquist system. Numerical studies show that the best performance can be achieved by choosing different modulation levels at the receiver in adaption to the channel spacing. In the experiment, we demonstrate the transmission of 3-channel 112-Gbit/s PDM-QPSK signals at a 20-GHz channel spacing, which is detected as a quadrature four-level polybinary signal, with performance comparable to PDM 16-ary quadrature-amplitude modulation (16QAM) at the same bit rate.
Quadrature phase-shift error analysis using a homodyne laser interferometer.
Gregorcic, Peter; Pozar, Tomaz; Mozina, Janez
2009-08-31
The influence of quadrature phase shift on the measured displacement error was experimentally investigated using a two-detector polarizing homodyne laser interferometer with a quadrature detection system. Common nonlinearities, including the phase-shift error, were determined and effectively corrected by a robust data-processing algorithm. The measured phase-shift error perfectly agrees with the theoretically determined phase-shift error region. This error is systematic, periodic and severely asymmetrical around the nominal displacement value. The main results presented in this paper can also be used to assess and correct the detector errors of other interferometric and non-interferometric displacement-measuring devices based on phase-quadrature detection.
Uncontracted Rys Quadrature Implementation of up to G Functions on Graphical Processing Units.
Asadchev, Andrey; Allada, Veerendra; Felder, Jacob; Bode, Brett M; Gordon, Mark S; Windus, Theresa L
2010-03-09
An implementation is presented of an uncontracted Rys quadrature algorithm for electron repulsion integrals, including up to g functions on graphical processing units (GPUs). The general GPU programming model, the challenges associated with implementing the Rys quadrature on these highly parallel emerging architectures, and a new approach to implementing the quadrature are outlined. The performance of the implementation is evaluated for single and double precision on two different types of GPU devices. The performance obtained is on par with the matrix-vector routine from the CUDA basic linear algebra subroutines (CUBLAS) library.
Optimal displacement in apparent motion and quadrature models of motion sensing
Watson, Andrew B.
1990-01-01
A grating appears to move if it is displaced by some amount between two brief presentations, or between multiple successive presentations. A number of recent experiments have examined the influence of displacement size upon either the sensitivity to motion, or upon the induced motion aftereffect. Several recent motion models are based upon quadrature filters that respond in opposite quadrants in the spatiotemporal frequency plane. Predictions of the quadrature model are derived for both two-frame and multiframe displays. Quadrature models generally predict an optimal displacement of 1/4 cycle for two-frame displays, but in the multiframe case the prediction depends entirely on the frame rate.
A Ku-band wide-tuning-range high-output-power VCO in InGaP/GaAs HBT technology
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).
Simon, M. K.; Li, L.
2003-08-01
We show that MIL-STD shaped offset quadrature phase-shift keying (SOQPSK), a highly bandwidth-efficient constant-envelope modulation, can be represented in the form of a cross-correlated trellis-coded quadrature modulation, a generic structure containing both memory and cross-correlation between the in-phase and quadrature-phase channels. Such a representation allows identification of the optimum form of receiver for MIL-STD SOQPSK and at the same time, through modification of the equivalent I and Q encoders to recursive types, allows for it to be embedded as the inner code of a serial or parallel (turbo-like) concatenated coding structure together with iterative decoding.
Effect of Correlated Non-Gaussian Quadratures on the Performance of Binary Modulations
Valentine A. Aalo
2011-01-01
Full Text Available The received signal in many wireless communication systems comprises of the sum of waves with random amplitudes and random phases. In general, the composite signal consists of correlated nonidentical Gaussian quadrature components due to the central limit theorem (CLT. However, in the presence of a small number of random waves, the CLT may not always hold and the quadrature components may not be Gaussian distributed. In this paper, we assume that the fading environment is such that the quadrature components follow a correlated bivariate Student-t joint distribution. Then, we derive the envelope distribution of the received signal and obtain new expressions for the exact and high signal-to-noise (SNR approximate average BER for binary modulations. It also turns out that the derived envelope pdf approaches the Rayleigh and Hoyt distributions as limiting cases. Using the derived envelope pdf, we investigate the effect of correlated nonidentical quadratures on the error rate performance of digital communication systems.
Relation between the field quadratures and the characteristic function of a mirror
Rodriguez L, B.M.; Moya C, H. [INAOE, Coordinacion de Optica, A.P. 51 y 216, 72000 Puebla (Mexico)
2004-07-01
We analyse the possibility of measuring the state of a movable mirror by using its interaction with a quantum field. We show that measuring the field quadratures allows us to reconstruct the characteristic function corresponding to the mirror state. (Author)
Cui, Junning; He, Zhangqiang; Jiu, Yuanwei; Tan, Jiubin; Sun, Tao
2016-09-01
The demand for minimal cyclic nonlinearity error in laser interferometry is increasing as a result of advanced scientific research projects. Research shows that the quadrature phase error is the main effect that introduces cyclic nonlinearity error, and polarization-mixing cross talk during beam splitting is the main error source that causes the quadrature phase error. In this paper, a new homodyne quadrature laser interferometer configuration based on nonpolarization beam splitting and balanced interference between two circularly polarized laser beams is proposed. Theoretical modeling indicates that the polarization-mixing cross talk is elaborately avoided through nonpolarizing and Wollaston beam splitting, with a minimum number of quadrature phase error sources involved. Experimental results show that the cyclic nonlinearity error of the interferometer is up to 0.6 nm (peak-to-valley value) without any correction and can be further suppressed to 0.2 nm with a simple gain and offset correction method.
Analysis of thin plates by the weak form quadrature element method
ZHONG HongZhi; YUE ZhiGuang
2012-01-01
The recently proposed weak form quadrature element method (QEM) is applied to flexural and vibrational analysis of thin plates.The integrals involved in the variational description of a thin plate are evaluated by an efficient numerical scheme and the partial derivatives at the integration sampling points are then approximated using differential quadrature analogs.Neither the grid pattern nor the number of nodes is fixed,being adjustable according to convergence need.The C1 continuity conditions characterizing the thin plate theory are discussed and the robustness of the weak form quadrature element for thin plates against shape distortion is examined.Examples are presented and comparisons with analytical solutions and the results of the finite element method are made to demonstrate the convergence and computational efficiency of the weak form quadrature element method.It is shown that the present formulation is applicable to thin plates with varying thickness as well as uniform plates.
Squeezed quadrature fluctuations in a gravitational wave detector using squeezed light.
Dwyer, S; Barsotti, L; Chua, S S Y; Evans, M; Factourovich, M; Gustafson, D; Isogai, T; Kawabe, K; Khalaidovski, A; Lam, P K; Landry, M; Mavalvala, N; McClelland, D E; Meadors, G D; Mow-Lowry, C M; Schnabel, R; Schofield, R M S; Smith-Lefebvre, N; Stefszky, M; Vorvick, C; Sigg, D
2013-08-12
Squeezed states of light are an important tool for optical measurements below the shot noise limit and for optical realizations of quantum information systems. Recently, squeezed vacuum states were deployed to enhance the shot noise limited performance of gravitational wave detectors. In most practical implementations of squeezing enhancement, relative fluctuations between the squeezed quadrature angle and the measured quadrature (sometimes called squeezing angle jitter or phase noise) are one limit to the noise reduction that can be achieved. We present calculations of several effects that lead to quadrature fluctuations, and use these estimates to account for the observed quadrature fluctuations in a LIGO gravitational wave detector. We discuss the implications of this work for quantum enhanced advanced detectors and even more sensitive third generation detectors.
Relation between the field quadratures and the characteristic function of a mirror
Rodríguez, B M
2002-01-01
We analyze the possibility of measuring the state of a movable mirror by using its interaction with a quantum field. We show that measuring the field quadratures allows to reconstruct the characteristic function corresponding to the mirror state.
Velocity envelope of vector flow estimation with spatial quadrature
Kerr, Richard F.; Anderson, Martin E.
2003-05-01
We present the results of two studies investigating the optimal aperture configuration for maximized lateral blood flow velocity estimation using Heterodyned Spatial Quadrature. Our objective was to determine the maximum velocities that can be estimated at Doppler angles of 90 degrees and 60 degrees with a bias of less than 5% for both uniform scatterer motion in a tissue-mimicking phantom and blood-mimicking fluid circulated through a wall-less vessel flow phantom. Constant flow rates ranging from 3.0 to 18.0 ml/sec were applied in the flow phantom, producing expected peak velocities of 15.0 to 89.8 cm/sec under laminar flow conditions. Velocity estimates were obtained at each flow rate using 256 trials, with each trial consisting of an ensemble of 32 vectors. For an f/1 receive geometry with bi-lobed Hamming apodization, all peak flow velocities tested were estimated to within 5% of their expected values for both 90 degree and 60 degree Doppler angles. An f/2 receive geometry featuring bi-lobed Blackman apodization generally provided accurate lateral velocity estimates up to 71.9 cm/sec for a Doppler angle of 90 degrees, and accurate lateral component estimates up to 50.1 cm/sec for a 60 degree Doppler angle. The implications of these findings will be discussed.
Sparse aerosol models beyond the quadrature method of moments
McGraw, Robert
2013-05-01
This study examines a class of sparse aerosol models derived from linear programming (LP). The widely used quadrature method of moments (QMOM) is shown to fall into this class. Here it is shown how other sparse aerosol models can be constructed, which are not based on moments of the particle size distribution. The new methods enable one to bound atmospheric aerosol physical and optical properties using arbitrary combinations of model parameters and measurements. Rigorous upper and lower bounds, e.g. on the number of aerosol particles that can activate to form cloud droplets, can be obtained this way from measurement constraints that may include total particle number concentration and size distribution moments. The new LP-based methods allow a much wider range of aerosol properties, such as light backscatter or extinction coefficient, which are not easily connected to particle size moments, to also be assimilated into a list of constraints. Finally, it is shown that many of these more general aerosol properties can be tracked directly in an aerosol dynamics simulation, using SAMs, in much the same way that moments are tracked directly in the QMOM.
Hollow vortices, capillary water waves and double quadrature domains
Crowdy, Darren G [Department of Mathematics, Imperial College London, 180 Queen' s Gate, London SW7 2AZ (United Kingdom); Roenby, Johan, E-mail: d.crowdy@imperial.ac.uk, E-mail: johan.roenby@gmail.com [DHI, Agern Allé 5, 2970 Hørsholm (Denmark)
2014-06-01
Two new classes of analytical solutions for hollow vortex equilibria are presented. One class involves a central hollow vortex, comprising a constant pressure region having non-zero circulation, surrounded by an n-polygonal array of point vortices with n⩾2. The solutions generalize the non-rotating polygonal point vortex configurations of Morikawa and Swenson (1971 Phys. Fluids 14 1058–73) to the case where the point vortex at the centre of the polygon is replaced by a hollow vortex. The results of Morikawa and Swenson would suggest that all equilibria for n≠3 will be linearly unstable to point vortex mode instabilities. However even the n = 3 case turns out to be unstable to a recently discovered displacement instability deriving from a resonance between the natural modes of an isolated circular hollow vortex. A second class of analytical solutions for periodic water waves co-travelling with a submerged point vortex row is also described. The analysis gives rise to new theoretical connections with free surface Euler flows with surface tension and, in particular, with Crapper's classical solutions for capillary water waves. It is pointed out that the equilibrium fluid regions found here have a mathematical interpretation as an abstract class of planar domains known as double quadrature domains. (ss 1)
Axisymmetric Consolidation of Unsaturated Soils by Differential Quadrature Method
Wan-Huan Zhou
2013-01-01
Full Text Available Axisymmetric consolidation in a sand drain foundation is a common problem in foundation engineering. In unsaturated soils, the excess pore-water and pore-air pressures simultaneously change during the consolidation procedure; and the solutions are not easy to obtain. The present paper uses the differential quadrature method (DQM for axisymmetric consolidation of unsaturated soils in a sand drain foundation. The radial seepage of sand drain foundation is considered based on the framework of Fredlund’s one-dimensional consolidation theory in unsaturated soils. With the use of Darcy’s law and Fick’s law, the polar governing equations of excess pore-air and pore-water pressures of axisymmetric consolidation are derived. By using DQM, the two governing equations are transformed into two sets of ordinary differential equations. Then the solutions of excess pore-water and pore-air pressures can be obtained by Rong-Kutta method. The DQM solution can be used to deal with the case of nonuniform initial pore-air and pore-water distributions. Finally, case studies are presented to investigate the behavior of axisymmetric consolidation of unsaturated soils. The convergence analysis and average degree of consolidation, the settlements in radial and vertical direction, and the effects of different initial excess pore pressure distributions are presented, and discussed in this paper.
Numerical Evaluation of CPV Boundary Integrals with Symmetrical Quadrature Schemes
马杭; 徐凯宇
2003-01-01
Stemming from the definition of the Cauchy principal values (CPV) integrals, a newly developed symmetrical quadrature scheme was proposed in the paper for the accurate numerical evaluation of the singular boundary integrals in the sense of CPV encountered in the boundary element method. In the case of inner-element singularities, the CPV integrals could be evaluated in a straightforward way by dividing the element into the symmetrical part and the remainder(s). And in the case of end-singularities, the CPV integrals could be evaluated simply by taking a tangential distance transformation of the integrand after cutting out a symmetrical tiny zone around the singular point. In both cases, the operations are no longer necessary before the numerical implementation, which involves the dull routine work to separate out singularities from the integral kernels. Numerical examples were presented for both the two-and the three-dimensional boundary integrals in elasticity. Comparing the numerical results with those by other approaches demonstrates the feasibility and the effectiveness of the proposed scheme.
Information entropy of Gegenbauer polynomials and Gaussian quadrature
Sánchez-Ruiz, J
2003-01-01
In a recent paper (Buyarov V S, Lopez-Artes P, Martinez-Finkelshtein A and Van Assche W 2000 J. Phys. A: Math. Gen. 33 6549-60), an efficient method was provided for evaluating in closed form the information entropy of the Gegenbauer polynomials C sup ( suplambda sup ) sub n (x) in the case when lambda = l element of N. For given values of n and l, this method requires the computation by means of recurrence relations of two auxiliary polynomials, P(x) and H(x), of degrees 2l - 2 and 2l - 4, respectively. Here it is shown that P(x) is related to the coefficients of the Gaussian quadrature formula for the Gegenbauer weights w sub l (x) = (1 - x sup 2) sup l sup - sup 1 sup / sup 2 , and this fact is used to obtain the explicit expression of P(x). From this result, an explicit formula is also given for the polynomial S(x) = lim sub n sub-> subinfinity P(1 - x/(2n sup 2)), which is relevant to the study of the asymptotic (n -> infinity with l fixed) behaviour of the entropy.
Lynggaard, Vibeke; May, Ole; Beauchamp, Alison;
2014-01-01
that learning and coping incorporated in cardiac rehabilitation will improve adherence in cardiac rehabilitation and may decrease morbidity and mortality. By describing learning and coping strategies the study aims to provide knowledge that can contribute to an increased transparency in patient education...... of cardiac rehabilitation it is important to develop patient education methods which can enhance adherence to this effective program. The LC-REHAB study aims to compare the effect of a new patient education strategy in cardiac rehabilitation called 'learning and coping' to that of standard care. Further...... the intervention group with learning and coping strategies incorporated into standard care in cardiac rehabilitation or the control group who receive the usual cardiac rehabilitation program. Learning and coping consists of two individual clarifying interviews, participation of experienced patients as educators...
声体波谐振器压控振荡器%VCO with a Film Bulk Acoustic Resonator
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.
Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods
Huiliang Cao
2016-01-01
Full Text Available This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC, Quadrature Force Correction (QFC and Coupling Stiffness Correction (CSC methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.
Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods.
Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun
2016-01-07
This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses' quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups' output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.
High-Order Quadratures for the Solution of Scattering Problems in Two Dimensions
2008-04-22
combination of high-order quadrature formulae, fast application of integral operators in Lippmann- Schwinger equations, and the stabilized biconjugate...functions in two and three dimensions; these are used to obtain rapidly convergent discretizations of Lippmann- Schwinger equations. The performance of the...Lippmann- Schwinger , High-Order, Quadratures, Singu- lar, Hankel 2 1 Introduction Forward scattering has been an active field of research in science
Free Vibration Analysis of Laminated Composite Beams Using Differential Quadrature Method
冯丽娟; 钟宏志; 郝照平; 吴德隆
2002-01-01
A higher-order theory for laminated composite beams is used to study the free vibration of laminated composite beams, and the differential quadrature method is employed to obtain the numerical solution of the governing differential equations. Free vibration analysis of beams with rectangular cross-section for various combinations of end conditions is studied. The results show that the differential quadrature method is reliable and accurate compared with other available results.
Fast and Accurate Computation of Gauss--Legendre and Gauss--Jacobi Quadrature Nodes and Weights
Hale, Nicholas
2013-03-06
An efficient algorithm for the accurate computation of Gauss-Legendre and Gauss-Jacobi quadrature nodes and weights is presented. The algorithm is based on Newton\\'s root-finding method with initial guesses and function evaluations computed via asymptotic formulae. The n-point quadrature rule is computed in O(n) operations to an accuracy of essentially double precision for any n ≥ 100. © 2013 Society for Industrial and Applied Mathematics.
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.
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.
VCO Design and Simulation Using TSMC 0.18 m Process to Meet IEEE802.11a Requirements
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.
Designing a Ring-VCO for RFID Transponders in 0.18 μm CMOS Process
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
Designing a ring-VCO for RFID transponders in 0.18 μm CMOS process.
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.
采用0．13 μm RF CMOS工艺的105 GHz VCO
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。
Designing a Ring-VCO for RFID Transponders in 0.18 μm CMOS Process
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.
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.
On the phase-noise and phase-error performances of multiphase LC CMOS VCOs
Andreani, Pietro; Wang, Xiaoyan
2004-01-01
This paper presents an analysis of phase noise in multiphase LC oscillators, and measurement results for several CMOS quadrature-voltage-controlled-oscillators (QVCOs) working in the 2-GHz frequency range. The phase noise data for a so-called BS-QVCO (- 140 dBc/Hz or less at 3 MHz frequency offset...... from the carrier, for a power consumption of 20.8 mW and a figure-of-merit of 184 dBc/Hz) show that phase noise performances are close to the previously derived limits. A systematic cause of departure from ideal quadrature between QVCO signals is also analyzed and measured experimentally, and a compact...... LC-tank layout that removes this source of phase error is proposed. A TS-QVCO designed with this technique shows a phase-noise figure-of-merit improvement of 4 dB, compared to a previous implementation. The measured equivalent phase error for all QVCOs is between 0.6degrees and 1degrees....
Design and Application of Quadrature Compensation Patterns in Bulk Silicon Micro-Gyroscopes
Yunfang Ni
2014-10-01
Full Text Available This paper focuses on the detailed design issues of a peculiar quadrature reduction method named system stiffness matrix diagonalization, whose key technology is the design and application of quadrature compensation patterns. For bulk silicon micro-gyroscopes, a complete design and application case was presented. The compensation principle was described first. In the mechanical design, four types of basic structure units were presented to obtain the basic compensation function. A novel layout design was proposed to eliminate the additional disturbing static forces and torques. Parameter optimization was carried out to maximize the available compensation capability in a limited layout area. Two types of voltage loading methods were presented. Their influences on the sense mode dynamics were analyzed. The proposed design was applied on a dual-mass silicon micro-gyroscope developed in our laboratory. The theoretical compensation capability of a quadrature equivalent angular rate no more than 412 °/s was designed. In experiments, an actual quadrature equivalent angular rate of 357 °/s was compensated successfully. The actual compensation voltages were a little larger than the theoretical ones. The correctness of the design and the theoretical analyses was verified. They can be commonly used in planar linear vibratory silicon micro-gyroscopes for quadrature compensation purpose.
Schuyler, Adam D; Maciejewski, Mark W; Stern, Alan S; Hoch, Jeffrey C
2015-01-01
Nonuniform sampling (NUS) in multidimensional NMR permits the exploration of higher dimensional experiments and longer evolution times than the Nyquist Theorem practically allows for uniformly sampled experiments. However, the spectra of NUS data include sampling-induced artifacts and may be subject to distortions imposed by sparse data reconstruction techniques, issues not encountered with the discrete Fourier transform (DFT) applied to uniformly sampled data. The characterization of these NUS-induced artifacts allows for more informed sample schedule design and improved spectral quality. The DFT–Convolution Theorem, via the point-spread function (PSF) for a given sampling scheme, provides a useful framework for exploring the nature of NUS sampling artifacts. In this work, we analyze the PSFs for a set of specially constructed NUS schemes to quantify the interplay between randomization and dimensionality for reducing artifacts relative to uniformly undersampled controls. In particular, we find a synergistic relationship between the indirect time dimensions and the “quadrature phase dimension” (i.e. the hypercomplex components collected for quadrature detection). The quadrature phase dimension provides additional degrees of freedom that enable partial-component NUS (collecting a subset of quadrature components) to further reduce sampling-induced aliases relative to traditional full-component NUS (collecting all quadrature components). The efficacy of artifact reduction is exponentially related to the dimensionality of the sample space. Our results quantify the utility of partial-component NUS as an additional means for introducing decoherence into sampling schemes and reducing sampling artifacts in high dimensional experiments. PMID:25899289
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
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.
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.
A Compact Ka-Band PHEMT MMIC Voltage Controlled Oscillator%紧凑型Ka波段PHEMT微波单片集成VCO
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.
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
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.
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
24 GHz Low Phase Noise MMIC Voltage Controlled Oscillator%24 GHz低相位噪声单片集成VCO
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.
Nichtlineare Analyse von LC-TANK VCOs unter Berücksichtigung parasitärer Substrateffekte
J. Przytarski
2009-05-01
Full Text Available In dieser Arbeit wird ein Konzept vorgestellt, die Schaltungsarchitektur des LC-Tank-VCOs im höherdimensionalen Zustandsraum zu modellieren. Dabei wurde die VCO-Schaltung auf dominante nichtlineare und asymmetrische Effekte näher untersucht. Das entwickelte Modell bildet die Grundlage für nachfolgende parameterabhängige Analysen der Oszillatorschaltung mittels der Andronov-Hopf Bifurkationsanalyse. Zu diesem Zweck wurde ein höherdimensionales Modell entwickelt, welches für die Bifurkationsanalyse auf ein System 2. Ordnung reduziert werden muss. Als mathematisches Hilfsmittel zur Ordnungsreduktion des Systems wird das Verfahren der Zentrumsmannigfaltigkeit verwendet. Das Differentialgleichungssystem wird sehr schaltungsnah aufgestellt, daraus resultiert der Vorteil einer genaueren Repräsentation des physikalischen Verhaltens der Schaltung. Ziel ist es möglichst viele Effekte die sich auf das Verhalten des VCOs auswirken können, mit zu berücksichtigen.
Nichtlineare Analyse von LC-TANK VCOs unter Berücksichtigung parasitärer Substrateffekte
Przytarski, J.; Bremer, J.-K.; Mathis, W.
2009-05-01
In dieser Arbeit wird ein Konzept vorgestellt, die Schaltungsarchitektur des LC-Tank-VCOs im höherdimensionalen Zustandsraum zu modellieren. Dabei wurde die VCO-Schaltung auf dominante nichtlineare und asymmetrische Effekte näher untersucht. Das entwickelte Modell bildet die Grundlage für nachfolgende parameterabhängige Analysen der Oszillatorschaltung mittels der Andronov-Hopf Bifurkationsanalyse. Zu diesem Zweck wurde ein höherdimensionales Modell entwickelt, welches für die Bifurkationsanalyse auf ein System 2. Ordnung reduziert werden muss. Als mathematisches Hilfsmittel zur Ordnungsreduktion des Systems wird das Verfahren der Zentrumsmannigfaltigkeit verwendet. Das Differentialgleichungssystem wird sehr schaltungsnah aufgestellt, daraus resultiert der Vorteil einer genaueren Repräsentation des physikalischen Verhaltens der Schaltung. Ziel ist es möglichst viele Effekte die sich auf das Verhalten des VCOs auswirken können, mit zu berücksichtigen.
Design of a quadrature surface coil for hyperpolarized 13C MRS cardiac metabolism studies in pigs
Giovannetti, G.; Frijia, F.; Hartwig, V.;
2013-01-01
This work describes the design of a quadrature surface coil constituted by a circular loop and a butterfly coil, employed in transmit/receive (TX/RX) mode for hyperpolarized 13C studies of pig heart with a clinical 3T scanner. The coil characterization is performed by developing an SNR model...... for coil performance evaluation in terms of coil resistance, sample-induced resistance and magnetic field pattern. Experimental SNR-vs.-depth profiles, extracted from the [1-13C]acetate phantom chemical shift image (CSI), showed good agreement with the theoretical SNR-vs.-depth profiles. Moreover......, the performance of the quadrature coil was compared with the single TX/RX circular and TX/RX butterfly coil, in order to verify the advantage of the proposed configuration over the single coils throughout the volume of interest for cardiac imaging in pig. Finally, the quadrature surface coil was tested...
Parrish, Robert M; Hohenstein, Edward G; Martínez, Todd J; Sherrill, C David
2013-05-21
We investigate the application of molecular quadratures obtained from either standard Becke-type grids or discrete variable representation (DVR) techniques to the recently developed least-squares tensor hypercontraction (LS-THC) representation of the electron repulsion integral (ERI) tensor. LS-THC uses least-squares fitting to renormalize a two-sided pseudospectral decomposition of the ERI, over a physical-space quadrature grid. While this procedure is technically applicable with any choice of grid, the best efficiency is obtained when the quadrature is tuned to accurately reproduce the overlap metric for quadratic products of the primary orbital basis. Properly selected Becke DFT grids can roughly attain this property. Additionally, we provide algorithms for adopting the DVR techniques of the dynamics community to produce two different classes of grids which approximately attain this property. The simplest algorithm is radial discrete variable representation (R-DVR), which diagonalizes the finite auxiliary-basis representation of the radial coordinate for each atom, and then combines Lebedev-Laikov spherical quadratures and Becke atomic partitioning to produce the full molecular quadrature grid. The other algorithm is full discrete variable representation (F-DVR), which uses approximate simultaneous diagonalization of the finite auxiliary-basis representation of the full position operator to produce non-direct-product quadrature grids. The qualitative features of all three grid classes are discussed, and then the relative efficiencies of these grids are compared in the context of LS-THC-DF-MP2. Coarse Becke grids are found to give essentially the same accuracy and efficiency as R-DVR grids; however, the latter are built from explicit knowledge of the basis set and may guide future development of atom-centered grids. F-DVR is found to provide reasonable accuracy with markedly fewer points than either Becke or R-DVR schemes.
Suzuki, Meisaku; Kanno, Atsushi; Yamamoto, Naokatsu; Sotobayashi, Hideyuki
2016-02-01
The effects of in-phase/quadrature-phase (IQ) imbalances are evaluated with a direct IQ down-converter in the W-band (75-110 GHz). The IQ imbalance of the converter is measured within a range of +/-10 degrees in an intermediate frequency of DC-26.5 GHz. 1-8-G-baud quadrature phase-shift keying (QPSK) signals are transmitted successfully with observed bit error rates within a forward error correction limit of 2×10-3 using radio over fiber (RoF) techniques. The direct down-conversion technique is applicable to next-generation high-speed wireless access communication systems in the millimeter-wave band.
On quadrature formulas for singular integral equations of the first and the second kind
Krenk, Steen
1975-01-01
It is shown that by proper choice of the collocation points singular integral equations of the first and the second kind can be integrated by use of the usual Gauss-Jacobi quadrature formula. Detailed formulas are given for various values of the index.......It is shown that by proper choice of the collocation points singular integral equations of the first and the second kind can be integrated by use of the usual Gauss-Jacobi quadrature formula. Detailed formulas are given for various values of the index....
Lobatto and Radau positive quadrature formulas for linear combinations of Jacobi polynomials
Bustamante, Jorge; Martíez-Cruz, Reinaldo
2012-01-01
For a given $\\theta\\in (-1,1)$, we find out all parameters $\\alpha,\\beta\\in \\{0,1\\}$ such that, there exists a linear combination of Jacobi polynomials $J_{n+1}^{(\\alpha,\\beta)}(x)-C J_{n}^{(\\alpha,\\beta)}(x)$ which generates a Lobatto (Radau) positive quadrature formula of degree of exactness \\textcolor{red}{$2n+2$ ($2n+1$)} and contains the point $\\theta$ as a node. These positive quadratures are very useful in studying problems in one-sided polynomial $L_1$ approximation.
Spectral/quadrature duality: Picard-Vessiot theory and finite-gap potentials
Brezhnev, Yurii V
2010-01-01
In the framework of differential Galois theory we treat classical spectral problem $\\Psi''-u(x)\\Psi=\\lambda\\Psi$ and its finite-gap potentials as exactly solvable in quadratures by Picard-Vessiot without involving special functions (the ideology goes back to works by J. Drach 1919). From this standpoint we inspect known facts and obtain new ones: an important formula for Psi-function, differential properties of Jacobian theta-functions, and Theta-function extension of Picard-Vessiot fields. We show that duality between spectral and quadrature approaches is realized through the Weierstrass permutation theorem for a logarithmic Abelian integral.
S. M. Sadatrasoul
2014-01-01
Full Text Available We introduce some generalized quadrature rules to approximate two-dimensional, Henstock integral of fuzzy-number-valued functions. We also give error bounds for mappings of bounded variation in terms of uniform modulus of continuity. Moreover, we propose an iterative procedure based on quadrature formula to solve two-dimensional linear fuzzy Fredholm integral equations of the second kind (2DFFLIE2, and we present the error estimation of the proposed method. Finally, some numerical experiments confirm the theoretical results and illustrate the accuracy of the method.
Quadrature effects on the accuracy of flux calculations in realistic atmospheres.
Box, M. A.; Trautmann, T.; Loughlin, P. E.
1993-12-01
The authors have investigated the accuracy of five different quadrature methods - equal steps in θ, equal steps in cos θ, Gaussian, double Gaussian and Gauss-Lobatto - on the accuracy of fluxes in realistic aerosol atmospheres, using the Gauss-Seidel method. In addition, a range of Gaussian quadrature stream numbers from two to 32 were compared. The atmospheric models considered are those recently presented by Lenoble, with the exception that the authors have used Henyey-Greenstein phase functions in place of Mie. The results should be easily reproduceable by any other workers interested in similar realistic atmospheres. A table of Gauss-Lobatto weights and points is provided as an appendix.
Some Numerical Quadrature Schemes of a Non-conforming Quadrilateral Finite Element
Xiao-fei GUAN; Ming-xia LI; Shao-chun CHEN
2012-01-01
Numerical quadrature schemes of a non-conforming finite element method for general second order elliptic problems in two dimensional (2-D) and three dimensional (3-D) space are discussed in this paper.We present and analyze some optimal numerical quadrature schemes. One of the schemes contains only three sampling points,which greatly improves the efficiency of numerical computations.The optimal error estimates are derived by using some traditional approaches and techniques.Lastly,some numerical results are provided to verify our theoretical analysis.
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.
Numerical quadrature and operator splitting in finite element methods for cardiac electrophysiology.
Krishnamoorthi, Shankarjee; Sarkar, Mainak; Klug, William S
2013-11-01
We study the numerical accuracy and computational efficiency of alternative formulations of the finite element solution procedure for the monodomain equations of cardiac electrophysiology, focusing on the interaction of spatial quadrature implementations with operator splitting and examining both nodal and Gauss quadrature methods and implementations that mix nodal storage of state variables with Gauss quadrature. We evaluate the performance of all possible combinations of 'lumped' approximations of consistent capacitance and mass matrices. Most generally, we find that quadrature schemes and lumped approximations that produce decoupled nodal ionic equations allow for the greatest computational efficiency, this being afforded through the use of asynchronous adaptive time-stepping of the ionic state variable ODEs. We identify two lumped approximation schemes that exhibit superior accuracy, rivaling that of the most expensive variationally consistent implementations. Finally, we illustrate some of the physiological consequences of discretization error in electrophysiological simulation relevant to cardiac arrhythmia and fibrillation. These results suggest caution with the use of semi-automated free-form tetrahedral and hexahedral meshing algorithms available in most commercially available meshing software, which produce nonuniform meshes having a large distribution of element sizes.
Serbes, Gorkem; Aydin, Nizamettin
2014-01-01
Quadrature signals are dual-channel signals obtained from the systems employing quadrature demodulation. Embolic Doppler ultrasound signals obtained from stroke-prone patients by using Doppler ultrasound systems are quadrature signals caused by emboli, which are particles bigger than red blood cells within circulatory system. Detection of emboli is an important step in diagnosing stroke. Most widely used parameter in detection of emboli is embolic signal-to-background signal ratio. Therefore, in order to increase this ratio, denoising techniques are employed in detection systems. Discrete wavelet transform has been used for denoising of embolic signals, but it lacks shift invariance property. Instead, dual-tree complex wavelet transform having near-shift invariance property can be used. However, it is computationally expensive as two wavelet trees are required. Recently proposed modified dual-tree complex wavelet transform, which reduces the computational complexity, can also be used. In this study, the denoising performance of this method is extensively evaluated and compared with the others by using simulated and real quadrature signals. The quantitative results demonstrated that the modified dual-tree-complex-wavelet-transform-based denoising outperforms the conventional discrete wavelet transform with the same level of computational complexity and exhibits almost equal performance to the dual-tree complex wavelet transform with almost half computational cost.
A Quantized Analog Delay for an ir-UWB Quadrature Downconversion Autocorrelation Receiver
Bagga, S.; Zhang, L.; Serdijn, W.A.; Long, J.R.; Busking, E.B.
2005-01-01
A quantized analog delay is designed as a requirement for the autocorrelation function in the quadrature downconversion autocorrelation receiver (QDAR). The quantized analog delay is comprised of a quantizer, multiple binary delay lines and an adder circuit. Being the foremost element, the quantizer
V. M. Stechenko
1982-12-01
Full Text Available The results of the study of quadrature bridge device to a range of 10 to 100 MHz and 30-300 MHz. The apparatus consists of two adders for magnetically lines and a constant phase shift of the phase shifter.
17th century arguments for the impossibility of the indefinite and the definite circle quadrature
Lützen, Jesper
2014-01-01
The classical problem of the quadrature (or equivalently the rectification) of the circle enjoyed a renaissance in the second half of the 17th century. The new analytic methods provided the means for the discovery of infinite expressions of and for the first attempts to prove impossibility statem...
Håvie, T.
1970-01-01
Some quadrature formulae using the derivatives of the integrand are discussed. As special cases are obtained generalizations of both the ordinary and the modified Romberg algorithms. In all cases the error terms are expressed in terms of Bernoulli polynomials and functions.
An unified framework for the computation of polynomial quadrature weights and errors
Graça, Mário M
2012-01-01
For the class of polynomial quadrature rules we show that conveniently chosen bases allow to compute both the weights and the theoretical error expression of a $n$-point rule via the undetermined coefficients method. As an illustration, the framework is applied to some classical rules such as Newton-Cotes, Adams-Bashforth, Adams-Moulton and Gaussian rules.
AM to PM noise conversion in a cross-coupled quadrature harmonic oscillator
Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens
2006-01-01
We derive the dynamic equations governing the cross-coupled quadrature oscillator, perturbed by noise, leading to an expression for the close-in phase noise. The theory shows that a nonlinear coupling transconductance results in AM-PM noise conversion close to the carrier, which increases...
Quadrature phase shift keying coherent state discrimination via a hybrid receiver
Müller, C. R.; Castaneda, Mario A. Usuga; Wittmann, C.;
2012-01-01
We propose and experimentally demonstrate a near-optimal discrimination scheme for the quadrature phase shift keying (QPSK) protocol. We show in theory that the performance of our hybrid scheme is superior to the standard scheme—heterodyne detection—for all signal amplitudes and underpin the pred...
MEMS-based LC tank with extended tuning range for multiband applications
Cazzorla, A.; Farinelli, P.; Urbani, L.; Sorrentino, R.; Margesin, B.
2016-09-01
This paper presents the modeling, simulations, and measurements of a compact multiband microelectromechanical (MEMS)-based LC tank resonator suitable for low phase noise voltage-controlled oscillators (VCOs). The resonator is based on a high-Q spiral inductor and high capacitance ratio varicap fully integrated in FBK-irst (Fondazione Bruno Kessler) MEMS manufacturing process. The design of the varicap is based on double-actuation mechanism with a mechanical central bond that inhibits the pull-in allowing for a theoretically infinite tuning ratio. The measurements have shown a total not continuous capacitance ratio (Cr) of 5.2 with a continuous variation of the capacitance values in the range 225 fF-600 fF which corresponds to a continuous capacitance ratio (Cr*) of 2.6. The performance repeatability, the power-handling capability, and the stability over time were tested on 10 samples showing a negligible variation of the capacitance values. The spiral inductor consists of a suspended gold membrane thick 5 µm in a circular shape which was modeled in order to optimize the quality factor (Q) in the frequency range 2-4 GHz. The measurement results show a Q of about 55 in the 2-4 GHz frequency band. The LC tank measurements show an overall tuning range better than of 45% in the 3.2-4.9 GHz frequency band, consisting of two continuous tuning ranges of 7.5% and 25%. The LC tank allowed the design of MEMS-based voltage-controlled oscillators (VCOs) with an overall tuning better than 60% in the frequency range 2.15 GHz-3.85 GHz and two separate regions of continuous tuning range. The VCO prototype will be fabricated on Surface Mount Technology on RO4350 laminate. The main figures of merit are presented in comparison with the state of the art.
Chen, Tianheng; Shu, Chi-Wang
2017-09-01
It is well known that semi-discrete high order discontinuous Galerkin (DG) methods satisfy cell entropy inequalities for the square entropy for both scalar conservation laws (Jiang and Shu (1994) [39]) and symmetric hyperbolic systems (Hou and Liu (2007) [36]), in any space dimension and for any triangulations. However, this property holds only for the square entropy and the integrations in the DG methods must be exact. It is significantly more difficult to design DG methods to satisfy entropy inequalities for a non-square convex entropy, and/or when the integration is approximated by a numerical quadrature. In this paper, we develop a unified framework for designing high order DG methods which will satisfy entropy inequalities for any given single convex entropy, through suitable numerical quadrature which is specific to this given entropy. Our framework applies from one-dimensional scalar cases all the way to multi-dimensional systems of conservation laws. For the one-dimensional case, our numerical quadrature is based on the methodology established in Carpenter et al. (2014) [5] and Gassner (2013) [19]. The main ingredients are summation-by-parts (SBP) operators derived from Legendre Gauss-Lobatto quadrature, the entropy conservative flux within elements, and the entropy stable flux at element interfaces. We then generalize the scheme to two-dimensional triangular meshes by constructing SBP operators on triangles based on a special quadrature rule. A local discontinuous Galerkin (LDG) type treatment is also incorporated to achieve the generalization to convection-diffusion equations. Extensive numerical experiments are performed to validate the accuracy and shock capturing efficacy of these entropy stable DG methods.
Magdenoska, Olivera
with only 12C or 13C carbons were very low or even not measurable and showed minimal or no interference to the spiked amount of nonlabeled standards and their stable isotope-labeled internal standards (SIL-IS). Finally the developed IP-RP LC-MS method was coupled to a quadrupole time of flight (QTOF) MS...
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
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.
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.
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.
A low-noise X-band microstrip VCO with 2.5 GHz tuning range using a GaN-on-SiC p-HEMT
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
一种中心频率可调的VCO电路设计%A Center Frequency Adjustable VCO Circuit Design
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.
Sidi, A.; Israeli, M.
1986-01-01
High accuracy numerical quadrature methods for integrals of singular periodic functions are proposed. These methods are based on the appropriate Euler-Maclaurin expansions of trapezoidal rule approximations and their extrapolations. They are used to obtain accurate quadrature methods for the solution of singular and weakly singular Fredholm integral equations. Such periodic equations are used in the solution of planar elliptic boundary value problems, elasticity, potential theory, conformal mapping, boundary element methods, free surface flows, etc. The use of the quadrature methods is demonstrated with numerical examples.
R.Mokhtari; A.Samadi Toodar; N.G.Chegini
2011-01-01
@@ We the extend application of the generalized differential quadrature method (GDQM) to solve some coupled nonlinear Schr(o)dinger equations.The cosine-based GDQM is employed and the obtained system of ordinary differential equations is solved via the fourth order Runge-Kutta method.The numerical solutions coincide with the exact solutions in desired machine precision and invariant quantities are conserved sensibly.Some comparisons with the methods applied in the literature are carried out.%We the extend application of the generalized differential quadrature method (GDQM) to solve some coupled nonlinear Schrodinger equations. The cosine-based GDQM is employed and the obtained system of ordinary differential equations is solved via the fourth order Runge-Kutta method. The numerical solutions coincide with the exact solutions in desired machine precision and invariant quantities are conserved sensibly. Some comparisons with the methods applied in the literature are carried out.
VDCC Based Dual-Mode Quadrature Sinusoidal Oscillator with Outputs at Appropriate Impedance Levels
Mayank Srivastava
2016-01-01
Full Text Available This article presents a new dual-mode (i.e. both current-mode and voltage-mode quadrature sinusoidal oscillator using two Voltage Differencing Current Conveyors (VDCCs, two resistors and two capacitors. The proposed configuration use only grounded passive elements and enjoys independent resistor/electronic tuning of both Condition of Oscillation (CO as well as Frequency of Oscillation (FO. The quadrature current and voltage mode outputs of this circuit are available at appropriate impedance terminals. The behavior of presented oscillator is also examined under non ideal/parasitic conditions. The validity of the proposed configuration has been confirmed by SPICE simulations with TSMC 0.18μm process parameters.
A fast integral equation method for solid particles in viscous flow using quadrature by expansion
Klinteberg, Ludvig af
2016-01-01
Boundary integral methods are advantageous when simulating viscous flow around rigid particles, due to the reduction in number of unknowns and straightforward handling of the geometry. In this work we present a fast and accurate framework for simulating spheroids in periodic Stokes flow, which is based on the completed double layer boundary integral formulation. The framework implements a new method known as quadrature by expansion (QBX), which uses surrogate local expansions of the layer potential to evaluate it to very high accuracy both on and off the particle surfaces. This quadrature method is accelerated through a newly developed precomputation scheme. The long range interactions are computed using the spectral Ewald (SE) fast summation method, which after integration with QBX allows the resulting system to be solved in M log M time, where M is the number of particles. This framework is suitable for simulations of large particle systems, and can be used for studying e.g. porous media models.
New Adaptive Method for IQ Imbalance Compensation of Quadrature Modulators in Predistortion Systems
Zareian, Hassan; Vakili, Vahid Tabataba
2009-12-01
Imperfections in quadrature modulators (QMs), such as inphase and quadrature (IQ) imbalance, can severely impact the performance of power amplifier (PA) linearization systems, in particular in adaptive digital predistorters (PDs). In this paper, we first analyze the effect of IQ imbalance on the performance of a memory orthogonal polynomials predistorter (MOP PD), and then we propose a new adaptive algorithm to estimate and compensate the unknown IQ imbalance in QM. Unlike previous compensation techniques, the proposed method was capable of online IQ imbalance compensation with faster convergence, and no special calibration or training signals were needed. The effectiveness of the proposed IQ imbalance compensator was validated by simulations. The results clearly show the performance of the MOP PD to be enhanced significantly by adding the proposed IQ imbalance compensator.
Gaussian quadrature and lattice discretization of the Fermi-Dirac distribution for graphene.
Oettinger, D; Mendoza, M; Herrmann, H J
2013-07-01
We construct a lattice kinetic scheme to study electronic flow in graphene. For this purpose, we first derive a basis of orthogonal polynomials, using as the weight function the ultrarelativistic Fermi-Dirac distribution at rest. Later, we use these polynomials to expand the respective distribution in a moving frame, for both cases, undoped and doped graphene. In order to discretize the Boltzmann equation and make feasible the numerical implementation, we reduce the number of discrete points in momentum space to 18 by applying a Gaussian quadrature, finding that the family of representative wave (2+1)-vectors, which satisfies the quadrature, reconstructs a honeycomb lattice. The procedure and discrete model are validated by solving the Riemann problem, finding excellent agreement with other numerical models. In addition, we have extended the Riemann problem to the case of different dopings, finding that by increasing the chemical potential the electronic fluid behaves as if it increases its effective viscosity.
A low reference spur quadrature phase-locked loop for UWB systems
Fu Haipeng; Cai Deyun; Ren Junyan; Li Wei; Li Ning
2011-01-01
This paper presents a low phase noise and low reference spur quadrature phase-locked loop (QPLL) circuit that is implemented as a part of a frequency synthesizer for China UWB standard systems.A glitch-suppressed charge pump (CP) is employed for reference spur reduction.By forcing the phase frequency detector and CP to operate in a linear region of its transfer function,the linearity of the QPLL is further improved.With the proposed series-quadrature voltage-controlled oscillator,the phase accuracy of the QPLL is guaranteed.The circuit is fabricated in the TSMC 0.13 μtm CMOS process and operated at 1.2-V supply voltage.The QPLL measures a phase noise of-95 dBc/Hz at 100-kHz offset and a reference spur of-71 dBc.The fully-integrated QPLL dissipates a current of 13 mA.
Time-resolved homodyne characterization of individual quadrature-entangled pulses
Wenger, J; Tualle-Brouri, R; Grangier, P; Wenger, Jerome; Ourjoumtsev, Alexei; Tualle-Brouri, Rosa; Grangier, Philippe
2005-01-01
We describe a simple and efficient setup to generate and characterize femtosecond quadrature-entangled pulses. Quantum correlations equivalent to about 2.5 dB squeezing are efficiently and easily reached using the non-degenerate parametric amplification of femtosecond pulses through a single-pass in a thin (0.1 mm) potassium niobate crystal. The entangled pulses are then individually sampled to characterize the non-separability and the entropy of formation of the states. The complete experiment is analysed in the time-domain, from the pulsed source of quadrature entanglement to the time-resolved homodyne detection. This particularity allows for applications in quantum communication protocols using continuous-variable entanglement.
Polyphase Structure Based Eigen Design of Two-Channel Quadrature Mirror Filter Bank
S. K. Agrawal
2014-09-01
Full Text Available This paper presents a method for the design of two-channel quadrature mirror filter (QMF banks with linear phase in frequency domain. Low-pass prototype filter of the QMF bank is implemented using polyphase decomposition. Prototype filter coefficients are optimized to minimize an objective function using eigenvalue-eigenvector approach without matrix inversion. The objective function is formulated as a weighted sum of four terms, pass-band error and stop-band residual energy of low-pass analysis filter, the square error of the overall transfer function at the quadrature frequency and amplitude distortion of the filter bank. The simulation results clearly show that the proposed method requires less computational efforts in comparison to the other state-of-art existing design methods.
Buckling analysis of an orthotropic thin shell of revolution using differential quadrature
Redekop, D. [Department of Mechanical Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, ON, K1N 6N5 (Canada)]. E-mail: dredekop@tesla.cc.uottawa.ca
2005-08-01
A method is developed to predict the buckling characteristics of an orthotropic shell of revolution of arbitrary meridian subjected to a normal pressure. The solution is given within the context of the linearized Sanders-Budiansky shell buckling theory and makes use of the differential quadrature method. Numerical results for buckling pressures and mode shapes are given for complete toroidal shells. Both completely free shells and shells with circumferential line restraints are covered. The loadings considered consist either of uniform pressure or circumferential bands of constant pressure. It is demonstrated that the differential quadrature method is numerically stable and converges. For isotropic toroidal shells, good agreement is observed with previously published analytical and finite element results. New results for buckling pressures and mode numbers are given for orthotropic shells and for band loaded shells.
Parallel-coupled dual racetrack silicon micro-resonators for quadrature amplitude modulation.
Integlia, Ryan A; Yin, Lianghong; Ding, Duo; Pan, David Z; Gill, Douglas M; Jiang, Wei
2011-08-01
A parallel-coupled dual racetrack silicon micro-resonator structure is proposed and analyzed for M-ary quadrature amplitude modulation. The over-coupled, critically coupled, and under-coupled scenarios are systematically studied. Simulations indicate that only the over-coupled structures can generate arbitrary M-ary quadrature signals. Analytic study shows that the large dynamic range of amplitude and phase of a modulated over-coupled structure stems from the strong cross-coupling between two resonators, which can be understood through a delicate balance between the direct sum and the "interaction" terms. Potential asymmetries in the coupling constants and quality factors of the resonators are systematically studied. Compensations for these asymmetries by phase adjustment are shown feasible.
L. O. Fichte
2006-01-01
Full Text Available Boundary Integral Equation formulations can be used to describe electromagnetic shielding problems. Yet, this approach frequently leads to integrals which contain a singularity and an oscillating part. Those integrals are difficult to handle when integrated naivly using standard integration techniques, and in some cases even a very high number of integration nodes will not lead to precise results. We present a method for the numerical quadrature of an integral with a logarithmic singularity and a cosine oscillator: a modified Filon-Lobatto quadrature for the oscillating parts and an integral transformation based on the error function for the singularity. Since this integral can be solved analytically, we are in a position to verify the results of our investigations, with a focus on precision and computation time.
New Adaptive Method for IQ Imbalance Compensation of Quadrature Modulators in Predistortion Systems
Hassan Zareian
2009-01-01
Full Text Available Imperfections in quadrature modulators (QMs, such as inphase and quadrature (IQ imbalance, can severely impact the performance of power amplifier (PA linearization systems, in particular in adaptive digital predistorters (PDs. In this paper, we first analyze the effect of IQ imbalance on the performance of a memory orthogonal polynomials predistorter (MOP PD, and then we propose a new adaptive algorithm to estimate and compensate the unknown IQ imbalance in QM. Unlike previous compensation techniques, the proposed method was capable of online IQ imbalance compensation with faster convergence, and no special calibration or training signals were needed. The effectiveness of the proposed IQ imbalance compensator was validated by simulations. The results clearly show the performance of the MOP PD to be enhanced significantly by adding the proposed IQ imbalance compensator.
Bruce, Adam L
2015-01-01
We show the traditional rocket problem, where the ejecta velocity is assumed constant, can be reduced to an integral quadrature of which the completely non-relativistic equation of Tsiolkovsky, as well as the fully relativistic equation derived by Ackeret, are limiting cases. By expanding this quadrature in series, it is shown explicitly how relativistic corrections to the mass ratio equation as the rocket transitions from the Newtonian to the relativistic regime can be represented as products of exponential functions of the rocket velocity, ejecta velocity, and the speed of light. We find that even low order correction products approximate the traditional relativistic equation to a high accuracy in flight regimes up to $0.5c$ while retaining a clear distinction between the non-relativistic base-case and relativistic corrections. We furthermore use the results developed to consider the case where the rocket is not moving relativistically but the ejecta stream is, and where the ejecta stream is massless.
Trade-off between phase-noise and signal quadrature in unilaterally coupled oscillators
Djurhuus, Torsten; Krozer, Viktor; Vidkjær, Jens
2005-01-01
We present a comprehensive nonlinear analysis of coupled oscillators and examine the trade-off between phase-noise of the oscillator and the quadrature precision. We show that asymmetry gives rise to amplitude and phase imbalance which are proportional to the inverse and inverse square......, respectively, of the relative coupling strength. It is shown that the level of AM-PM is determined by the nonlinearity of the coupling transconductance. The 3dB noise reduction in close-to-carrier phase-noise in quadrature oscillators due to mutual coupling is lost to the extra AM-PM noise for large coupling...... strengths. The additional contribution of the internal noise sources in the coupling circuit together with the AM-PM noise contribution explains why the 3dB noise reduction is rarely seen in measurements of this particular circuit....
Comparison of Spectral and Differential Quadrature Methods for Solving the Burger-Huxley Equation
Jalal Izadian
2013-06-01
Full Text Available In this paper, the Burger-Huxley equation is solved by two methods: Spectral method and Differential Quadrature Method (DQM. The Chebyshev-Gauss-Lobatto point distribution is utilized in spectral method. The integrity and computational accuracy of the spectral method in solving some test problems are demonstrated through various case studies. The results show that spectral method is more accurate than DQM.
Pozar, Tomaz; Gregorcic, Peter; Mozina, Janez
2011-03-20
We present the influence of alignment and the real properties of optical components on the performance of a two-detector homodyne displacement-measuring quadrature laser interferometer. An experimental method, based on the optimization of visibility and sensitivity, was established and theoretically described to assess the performance and stability of the interferometer. We show that the optimal performance of such interferometers is achieved with the iterative alignment procedure described.
Variable-length balanced codes for quadrature phase shift keyed systems
Xin Tu
2015-10-01
Full Text Available The authors outline an approach to construct capacity-approaching balanced quadrature phase shift keyed (QPSK codes. These codes ensure an equal number of different symbol values and many symbol transitions in the encoded sequence in order to assist practical demodulators to accurately recover symbol values. Their codes are comprised of instantaneously decodable variable-length codewords that exhibit excellent performance with average code rates higher than previously reported fixed-length balanced QPSK codes.
New uncertainties in QCD-QED rescaling factors using quadrature method
Mahadev Patgiri; N Nimai Singh
2005-12-01
In this paper we briefly outline the quadrature method for estimating uncertainties in a function which depends on several variables, and apply it to estimate the numerical uncertainties in QCD-QED rescaling factors. We employ here the one-loop order in QED and three-loop order in QCD evolution equations of the fermion mass renormalisation. Our present calculation is found to be new and also reliable when compared to the earlier values employed by various authors.
Noiseless phase quadrature amplification via an electro-optic feed-forward technique
Buchler, B C; Ralph, T C; Buchler, Ben C.; Huntington, Elanor H.; Ralph, Timothy C.
1999-01-01
Theoretical results are presented which show that noiseless phase quadrature amplification is possible, and limited experimentally only by the efficiency of the phase detection system. Experimental results obtained using a Nd:YAG laser show a signal gain of 10dB and a signal transfer ratio of T_s=0.9. This result easily exceeds the standard quantum limit for signal transfer. The results also explicitly demonstrate the phase sensitive nature of the amplification process.
Quadrature-free spline method for two-dimensional Navier-Stokes equation
HU Xian-liang; HAN Dan-fu
2008-01-01
In this paper,a quadrature-free scheme of spline method for two-dimensional Navier-Stokes equation is derived,which can dramatically improve the efficiency of spline method for fluid problems proposed by Lai and Wenston(2004). Additionally,the explicit formulation for boundary condition with up to second order derivatives is presented. The numerical simulations on several benchmark problems show that the scheme is very efficient.
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
The best quadrature based on given Hermite information for the Sobolev class KWr[a,b
WANG; Xinghua; YANG; Shijun
2006-01-01
As usual, denote by KWr[a,b] the Sobolev class consisting of every function whose (r-1)th derivative is absolutely continuous on the interval [a,b] and rth derivative is bounded by K a.e. In [a,b]. For a function f ∈ KWr[a,b], its values and derivatives up to r-1 order at a set of nodes x are known. These values are said to be the given Hermite information.This work reports the results on the best quadrature based on the given Hermite information for the class KWr[a,b]. Existence and concrete construction issue of the best quadrature are settled down by a perfect spline interpolation. It turns out that the best quadrature depends on a system of algebraic equations satisfied by a set of free nodes of the interpolation perfect spline. From our another new result, it is shown that the system can be converted in a closed form to two single-variable polynomial equations, each being of degree approximately r/2. As a by-product,the best interpolation formula for the class KWr[a,b] is also obtained.
Wang, Dongdong; Li, Xiwei; Pan, Feixu
2016-11-01
A simple and unified finite element formulation is presented for superconvergent eigenvalue computation of wave equations ranging from 1D to 3D. In this framework, a general method based upon the so called α mass matrix formulation is first proposed to effectively construct 1D higher order mass matrices for arbitrary order elements. The finite elements discussed herein refer to the Lagrangian type of Lobatto elements that take the Lobatto points as nodes. Subsequently a set of quadrature rules that exactly integrate the 1D higher order mass matrices are rationally derived, which are termed as the superconvergent quadrature rules. More importantly, in 2D and 3D cases, it is found that the employment of these quadrature rules via tensor product simultaneously for the mass and stiffness matrix integrations of Lobatto elements produces a unified superconvergent formulation for the eigenvalue or frequency computation without wave propagation direction dependence, which usually is a critical issue for the multidimensional higher order mass matrix formulation. Consequently the proposed approach is capable of computing arbitrary frequencies in a superconvergent fashion. Meanwhile, numerical implementation of the proposed method for multidimensional problems is trivial. The effectiveness of the proposed methodology is systematically demonstrated by a series of numerical examples. Numerical results revealed that a superconvergence with 2(p+1)th order of frequency accuracy is achieved by the present unified formulation for the pth order Lobatto element.
Output field-quadrature measurements and squeezing in ultrastrong cavity-QED
Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco
2016-12-01
We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.
High efficiency second-harmonic generation in multi-pass quadrature arrangement
Kiriyama, Hiromitsu; Nakano, Fumihiko; Yamakawa, Koichi [Japan Atomic Energy Research Institute, Kansai Research Establishment, Kizu, Kyoto (Japan)
2001-05-01
We report on multi-pass quadrature frequency conversion of high-energy and high-average-power lasers with high conversion efficiency for pumping high peak power, ultrashort pulse Ti:sapphire laser amplifiers. Using a four-pass quadrature second harmonic scheme with KTiOPO{sub 4} (KTP) crystals, we obtained an efficiency from a fundamental laser energy into a total second-harmonic laser energy in excess of 80% of a commercial Q-Switched 1064-nm Nd:YAG laser at a low input fundamental laser intensity of 76 MW/cm{sup 2}. For higher power operation, we employed a two-pass quadrature scheme with CsLiB{sub 6}O{sub 10} (CLBO) crystals. We obtained a total second-harmonic output pulse energy of 2.73 J from an input 1064-nm fundamental pulse energy of 3.27 J of a custom-built Q-switched 1064-nm Nd:YAG laser system at a fundamental laser intensity of 330 MW/cm{sup 2} at 10 Hz, corresponding to energy conversion efficiency of 83%. We discuss the details of the design and performance of this frequency conversion scheme in terms of output energy, conversion efficiency and scalability. (author)
An anti-image interference quadrature IF architecture for satellite receivers
He Weidong
2014-08-01
Full Text Available Since Global Navigation Satellite System (GNSS signals span a wide range of frequency, wireless signals coming from other communication systems may be aliased and appear as image interference. In quadrature intermediate frequency (IF receivers, image aliasing due to in-phase and quadrature (I/Q channel mismatches is always a big problem. I/Q mismatches occur because of gain and phase imbalances between quadrature mixers and capacitor mismatches in analog-to-digital converters (ADC. As a result, the dynamic range and performance of a receiver are severely degraded. In this paper, several popular receiver architectures are summarized and the image aliasing problem is investigated in detail. Based on this analysis, a low-IF architecture is proposed for a single-chip solution and a novel and feasible anti-image algorithm is investigated. With this anti-image digital processing, the image reject ratio (IRR can reach approximately above 50 dB, which relaxes image rejection specific in front-end circuit designs and allows cheap and highly flexible analog front-end solutions. Simulation and experimental data show that the anti-image algorithm can work effectively, robustly, and steadily.
An anti-image interference quadrature IF architecture for satellite receivers
He Weidong; Lu Xiaochun; He Chengyan; James Torley
2014-01-01
Since Global Navigation Satellite System (GNSS) signals span a wide range of frequency, wireless signals coming from other communication systems may be aliased and appear as image interference. In quadrature intermediate frequency (IF) receivers, image aliasing due to in-phase and quadrature (I/Q) channel mismatches is always a big problem. I/Q mismatches occur because of gain and phase imbalances between quadrature mixers and capacitor mismatches in ana-log-to-digital converters (ADC). As a result, the dynamic range and performance of a receiver are severely degraded. In this paper, several popular receiver architectures are summarized and the image aliasing problem is investigated in detail. Based on this analysis, a low-IF architecture is pro-posed for a single-chip solution and a novel and feasible anti-image algorithm is investigated. With this anti-image digital processing, the image reject ratio (IRR) can reach approximately above 50 dB, which relaxes image rejection specific in front-end circuit designs and allows cheap and highly flexible analog front-end solutions. Simulation and experimental data show that the anti-image algorithm can work effectively, robustly, and steadily.
2.5-D/3-D resistivity modelling in anisotropic media using Gaussian quadrature grids
Zhou, Bing; Greenhalgh, Mark; Greenhalgh, S. A.
2009-01-01
We present a new numerical scheme for 2.5-D/3-D direct current resistivity modelling in heterogeneous, anisotropic media. This method, named the `Gaussian quadrature grid' (GQG) method, cooperatively combines the solution of the Variational Principle of the partial differential equation, Gaussian quadrature abscissae and local cardinal functions so that it has the main advantages of the spectral element method. The formulation shows that the GQG method is a modification of the spectral element method but does not employ the constant elements or require the mesh generator to match the Earth's surface. This makes it much easier to deal with geological models having a 2-D/3-D complex topography than using traditional numerical methods. The GQG technique can achieve a similar convergence rate to the spectral element method. We show it transforms the 2.5-D/3-D resistivity modelling problem into a sparse and symmetric linear equation system that can be solved by an iterative or matrix inversion method. Comparison with analytic solutions for homogeneous isotropic and anisotropic models shows that the error depends on the Gaussian quadrature order (abscissa number) and the subdomain size. The higher the order or the smaller the subdomain size that is employed, the more accurate are the results obtained. Several other synthetic examples, both homogeneous and inhomogeneous, incorporating sloping, undulating and severe topography, are presented and found to yield results comparable to finite element solutions involving a dense mesh.
Method to VCO Linearization for FMCW Radar%一种FMCW雷达中的VCO非线性矫正方法
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.
7～11GHz CMOS环形压控振荡器的设计%Design of a 7-11 GHz Ring VCO Based on CMOS Process
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.
One point quadrature shell elements: a study on convergence and patch tests
Cardoso, Rui P. R.; Yoon, Jeong-Whan
2007-10-01
One point quadrature shell elements are being widely used in the numerical simulation of shell structures, including sheet forming, because essentially of their computational efficiency. Nowadays, the purpose of using one point quadrature shell elements is not only related to computational efficiency but also because these elements have shown to be simultaneously robust and accurate in the simulation of complex sheet metal forming processes. The main objective of this work is to study the convergence behavior of different one-point quadrature shell elements and their ability to pass the membrane and bending patch tests. For comparison purposes, two new elements include a new formulation for the membrane strain field in order to further improve the membrane behavior of the element developed in previous work of (in Cardoso et al. Comput Meth Appl Mech Eng 191:5177, 2002). The original convective membrane strains of Cardoso et al. (Comput Meth Appl Mech Eng 191:5177, 2002) (in the stabilization matrices only) are thus replaced by new membrane strains, constructed directly at the co-rotational coordinate system (located at the element’s center). It is thus proved that with this new membrane formulation the elements pass now all the patch tests but, for warped (or curved) element geometries, their accuracy is not as good as the original element of (Cardoso et al. in Comput Meth Appl Mech Eng 191:5177, 2002) based on the convective coordinate system. In the numerical results presented in this paper, comprehensive comparison and discussion of these formulations are made for well known linear benchmark examples.
F. P. Santos
2013-09-01
Full Text Available Direct-quadrature generalized moment based methods were analysed in terms of accuracy, computational cost and robustness for the solution of the population balance problems in the [0,∞ and [0,1] domains. The minimum condition number of the coefficient matrix of their linear system of equations was obtained by global optimization. An heuristic scaling rule from the literature was also evaluated. The results indicate that the methods based on Legendre generalized moments are the most robust for the finite domain problems, while the DQMoM formulation that solves for the abscissas and weights using the heuristic scaling rule is the best for the infinite domain problems.
Thoudam Roshan
2016-10-01
Full Text Available Numerical solutions of the coupled Klein-Gordon-Schrödinger equations is obtained by using differential quadrature methods based on polynomials and quintic B-spline functions for space discretization and Runge-Kutta fourth order for time discretization. Stability of the schemes are studied using matrix stability analysis. The accuracy and efficiency of the methods are shown by conducting some numerical experiments on test problems. The motion of single soliton and interaction of two solitons are simulated by the proposed methods.
Entangling different degrees of freedom by quadrature squeezing cylindrically polarized modes
Gabriel, C.; Aiello, A.; Zhong, W.
2011-01-01
for intense beams of light by exploiting the properties of cylindrically polarized modes. We show that already in a classical picture the spatial and polarization field variables of these modes cannot be factorized. Theoretically it is proven that by quadrature squeezing cylindrically polarized modes one...... generates entanglement between these two different degrees of freedom. Experimentally we demonstrate amplitude squeezing of an azimuthally polarized mode by exploiting the nonlinear Kerr effect in a specially tailored photonic crystal fiber. These results display that such novel continuous...
Free Vibration Analysis of Sectorial Plates Using the Triangular Differential Quadrature Method
李欣; 钟宏志; 何玉红
2004-01-01
The triangular differential quadrature method was used to analyze the free vibrations of moderately thick sectorial plates. A triangular serendipity transformation was introduced to map the sectorial domain onto a unit isosceles right triangle. The first six non-dimensional frequencies of the sectorial plates were obtained for various combinations of clamped and simply supported boundary conditions. For sectorial plates with simply supported radial edges, the present results agree well with the available exact solutions and finite element solutions, demonstrating the effectiveness of the method.
Optimization of quadrature signal processing for laser interferometers for demanding applications
PodŻorny, Tomasz; Budzyń, Grzegorz; Tkaczyk, Jakub
2016-06-01
Presented paper performs an analysis of quadrature signal processing algorithms for high demanding laser interferometry applications. Careful signal processing is required to minimize nonlinearities which come from optical path and components' imperfections, and reduce overall instrumental error. Paper focuses on algebraic fits, because implementation for real time systems was a main requirement. The most demanding applications are stationary measurements where the position slightly fluctuates in the range below one fringe period. Therefore, analysis was performed for samples that were spread along a few milliradians of a full circle.
Semi-blind Adaptive Beamforming for High-throughput Quadrature Amplitude Modulation Systems
Sheng Chen; Wang Yao; Lajos Hanzo
2010-01-01
A semi-blind adaptive beamforming scheme is proposed for wireless systems that employ high-throughput quadrature amplitude modulation signalling. A minimum number of training symbols, equal to the number of receiver antenna array's elements, are first utilised to provide a rough initial least squares estimate of the beamformer's weight vector. A concurrent constant modulus algorithm and soft decision-directed scheme is then applied to adapt the beamformer. This semi-blind adaptive beamforming scheme is capable of converging fast to the minimum mean-square-error beamforming solution, as demonstrated in our simulation study.
A Synthetic Quadrature Phase Detector/Demodulator for Fourier Transform Transform Spectrometers
Campbell, Joel
2008-01-01
A method is developed to demodulate (velocity correct) Fourier transform spectrometer (FTS) data that is taken with an analog to digital converter that digitizes equally spaced in time. This method makes it possible to use simple low cost, high resolution audio digitizers to record high quality data without the need for an event timer or quadrature laser hardware, and makes it possible to use a metrology laser of any wavelength. The reduced parts count and simplicity implementation makes it an attractive alternative in space based applications when compared to previous methods such as the Brault algorithm.
M. Raghunadh Acharya
2009-12-01
Full Text Available A new quadrature formula has been proposed which uses modified weight functions derived from those of ‘Bernstein Polynomial’ using a ‘Two-Phase Modification’ therein. The quadrature formula has been compared empirically with the simple method of numerical integration using the well-known “Bernstein Operator”. The percentage absolute relative errors for the proposed quadrature formula and that with the “Bernstein Operator” have been computed for certain selected functions, with different number of usual equidistant node-points in the interval of integration~ [0, 1]. It has been observed that both of the proposed modified quadrature formulae, respectively after the ‘Phase-I’ and after the ‘Phases-I & II’ of these modifications, produce significantly better results than that using, simply, the “Bernstein Operator”. Inasmuch as the proposed “Two-Phase Improvement” is available iteratively again-and-again at the end of the current iteration, the proposed improvement algorithm, which is ‘Computerizable’, is an “Iterative-Algorithm”, leading to more-and-more efficient “Quadrature-Operator”, till we are pleased!
Cui, Junning; He, Zhangqiang; Tan, Jiubin; Sun, Tao
2016-10-03
The deviation of wave plates' optical axes from their intended angles, which may result from either instability or assembly error, is the main cause of quadrature phase error in homodyne quadrature laser interferometers (HQLIs). The quadrature phase error sensitivity to wave plate angle deviations, which is an effective measure of HQLI robustness, is further amplified by beam splitter imperfections. In this paper, a new HQLI design involving non-polarization beam splitting is presented, and a method of making this HQLI robust by yawing the wave plates in the measurement and reference arms is proposed. The theoretical analysis results indicate that ultra-low quadrature phase error sensitivities to wave plate angle deviations can be realized and that non-polarizing beam splitter imperfections can be adequately compensated for. The experimental results demonstrate that the proposed method can reduce the quadrature phase error sensitivity by more than 1 order of magnitude, from a theoretical value of 1.4°/1° to 0.05°/1°.
Ferro-based derivatizing agents for LC/MS an LC/EC/MS
Seiwert, Bettina
2007-01-01
Within this thesis, the development and application of ferrocene-based derivatizing agents for LC/MS and LC/EC/MS is presented. The advantages of derivatization by ferrocenes are the similtaneous introduction of a mass tag and an electroactive group, which make them ideally suited for LC/MS and esp
A class-C VCO based Σ-Δ fraction-N frequency synthesizer with AFC for 802.11ah applications
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.
Goldstein, M; Haussmann, W; Hayman, W; Rogge, L
1992-01-01
This volume consists of the proceedings of the NATO Advanced Research Workshop on Approximation by Solutions of Partial Differential Equations, Quadrature Formulae, and Related Topics, which was held at Hanstholm, Denmark. These proceedings include the main invited talks and contributed papers given during the workshop. The aim of these lectures was to present a selection of results of the latest research in the field. In addition to covering topics in approximation by solutions of partial differential equations and quadrature formulae, this volume is also concerned with related areas, such as Gaussian quadratures, the Pompelu problem, rational approximation to the Fresnel integral, boundary correspondence of univalent harmonic mappings, the application of the Hilbert transform in two dimensional aerodynamics, finely open sets in the limit set of a finitely generated Kleinian group, scattering theory, harmonic and maximal measures for rational functions and the solution of the classical Dirichlet problem. In ...
Coherent Detection of Optical Quadrature Phase-Shift Keying Signals With Carrier Phase Estimation
Ly-Gagnon, Dany-Sebastien; Tsukamoto, Satoshi; Katoh, Kazuhiro; Kikuchi, Kazuro
2006-01-01
This paper describes a coherent optical receiver for demodulating optical quadrature phase-shift keying (QPSK) signals. At the receiver, a phase-diversity homodyne detection scheme is employed without locking the phase of the local oscillator (LO). To handle the carrier phase drift, the carrier phase is estimated with digital signal processing (DSP) on the homodyne-detected signal. Such a scheme presents the following major advantages over the conventional optical differential detection. First, its bit error rate (BER) performance is better than that of differential detection. This higher sensitivity can extend the reach of unrepeated transmission systems and reduce crosstalk between multiwavelength channels. Second, the optoelectronic conversion process is linear, so that the whole optical signal information can be postprocessed in the electrical domain. Third, this scheme is applicable to multilevel modulation formats such as M-array PSK and quadrature amplitude modulation (QAM). The performance of the receiver is evaluated through various simulations and experiments. As a result, an unrepeated transmission over 210 km with a 20-Gb/s optical QPSK signal is achieved. Moreover, in wavelength-division multiplexing (WDM) environment, coherent detection allows the filtering of a desired wavelength channel to reside entirely in the electrical domain, taking advantage of the sharp cutoff characteristics of electrical filters. The experiments show the feasibility to transmit polarization-multiplexed 40-Gb/s QPSK signals over 200 km with channel spacing of 16 GHz, leading to a spectral efficiency as high as 2.5 b/s/Hz.
Den Satipar
2017-01-01
Full Text Available A new configuration of voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator employs two voltage differencing current conveyors (VDCCs, two resistors, and two grounded capacitors. In this design, the use of multiple/dual output terminal active building block is not required. The tuning of frequency of oscillation (FO can be done electronically by adjusting the bias current of active device without affecting condition of oscillation (CO. The electronic tuning can be done by controlling the bias current using a digital circuit. The amplitude of two sinusoidal outputs is equal when the frequency of oscillation is tuned. This makes the sinusoidal output voltages meet good total harmonic distortions (THD. Moreover, the proposed circuit can provide the sinusoidal output current with high impedance which is connected to external load or to another circuit without the use of buffer device. To confirm that the oscillator can generate the quadrature sinusoidal output signal, the experimental results using VDCC constructed from commercially available ICs are also included. The experimental results agree well with theoretical anticipation.
Nicola Ponara
2012-11-01
Full Text Available Regularized Heaviside and Dirac delta function are used in several fields of computational physics and mechanics. Hence the issue of the quadrature of integrals of discontinuous and singular functions arises. In order to avoid ad-hoc quadrature procedures, regularization of the discontinuous and the singular fields is often carried out. In particular, weight functions of the signed distance with respect to the discontinuity interface are exploited. Tornberg and Engquist (Journal of Scientific Computing, 2003, 19: 527–552 proved that the use of compact support weight function is not suitable because it leads to errors that do not vanish for decreasing mesh size. They proposed the adoption of non-compact support weight functions. In the present contribution, the relationship between the Fourier transform of the weight functions and the accuracy of the regularization procedure is exploited. The proposed regularized approach was implemented in the eXtended Finite Element Method. As a three-dimensional example, we study a slender solid characterized by an inclined interface across which the displacement is discontinuous. The accuracy is evaluated for varying position of the discontinuity interfaces with respect to the underlying mesh. A procedure for the choice of the regularization parameters is proposed.
B. Kuldeep
2015-06-01
Full Text Available Fractional calculus has recently been identified as a very important mathematical tool in the field of signal processing. Digital filters designed by fractional derivatives give more accurate frequency response in the prescribed frequency region. Digital filters are most important part of multi-rate filter bank systems. In this paper, an improved method based on fractional derivative constraints is presented for the design of two-channel quadrature mirror filter (QMF bank. The design problem is formulated as minimization of L2 error of filter bank transfer function in passband, stopband interval and at quadrature frequency, and then Lagrange multiplier method with fractional derivative constraints is applied to solve it. The proposed method is then successfully applied for the design of two-channel QMF bank with higher order filter taps. Performance of the QMF bank design is then examined through study of various parameters such as passband error, stopband error, transition band error, peak reconstruction error (PRE, stopband attenuation (As. It is found that, the good design can be obtained with the change of number and value of fractional derivative constraint coefficients.
Shoupeng, Song; Zhou, Jiang
2017-03-01
Converting ultrasonic signal to ultrasonic pulse stream is the key step of finite rate of innovation (FRI) sparse sampling. At present, ultrasonic pulse-stream-forming techniques are mainly based on digital algorithms. No hardware circuit that can achieve it has been reported. This paper proposes a new quadrature demodulation (QD) based circuit implementation method for forming an ultrasonic pulse stream. Elaborating on FRI sparse sampling theory, the process of ultrasonic signal is explained, followed by a discussion and analysis of ultrasonic pulse-stream-forming methods. In contrast to ultrasonic signal envelope extracting techniques, a quadrature demodulation method (QDM) is proposed. Simulation experiments were performed to determine its performance at various signal-to-noise ratios (SNRs). The circuit was then designed, with mixing module, oscillator, low pass filter (LPF), and root of square sum module. Finally, application experiments were carried out on pipeline sample ultrasonic flaw testing. The experimental results indicate that the QDM can accurately convert ultrasonic signal to ultrasonic pulse stream, and reverse the original signal information, such as pulse width, amplitude, and time of arrival. This technique lays the foundation for ultrasonic signal FRI sparse sampling directly with hardware circuitry.
A quadrature based method of moments for nonlinear Fokker-Planck equations
Otten, Dustin L.; Vedula, Prakash
2011-09-01
Fokker-Planck equations which are nonlinear with respect to their probability densities and occur in many nonequilibrium systems relevant to mean field interaction models, plasmas, fermions and bosons can be challenging to solve numerically. To address some underlying challenges, we propose the application of the direct quadrature based method of moments (DQMOM) for efficient and accurate determination of transient (and stationary) solutions of nonlinear Fokker-Planck equations (NLFPEs). In DQMOM, probability density (or other distribution) functions are represented using a finite collection of Dirac delta functions, characterized by quadrature weights and locations (or abscissas) that are determined based on constraints due to evolution of generalized moments. Three particular examples of nonlinear Fokker-Planck equations considered in this paper include descriptions of: (i) the Shimizu-Yamada model, (ii) the Desai-Zwanzig model (both of which have been developed as models of muscular contraction) and (iii) fermions and bosons. Results based on DQMOM, for the transient and stationary solutions of the nonlinear Fokker-Planck equations, have been found to be in good agreement with other available analytical and numerical approaches. It is also shown that approximate reconstruction of the underlying probability density function from moments obtained from DQMOM can be satisfactorily achieved using a maximum entropy method.
Hasegawa, Takemitsu; Hibino, Susumu; Hosoda, Yohsuke; Ninomiya, Ichizo
2007-08-01
An improvement is made to an automatic quadrature due to Ninomiya (J. Inf. Process. 3:162?170, 1980) of adaptive type based on the Newton?Cotes rule by incorporating a doubly-adaptive algorithm due to Favati, Lotti and Romani (ACM Trans. Math. Softw. 17:207?217, 1991; ACM Trans. Math. Softw. 17:218?232, 1991). We compare the present method in performance with some others by using various test problems including Kahaner?s ones (Computation of numerical quadrature formulas. In: Rice, J.R. (ed.) Mathematical Software, 229?259. Academic, Orlando, FL, 1971).
Nguyen, Thach G; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J
2015-01-01
We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response.
LC-MS systems for quantitative bioanalysis.
van Dongen, William D; Niessen, Wilfried M A
2012-10-01
LC-MS has become the method-of-choice in small-molecule drug bioanalysis (molecular mass Triple quadrupole MS is the established bioanalytical technique due to its unpreceded selectivity and sensitivity, but high-resolution accurate-mass MS is recently gaining ground due to its ability to provide simultaneous quantitative and qualitative analysis of drugs and their metabolites. This article discusses current trends in the field of bioanalytical LC-MS (until September 2012), and provides an overview of currently available commercial triple quadrupole MS and high-resolution LC-MS instruments as applied for the bioanalysis of small-molecule and biopharmaceutical drugs.
LC Oscillator Driver for Safety Critical Applications
Horsky, Pavel
2011-01-01
A CMOS harmonic signal LC oscillator driver for automotive applications working in a harsh environment with high safety critical requirements is described. The driver can be used with a wide range of external components parameters (LC resonance network of a sensor). Quality factor of the external LC network can vary two decades. Amplitude regulation of the driver is digitally controlled and the DAC is constructed as exponential with piece-wise-linear (PWL) approximation. Low current consumption for high quality resonance networks is achieved. Realized oscillator is robust, used in safety critical application and has low EMC emissions.
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.
A LC Voltage-Controlled Oscillator Design and Simulation%低相位噪声压控振荡器的设计及仿真
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．
Khaleghi, Salman; Chitgarha, Mohammad Reza; Yilmaz, Omer F; Tur, Moshe; Haney, Michael W; Langrock, Carsten; Fejer, Martin M; Willner, Alan E
2013-05-15
We experimentally demonstrate a reconfigurable optical converter/encoder for quadrature amplitude modulated (QAM) signals. The system utilizes nonlinear wavelength multicasting, conversion-dispersion delays, and simultaneous nonlinear multiplexing and sampling. We show baud rate tunability (31 and 20 Gbaud) and reconfigurable conversions from lower-order QAM signals to higher-order QAM signals (e.g., 64-QAM).
Sokoya, O
2008-05-01
Full Text Available The performance analysis of high rate space–time trellis-coded modulation (HR-STTCM) using the Gauss–Chebyshev quadrature technique is presented. HR-STTCM is an example of space–time codes that combine the idea used in trellis coded modulation (TCM...
Shizgal, Bernie D.
2016-08-01
Nonclassical quadratures based on a new set of half-range polynomials, Tn(x) , orthogonal with respect to w(x) =e - x - b /√{ x } for x ∈ [ 0 , ∞) are employed in the efficient calculation of the nuclear fusion reaction rate coefficients from cross section data. The parameter b = B /√{kB T } in the weight function is temperature dependent and B is the Gamow factor. The polynomials Tn(x) satisfy a three term recurrence relation defined by two sets of recurrence coefficients, αn and βn. These recurrence coefficients define in turn the tridiagonal Jacobi matrix whose eigenvalues are the quadrature points and the weights are calculated from the first components of the eigenfunctions. For nonresonant nuclear reactions for which the astrophysical function can be expressed as a lower order polynomial in the relative energy, the convergence of the thermal average of the reactive cross section with this nonclassical quadrature is extremely rapid requiring in many cases 2-4 quadrature points. The results are compared with other libraries of nuclear reaction rate coefficient data reported in the literature.
Da Ros, Francesco; Marco Calabrese, Pachito; Kang, Ning;
2013-01-01
Phase-sensitive processes exploiting FWM in an HNLF allow simultaneously converting two orthogonal quadratures of an optical signal to different wavelengths. Conversion efficiencies to two 90°-phase-shifted idlers exceeding 10dB of phase-sensitive extinction ratio are obtained experimentally....
Barton, Michael
2016-03-14
We introduce optimal quadrature rules for spline spaces that are frequently used in Galerkin discretizations to build mass and stiffness matrices. Using the homotopy continuation concept (Bartoň and Calo, 2016) that transforms optimal quadrature rules from source spaces to target spaces, we derive optimal rules for splines defined on finite domains. Starting with the classical Gaussian quadrature for polynomials, which is an optimal rule for a discontinuous odd-degree space, we derive rules for target spaces of higher continuity. We further show how the homotopy methodology handles cases where the source and target rules require different numbers of optimal quadrature points. We demonstrate it by deriving optimal rules for various odd-degree spline spaces, particularly with non-uniform knot sequences and non-uniform multiplicities. We also discuss convergence of our rules to their asymptotic counterparts, that is, the analogues of the midpoint rule of Hughes et al. (2010), that are exact and optimal for infinite domains. For spaces of low continuities, we numerically show that the derived rules quickly converge to their asymptotic counterparts as the weights and nodes of a few boundary elements differ from the asymptotic values.
Electrostatic stiffness correction for quadrature error in decoupled dual-mass MEMS gyroscope
Li, Hongsheng; Cao, Huiliang; Ni, Yunfang
2014-07-01
This paper proposes an electrostatic stiffness correction method for the quadrature error (QUER) in a decoupled dual-mass gyroscope structure. The QUER is caused by the imperfections during the structure manufacturing process, and the two masses usually have different QUERs. The harm contribution to the Coriolis signal is analyzed and quantified. The generating forms of QUER motion in both masses are analyzed, the correction electrodes' working principle is introduced, and a single mass individual correction method is proposed. The QUER stiffness correction system is designed based on a PI controller, and the experiments are arranged to verify the theoretical analysis. The bias stability decreases from 2.06 to 0.64 deg/h after the QUER correction, and the parameters of scale factor such as nonlinearly, asymmetry, and repeatability, reduce from 143, 557, and 210 ppm to 84, 242, and 175 ppm, respectively.
Cigeroglu, Ender; Samandari, Hamed
2014-11-01
Nonlinear free vibration analysis of curved double-walled carbon nanotubes (DWNTs) embedded in an elastic medium is studied in this study. Nonlinearities considered are due to large deflection of carbon nanotubes (geometric nonlinearity) and nonlinear interlayer van der Waals forces between inner and outer tubes. The differential quadrature method (DQM) is utilized to discretize the partial differential equations of motion in spatial domain, which resulted in a nonlinear set of algebraic equations of motion. The effect of nonlinearities, different end conditions, initial curvature, and stiffness of the surrounding elastic medium, and vibrational modes on the nonlinear free vibration of DWCNTs is studied. Results show that it is possible to detect different vibration modes occurring at a single vibration frequency when CNTs vibrate in the out-of-phase vibration mode. Moreover, it is observed that boundary conditions have significant effect on the nonlinear natural frequencies of the DWCNT including multiple solutions.
Parallel-quadrature phase-shifting digital holographic microscopy using polarization beam splitter.
Das, Bhargab; Yelleswarapu, Chandra S; Rao, Dvgln
2012-11-01
We present a digital holography microscopy technique based on parallel-quadrature phase-shifting method. Two π/2 phase-shifted holograms are recorded simultaneously using polarization phase-shifting principle, slightly off-axis recording geometry, and two identical CCD sensors. The parallel phase-shifting is realized by combining circularly polarized object beam with a 45° degree polarized reference beam through a polarizing beam splitter. DC term is eliminated by subtracting the two holograms from each other and the object information is reconstructed after selecting the frequency spectrum of the real image. Both amplitude and phase object reconstruction results are presented. Simultaneous recording eliminates phase errors caused by mechanical vibrations and air turbulences. The slightly off-axis recording geometry with phase-shifting allows a much larger dimension of the spatial filter for reconstruction of the object information. This leads to better reconstruction capability than traditional off-axis holography.
Design of Novel Precise Quadrature Oscillators Employing ECCIIs with Electronic Control
SOTNER, R.
2013-05-01
Full Text Available In this paper, an interesting design of precise quadrature oscillator employing electronically controllable current conveyors of the second generation (ECCII is presented. The main purpose of this paper is to show advantages and features of direct electronic control of application by an adjustable current gain where help of signal flow graph approach was used to clearer and visual understanding of the design. The discussed circuit and its presented modification have several favorable features such as grounded capacitors, independent electronic adjusting of oscillation frequency and condition of oscillation by the current gain and easy automatic gain control circuit (AGC implementation (non-ideal effects of tuning process on output amplitudes are suppressed. Oscillator was designed for frequency band of units of MHz and tested with two types of inertial AGCs. Theoretical presumptions were confirmed by laboratory experiments.
李晶晶; 程昌钧
2004-01-01
Based on the Reddy' s theory of plates with the effect of higher-order shear deformations, the governing equations for bending of orthotropic plates with finite deformations were established. The differential quadrature ( DQ ) method of nonlinear analysis to the problem was presented. New DQ approach, presented by Wang and Bert (DQWB), is extended to handle the multiple boundary conditions of plates. The techniques were also further extended to simplify nonlinear computations. The numerical convergence and comparison of solutions were studied. The results show that the DQ method presented is very reliable and valid. Moreover, the influences of geometric and material parameters as well as the transverse shear deformations on nonlinear bending were investigated.Numerical results show the influence of the shear deformation on the static bending of orthotropic moderately thick plate is significant.
Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study
Solis S.E.
2012-01-01
Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.
WangLin; NiQiao; HuangYuying
2003-01-01
This paper proposes a new method for investigating the Hopf bifurcation of a curved pipe conveying fluid with nonlinear spring support. The nonlinear equation of motion is derived by forces equilibrium on microelement of the system under consideration. The spatial coordinate of the system is discretized by the differential quadrature method and then the dynamic equation is solved by the Newton-Raphson method. The numerical solutions show that the inner fluid velocity of the Hopf bifurcation point of the curved pipe varies with different values of the parameter,nonlinear spring stiffness. Based on this, the cycle and divergent motions are both found to exist at specific fluid flow velocities with a given value of the nonlinear spring stiffness. The results are useful for further study of the nonlinear dynamic mechanism of the curved fluid conveying pipe.
Phase quadrature discrimination based on three-pump four-wave mixing in nonlinear optical fibers.
Baillot, Maxime; Gay, Mathilde; Peucheret, Christophe; Michel, Joindot; Chartier, Thierry
2016-11-14
We theoretically and experimentally study the principle of phase-sensitive frequency conversion in a highly-nonlinear fiber using three pump waves. This mechanism, originally demonstrated with four continuous-wave pumps and a signal wave, is based on four-wave mixing and enables to convert the two quadrature components of the signal to different frequencies. In this work, we derive a set of two simple equations to describe this mechanism and find analytic solutions. We show that only three pumps are required, instead of four as originally proposed. We give simple relations to determine the initial conditions for the power levels and the phases of the pumps. To validate this approach, we perform an experimental demonstration of the three-pump scheme and find excellent agreement with the theory.
Rivera-Ortega, Uriel; Meneses-Fabian, Cruz; Rodriguez-Zurita, Gustavo; Robledo-Sanchez, Carlos
2014-04-01
An alternative method for phase retrieval based on spatial and binary non-quadrature amplitude modulation (NQAM) is presented. This proposal is based on the superposition of a probe beam with a reference beam modulated in phase and amplitude (PAM) by NQAM, which is implemented by two neutral density filters (NDF) in a three-beam Mach-Zehnder interferometer (MZI). The principal advantage of this proposal lies in an analytical relationship between the variations of phase and visibility in an interferogram with the variations in the amplitudes of the reference beams used to implement NQAM; thus, the interferograms can be normalized and their introduced phase variations can be known from the measured intensities. Consequently it is possible to successfully retrieve the object phase. It is worthy to note that this method is capable of accepting that the phase and visibility variations in the interferograms could be spatial functions.
Utilizing Gauss-Hermite Quadrature to Evaluate Uncertainty in Dynamic System Response
Field, R.V.; Paez, T.L.; Red-Horse, J.R.
1998-11-17
Probabilistic uncertainty is a phenomenon that occurs to a certain degree in many engineering!~ applications. The effects that the uncertainty has upon a given system response is a matter of some concern. Techniques which provide insight to these effects will be required as modeling and prediction become a more vital tool in the engineering design process. As might be expected, this is a difficult proposition and the focus of many research efforts. The purpose of this paper is to outline a procedure to evaluate uncertainty in dynamic system response exploiting Gauss-Hermite numerical quadrature. Specifically numerical integration techniques are utilized in conjunction with the Advanced Mean Value method to efficiently and accurately estimate moments of the response process. A numerical example illustrating the use of this analytical tool in a practical framework is presented.
Hadjesfandiari, Ali R
2010-01-01
A boundary element formulation is developed to determine the complex stress intensity factors associated with cracks on the interface between dissimilar materials. This represents an extension of the methodology developed previously by the authors for determination of free-edge generalized stress intensity factors on bi-material interfaces, which employs displacements and weighted tractions as primary variables. However, in the present work, the characteristic oscillating stress singularity is addressed through the introduction of complex weighting functions for both displacements and tractions, along with corresponding non-standard numerical quadrature formulas. As a result, this boundary-only approach provides extremely accurate mesh-independent solutions for a range of two-dimensional interface crack problems. A number of computational examples are considered to assess the performance of the method in comparison with analytical solutions and previous work on the subject. As a final application, the method ...
Utilizing Gauss-Hermite Quadrature to Evaluate Uncertainty in Dynamic System Response
Field, R.V.; Paez, T.L.; Red-Horse, J.R.
1998-11-17
Probabilistic uncertainty is a phenomenon that occurs to a certain degree in many engineering!~ applications. The effects that the uncertainty has upon a given system response is a matter of some concern. Techniques which provide insight to these effects will be required as modeling and prediction become a more vital tool in the engineering design process. As might be expected, this is a difficult proposition and the focus of many research efforts. The purpose of this paper is to outline a procedure to evaluate uncertainty in dynamic system response exploiting Gauss-Hermite numerical quadrature. Specifically numerical integration techniques are utilized in conjunction with the Advanced Mean Value method to efficiently and accurately estimate moments of the response process. A numerical example illustrating the use of this analytical tool in a practical framework is presented.
Performance of quadrature overlapped raised-cosine modulation over nonlinear satellite channels
Divsalar, D.; Simon, M. K.
1981-01-01
This paper considers the performance evaluation of Staggered Quadrature Overlapped Raised Cosine (SQORC) signal transmission through wideband nonlinear satellite channels in the presence of uplink and downlink additive Gaussian noise. Expressions for the bit error rate are derived for a general transponder model with AM-AM and AM-PM conversion. It is shown that the bit error rate of SQORC is one-half of the sum of the bit error rate of MSK at 2/3 of the uplink signal-to-noise ratio and the bit error rate of Quadriphase Phase-Shift Keying QPSK at 4/3 of the uplink signal-to-noise ratio, whereas the spectrum of SQROC is the product of MSK and QPSK spectra. Numerical results are presented for a transponder which is modelled as a hard limiter.
Security of Quantum-Readout PUFs against Quadrature-Based Challenge-Estimation Attacks
Škorić, Boris; Mosk, Allard P.; Pinkse, Pepijn W. H.
2013-08-01
The concept of quantum-secure readout of Physical Unclonable Functions (PUFs) has recently been realized experimentally in an optical PUF system. We analyze the security of this system under the strongest type of classical attack: the challenge estimation attack. The adversary performs a measurement on the challenge quantum state in order to learn as much about it as he can. Using this knowledge, he then tries to reconstruct the challenge and to emulate the PUF. We consider quadrature measurements, which are the most informative practical measurements known to us. We prove that even under this attack the expected number of photons detected in the verification mechanism is approximately a factor S + 1 too low; here S is the Quantum Security Parameter, defined as the number of modes in the optical system divided by the number of photons in the challenge. The photon count allows for a reliable distinction between an authentic PUF and a challenge estimation attack.
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.
基于Verilog-A行为描述模型的VCO设计%Design of VCO based behavioral model using Verilog-A
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.
Integrated VCOs for Medical Implant Transceivers
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.
Sanchez G, J., E-mail: julian.sanchez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)
2015-09-15
The solution of the so-called Canonical problems of neutron transport theory has been given by Case, who developed a method akin to the classical eigenfunction expansion procedure, extended to admit singular eigenfunctions. The solution is given as a set consisting of a Fredholm integral equation coupled with a transcendental equation, which has to be solved for the expansion coefficients by iteration. CASE's method make extensive use of the results of the theory of functions of a complex variable and many successful approaches to solve in an approximate form the above mentioned set have been reported in the literature. We present here an entirely different approach which deals with the canonical problems in a more direct and elementary manner. As far as we know, the original idea for the latter method is due to Carlvik who devised the escape probability approximation to the solution of the neutron transport equation in its integral form. In essence, the procedure consists in assuming a sectionally constant form of the neutron density that in turn yields a set of linear algebraic equations obeyed by the assumed constant values of the density. Very well established techniques of numerical analysis for the solution of integral equations consist in independent approaches that generalize the sectionally constant approach by assuming a sectionally low degree polynomial for the unknown function. This procedure also known as the arbitrary quadratures method is especially suited to deal with cases where the kernel of the integral equation is singular. The author wishes to present the results obtained with the arbitrary quadratures method for the numerical calculation of the monoenergetic neutron density in a critical, homogeneous sphere of finite radius with isotropic scattering. The singular integral equation obeyed by the neutron density in the critical sphere is introduced, an outline of the method's main features is given, and tables and graphs of the density
Ambruş, Victor Eugen; Sofonea, Victor
2014-04-01
The Gauss-Laguerre quadrature method is used on the Cartesian semiaxes in the momentum space to construct a family of lattice Boltzmann models. When all quadrature orders Qx, Qy, Qz equal N+1, the Laguerre lattice Boltzmann model LLB(Qx,Qy,Qz) exactly recovers all moments up to order N of the Maxwell-Boltzmann equilibrium distribution function f(eq), calculated over any Cartesian octant of the three-dimensional momentum space. Results of Couette flow simulations at Kn=0.1, 0.5, 1.0 and in the ballistic regime are reported. Specific microfluidic effects (velocity slip, temperature jump, longitudinal heat flux) are well captured up to Kn=0.5, as demonstrated by comparison to direct simulation Monte Carlo results. Excellent agreement with analytic results is obtained in the ballistic regime.
Golestan, Saeed; Guerrero, Josep M.; Abusorrah, Abdullah
2017-01-01
The quadrature signal generation based phase-locked loops (QSG-PLLs) are highly popular for synchronization purposes in single-phase systems. The main difference among these PLLs often lies in the technique they use for creating the fictitious quadrature component. One of the easiest QSG approaches...... is delaying the original single-phase signal by a quarter of a cycle. The PLL with such QSG technique is often called the transfer delay based PLL (TD-PLL). The TD-PLL benefits from a simple structure, rather fast dynamic response, and a good detection accuracy when the grid frequency is at its nominal value......, but it suffers from a phase offset error and double frequency oscillatory error in the estimated phase and frequency in the presence of frequency drifts. In this paper, a simple yet effective approach to remove the aforementioned errors of the TD-PLL is proposed. The resultant PLL structure is called...
Friedberg, R; Zhao Wei Qin
2000-01-01
We present a new method to derive low-lying N-dimensional quantum wave functions by quadrature along a single trajectory. The N-dimensional Schroedinger equation is cast into a series of readily integrable first order ordinary differential equations. Our approach resembles the familiar W.K.B. approximation in one dimension, but is designed to explore the classically forbidden region and has a much wider applicability than W.K.B.. The method also provides a perturbation series expansion and the Green's functions of the wave equation in N-dimension, all by quadratures along a single trajectory. A number of examples are given for illustration, including a simple algorithm to evaluate the Stark effect in closed form to any finite order of the electric field.
H. S. Shukla
2015-01-01
Full Text Available In this paper, a modified cubic B-spline differential quadrature method (MCB-DQM is employed for the numerical simulation of two-space dimensional nonlinear sine-Gordon equation with appropriate initial and boundary conditions. The modified cubic B-spline works as a basis function in the differential quadrature method to compute the weighting coefficients. Accordingly, two dimensional sine-Gordon equation is transformed into a system of second order ordinary differential equations (ODEs. The resultant system of ODEs is solved by employing an optimal five stage and fourth-order strong stability preserving Runge–Kutta scheme (SSP-RK54. Numerical simulation is discussed for both damped and undamped cases. Computational results are found to be in good agreement with the exact solution and other numerical results available in the literature.
H. S. Shukla
2014-11-01
Full Text Available In this paper, a numerical solution of two dimensional nonlinear coupled viscous Burger equation is discussed with appropriate initial and boundary conditions using the modified cubic B-spline differential quadrature method. In this method, the weighting coefficients are computed using the modified cubic B-spline as a basis function in the differential quadrature method. Thus, the coupled Burger equation is reduced into a system of ordinary differential equations. An optimal five stage and fourth-order strong stability preserving Runge–Kutta scheme is applied for solving the resulting system of ordinary differential equations. The accuracy of the scheme is illustrated by taking two numerical examples. Computed results are compared with the exact solutions and other results available in literature. Obtained numerical result shows that the described method is efficient and reliable scheme for solving two dimensional coupled viscous Burger equation.
Clark, William A. (Inventor); Juneau, Thor N. (Inventor); Lemkin, Mark A. (Inventor); Roessig, Allen W. (Inventor)
2001-01-01
A microfabricated vibratory rate gyroscope to measure rotation includes two proof-masses mounted in a suspension system anchored to a substrate. The suspension has two principal modes of compliance, one of which is driven into oscillation. The driven oscillation combined with rotation of the substrate about an axis perpendicular to the substrate results in Coriolis acceleration along the other mode of compliance, the sense-mode. The sense-mode is designed to respond to Coriolis accelerationwhile suppressing the response to translational acceleration. This is accomplished using one or more rigid levers connecting the two proof-masses. The lever allows the proof-masses to move in opposite directions in response to Coriolis acceleration. The invention includes a means for canceling errors, termed quadrature error, due to imperfections in implementation of the sensor. Quadrature-error cancellation utilizes electrostatic forces to cancel out undesired sense-axis motion in phase with drive-mode position.
Caves, C. M.; Schumaker, B. L.
1985-01-01
A new formalism for analyzing two-photon devices, such as parametric amplifiers and phase-conjugate mirrors, is proposed in part I, focusing on the properties and the significance of the quadrature-phase amplitudes and two-mode squeezed states. Time-stationary quasi-probability noise is also detailed for the case of Gaussian noise, and uncertainty principles for the quadrature-phase amplitudes are outlined, as well as some important properties of the two-mode states. Part II establishes a mathematical foundation for the formalism, with introduction of a vector notation for compact representation of two-mode properties. Fundamental unitary operators and special quantum states are also examined with an emphasis on the two-mode squeezed states. The results are applied to a previously studied degenerate limit (epsilon = 0).
Voss, P L; Kumar, P; Voss, Paul L.; K\\"{o}pr\\"{u}l\\"{u}, Kahraman G.; Kumar, Prem
2004-01-01
We present a quantum theory of nondegenerate phase-sensitive parametric amplification in a $\\chi^{(3)}$ nonlinear medium. The non-zero response time of the Kerr $(\\chi^{(3)})$ nonlinearity determines the quantum-limited noise figure of $\\chi^{(3)}$ parametric amplification, as well as the limit on quadrature squeezing. This non-zero response time of the nonlinearity requires coupling of the parametric process to a molecular-vibration phonon bath, causing the addition of excess noise through spontaneous Raman scattering. We present analytical expressions for the quantum-limited noise figure of frequency non-degenerate and frequency degenerate $\\chi^{(3)}$ parametric amplifiers operated as phase-sensitive amplifiers. We also present results for frequency non-degenerate quadrature squeezing. We show that our non-degenerate squeezing theory agrees with the degenerate squeezing theory of Boivin and Shapiro as degeneracy is approached. We have also included the effect of linear loss on the phase-sensitive process.
A contribution to continuous-time quadrature bandpass sigma-delta modulators for low-IF receivers
Kim, Song-Bok
2009-01-01
This work presents the implementation of the continuous-time quadrature bandpass sigma-delta modulators (CT-QBP SDMs). CT-QBP SDMs is well suited for low-IF receivers due to some significant advantages over other implementations. Firstly, the possible design methodologies have been defined and compared. The proposed inverse method is desirable for the design of CT-QBP SDM. Starting from CT loop filter optimization, the equivalent noise shaping transfer function is finally calculated and its s...
Truszczynski, T
This thesis presents the author’s work during the internship at the European Laboratory for Particle Physics (CERN). The quadrature frequency converter is one of the modules that has been developed to upgrade the Proton Synchrotron RF system. Basic information about accelerators, fundamentals of IQ signal representation, mixing and phase shifting techniques are introduced. The development process of the converter is presented with the design details and measurements of the prototype board.
Spectral Gauss quadrature method with subspace interpolation for Kohn-Sham Density functional theory
Wang, Xin
Algorithms with linear-scaling ( (N)) computational complexity for Kohn-Sham density functional theory (K-S DFT) is crucial for studying molecular systems beyond thousands of atoms. Of the (N) methods that use a polynomial-based approximation of the density matrix, the linear-scaling spectral Gauss quadrature (LSSGQ) method (Suryanarayana et al., JMPS, 2013) has been shown to exhibit the fastest convergence. The LSSGQ method requires a Lanczos procedure at every node in a real-space mesh, leading to a large computational pre-factor. We propose a new interpolation scheme specific to the LSSGQ method that lift the need to perform a Lanczos procedure at every node in the real-mesh. This interpolation will be referred to as subspace interpolation. The key idea behind subspace interpolation is that there is a large overlap in the Krylov-subspaces produced by the Lanczos procedures of nodes that are close in real-space. The subspace interpolation scheme takes advantage of the block-Lanczos procedure to group the Krylov-subspaces from a few representative nodes to approximate the density matrix over a large collection of nodes. Subspace interpolation outperforms cubic-spline interpolation by several orders of magnitude.
Digital services using quadrature amplitude modulation (QAM) over CATV analog DWDM system
Yeh, JengRong; Selker, Mark D.; Trail, J.; Piehler, David; Levi, Israel
2000-04-01
Dense Wavelength Division Multiplexing (DWDM) has recently gained great popularity as it provides a cost effective way to increase the transmission capacity of the existing fiber cable plant. For a long time, Dense WDM was exclusively used for baseband digital applications, predominantly in terrestrial long haul networks and in some cases in metropolitan and enterprise networks. Recently, the performance of DWDM components and frequency-stabilized lasers has substantially improved while the costs have down significantly. This makes a variety of new optical network architectures economically viable. The first commercial 8- wavelength DWDM system designed for Hybrid Fiber Coax networks was reported in 1998. This type of DWDM system utilizes Sub-Carrier Multiplexing (SCM) of Quadrature Amplitude Modulated (QAM) signals to transport IP data digital video broadcast and Video on Demand on ITU grid lightwave carriers. The ability of DWDM to provide scalable transmission capacity in the optical layer with SCM granularity is now considered by many to be the most promising technology for future transport and distribution of broadband multimedia services.
Recursive, in-place algorithm for the hexagonal orthogonal oriented quadrature image pyramid
Watson, Andrew B.
1989-01-01
Pyramid image transforms have proven useful in image coding and pattern recognition. The hexagonal orthogonal oriented quadrature image pyramid (HOP), transforms an image into a set of orthogonal, oriented, odd and even bandpass subimages. It operates on a hexagonal input lattice and employs seven kernels, each of which occupies a neighborhood consisting of a point and a hexagon of six nearest neighbors. The kernels consist of one lowpass and six bandpass kernels that are orthogonal, self-similar, and localized in space, spatial frequency, orientation, and phase. The kernels are first applied to the image samples to create the first level of the pyramid, then to the lowpass coefficients to create the next level. The resulting pyramid is a compact, efficient image code. Here, a recursive, in-place algorithm for computation of the HOP transform is described. The transform may be regarded as a depth-first traversal of a tree structure. It is shown that the algorithm requires a number of operations that is on the order of the number of pixels.
Niebauer, T M; Constantino, A; Billson, R; Hankla, A; Nelson, P G
2015-06-20
A corner-cube retroreflector has the property that the optical path length for a reflected laser beam is insensitive to rotations about a mathematical point called its optical center (OC). This property is exploited in ballistic absolute gravity meters in which a proof mass containing a corner-cube retroreflector is dropped in a vacuum, and its position is accurately determined with a laser interferometer. In order to avoid vertical position errors when the proof mass rotates during free fall, it is important to collocate its center of mass (COM) with the OC of the retroreflector. This is commonly done using a mechanical scale-based balancing procedure, which has limited accuracy due to the difficulty in finding the exact position of the COM and the OC. This paper describes a novel way to achieve the collocation by incorporating the proof mass into a pendulum and using a quadrature interferometer to interrogate its apparent translation in its twist mode. The mismatch between the COM and OC generates a signal in a quiet part of the spectrum where no mechanical resonance exists. This allows us to tune the position of the COM relative to the OC to an accuracy of about 1 μm in all three axes. This provides a way to directly demonstrate that a rotation of the proof mass by several degrees causes an apparent translation in the direction of the laser beam of less than 1 nm. This technique allows an order of magnitude improvement over traditional methods of balancing.
Xinwei Wang
2016-11-01
Full Text Available Sandwich structures are widely used in practice and thus various engineering theories adopting simplifying assumptions are available. However, most engineering theories of beams, plates and shells cannot recover all stresses accurately through their constitutive equations. Therefore, the soft-core is directly modeled by two-dimensional (2D elasticity theory without any pre-assumption on the displacement field. The top and bottom faces act like the elastic supports on the top and bottom edges of the core. The differential equations of the 2D core are then solved by the harmonic differential quadrature method (HDQM. To circumvent the difficulties in dealing with the locally distributed load by point discrete methods such as the HDQM, a general and rigorous way is proposed to treat the locally distributed load. Detailed formulations are provided. The static behavior of sandwich panels under different locally distributed loads is investigated. For verification, results are compared with data obtained by ABAQUS with very fine meshes. A high degree of accuracy on both displacement and stress has been observed.
Inoshita, Kensuke; Hama, Yoshimitsu; Kishikawa, Hiroki; Goto, Nobuo
2016-12-01
In photonic label routers, various optical signal processing functions are required; these include optical label extraction, recognition of the label, optical switching and buffering controlled by signals based on the label information and network routing tables, and label rewriting. Among these functions, we focus on photonic label recognition. We have proposed two kinds of optical waveguide circuits to recognize 16 quadrature amplitude modulation codes, i.e., recognition from the minimum output port and from the maximum output port. The recognition function was theoretically analyzed and numerically simulated by finite-difference beam-propagation method. We discuss noise tolerance in the circuit and show numerically simulated results to evaluate bit-error-rate (BER) characteristics against optical signal-to-noise ratio (OSNR). The OSNR required to obtain a BER less than 1.0×10-3 for the symbol rate of 2.5 GBaud was 14.5 and 27.0 dB for recognition from the minimum and maximum output, respectively.
Round-robin differential quadrature phase-shift quantum key distribution
Zhou, Chun; Zhang, Ying-Ying; Bao, Wan-Su; Li, Hong-Wei; Wang, Yang; Jiang, Mu-Sheng
2017-02-01
Recently, a round-robin differential phase-shift (RRDPS) protocol was proposed [Nature 509, 475 (2014)], in which the amount of leakage is bounded without monitoring the signal disturbance. Introducing states of the phase-encoded Bennett–Brassard 1984 protocol (PE-BB84) to the RRDPS, this paper presents another quantum key distribution protocol called round-robin differential quadrature phase-shift (RRDQPS) quantum key distribution. Regarding a train of many pulses as a single packet, the sender modulates the phase of each pulse by one of {0, π/2, π, 3π/2}, then the receiver measures each packet with a Mach–Zehnder interferometer having a phase basis of 0 or π/2. The RRDQPS protocol can be implemented with essential similar hardware to the PE-BB84, so it has great compatibility with the current quantum system. Here we analyze the security of the RRDQPS protocol against the intercept-resend attack and the beam-splitting attack. Results show that the proposed protocol inherits the advantages arising from the simplicity of the RRDPS protocol and is more robust against these attacks than the original protocol. Project supported by the National Natural Science Foundation of China (Grant Nos. 61505261 and 11304397) and the National Basic Research Program of China (Grant No. 2013CB338002)
A novel multi-channel quadrature Doppler backward scattering reflectometer on the HL-2A tokamak
Shi, Zhongbing; Zhong, Wulu; Jiang, Min; Yang, Zengchen; Zhang, Boyu; Shi, Peiwan; Chen, Wei; Wen, Jie; Chen, Chengyuan; Fu, Bingzhong; Liu, Zetian; Ding, Xuantong; Yang, Qingwei; Duan, Xuru
2016-11-01
A novel 16-channel fixed frequency Doppler backward scattering (DBS) reflectometer system has been developed on the HL-2A tokamak. This system is based on the filter-based feedback loop microwave source (FFLMS) technique, which has lower phase noise and lower power variation compared with present tunable frequency generation and comb frequency array generation techniques [J. C. Hillesheim et al. Rev. Sci. Instrum. 80, 083507 (2009) and W. A. Peebles et al. Rev. Sci. Instrum. 81, 10D902 (2010)]. The 16-channel DBS system is comprised of four × four-frequency microwave transmitters and direct quadrature demodulation receivers. The working frequencies are 17-24 GHz and 31-38 GHz with the frequency interval of 1 GHz. They are designed to measure the localized intermediate wave-number (k⊥ρ ˜ 1-2, k⊥ ˜ 2-9 cm-1) density fluctuations and the poloidal rotation velocity profile of turbulence. The details of the system design and laboratory tests are presented. Preliminary results of Doppler spectra measured by the multi-channel DBS reflectometer systems are obtained. The plasma rotation and turbulence distribution during supersonic molecular beam injection are analyzed.
Li, L.; Simon, M. K.
2004-02-01
We show that, similar to the trellis-coded modulation representation of MIL-STD shaped offset quadrature phase-shift keying (SOQPSK), offset quadrature phase-shift keying (OQPSK) can be decomposed into a "degraded" trellis encoder and a memoryless mapper. Based on the representations of OQPSK and MIL-STD SOQPSK as trellis-coded modulations, we investigate the potential coding gains achievable from the application of simple outer codes to form a concatenated coding structure with iterative decoding. For MIL-STD SOQPSK, we describe the optimum receiver corresponding to its trellis-coded modulation form and then propose a simplified receiver. The bit-error-rate (BER) performances of both receivers for uncoded and coded MIL-STD SOQPSK are simulated and compared to those of OQPSK and Feher-patented quadrature phase-shift keying (FQPSK). The asymptotic BER performance of MIL-STD SOQPSK also is analyzed and compared to that of OQPSK and FQPSK. Simulation results show that, compared to their uncoded systems, both OQPSK and MIL-STD SOQPSK obtain significant coding gains by applying iterative decoding to either the parallel concatenated coding scheme or the serial one, even when very simple outer codes are used.
Grydeland
2005-01-01
Full Text Available The real and imaginary parts of baseband signals are obtained from a real narrow-band signal by quadrature mixing, i.e. by mixing with cosine and sine signals at the narrow band's selected center frequency. We address the consequences of a delay between the outputs of the quadrature mixer, which arise when digital samples of the quadrature baseband signals are not synchronised, i.e. when the real and imaginary components have been shifted by one or more samples with respect to each other. Through analytical considerations and simulations of such an error on different synthetic signals, we show how this error can be expected to afflict different measurements. In addition, we show the effect of the error on actual incoherent scatter radar data obtained by two different digital receiver systems used in parallel at the EISCAT Svalbard Radar (ESR. The analytical considerations indicate a procedure to correct the error, albeit with some limitations due to a small singular region. We demonstrate the correction procedure on actually afflicted data and compare the results to simultaneously acquired unafflicted data. We also discuss the possible data analysis strategies, including some that avoid dealing directly with the singular region mentioned above.
Barton, Michael
2016-07-21
We introduce Gaussian quadrature rules for spline spaces that are frequently used in Galerkin discretizations to build mass and stiffness matrices. By definition, these spaces are of even degrees. The optimal quadrature rules we recently derived (Bartoň and Calo, 2016) act on spaces of the smallest odd degrees and, therefore, are still slightly sub-optimal. In this work, we derive optimal rules directly for even-degree spaces and therefore further improve our recent result. We use optimal quadrature rules for spaces over two elements as elementary building blocks and use recursively the homotopy continuation concept described in Bartoň and Calo (2016) to derive optimal rules for arbitrary admissible numbers of elements.We demonstrate the proposed methodology on relevant examples, where we derive optimal rules for various even-degree spline spaces. We also discuss convergence of our rules to their asymptotic counterparts, these are the analogues of the midpoint rule of Hughes et al. (2010), that are exact and optimal for infinite domains.
TWO ALGORITHMS FOR LC1 UNCONSTRAINED OPTIMIZATION
Wen-yu Sun; R.J.B.de Sampaio; Jin-Yun Yuan
2000-01-01
In this paper we present two algorithms for LC1 unconstrained optimization problems which use the second order Dini upper directional derivative. These methods are simple and easy to perform. We discuss the related properties of the iteration function, and establish the global and superlinear convergence of our methods.
LC-MS systems for quantitative bioanalysis
Dongen, W.D. van; Niessen, W.M.A.
2012-01-01
LC-MS has become the method-of-choice in small-molecule drug bioanalysis (molecular mass <800 Da) and is also increasingly being applied as an alternative to ligand-binding assays for the bioanalytical determination of biopharmaceuticals. Triple quadrupole MS is the established bioanalytical techniq
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.
Trends in LC-MS and LC-HRMS analysis and characterization of polyphenols in food
Lucci, Paolo; Saurina, Javier; Núñez Burcio, Oscar
2016-01-01
Polyphenols comprise a large family of naturally occurring secondary metabolites of plant-derived foods and are among the principal micronutrients associated with the health beneficial effects of our diet. Liquid chromatography coupled to mass spectrometry (LC-MS) and, in the last few years, high resolution mass spectrometry (LC-HRMS) is playing an important role in the research of polyphenols, not only for the determination of this family of compounds in food matrices, but also for the chara...
A Design of VCO for Controller of Gigabit Ethernet%一种千兆以太网控制器中VCO的设计
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.
Statistical shape and texture model of quadrature phase information for prostate segmentation.
Ghose, Soumya; Oliver, Arnau; Martí, Robert; Lladó, Xavier; Freixenet, Jordi; Mitra, Jhimli; Vilanova, Joan C; Comet-Batlle, Josep; Meriaudeau, Fabrice
2012-01-01
Prostate volume estimation from segmentation of transrectal ultrasound (TRUS) images aids in diagnosis and treatment of prostate hypertrophy and cancer. Computer-aided accurate and computationally efficient prostate segmentation in TRUS images is a challenging task, owing to low signal-to-noise ratio, speckle noise, calcifications, and heterogeneous intensity distribution in the prostate region. A multi-resolution framework using texture features in a parametric deformable statistical model of shape and appearance was developed to segment the prostate. Local phase information of log-Gabor quadrature filter extracted texture of the prostate region in TRUS images. Large bandwidth of log-Gabor filter ensures easy estimation of local orientations, and zero response for a constant signal provides invariance to gray level shift. This aids in enhanced representation of the underlying texture information of the prostate unaffected by speckle noise and imaging artifacts. The parametric model of the propagating contour is derived from principal component analysis of prior shape and texture information of the prostate from the training data. The parameters were modified using prior knowledge of the optimization space to achieve segmentation. The proposed method achieves a mean Dice similarity coefficient value of 0.95 ± 0.02 and mean absolute distance of 1.26 ± 0.51 millimeter when validated with 24 TRUS images of 6 data sets in a leave-one-patient-out validation framework. The proposed method for prostate TRUS image segmentation is computationally efficient and provides accurate prostate segmentations in the presence of intensity heterogeneities and imaging artifacts.
Michael I Koukourakis
Full Text Available LC3s (MAP1-LC3A, B and C are structural proteins of autophagosomal membranes, widely used as biomarkers of autophagy. Whether these three LC3 proteins have a similar biological role in autophagy remains obscure. We examine in parallel the subcellular expression patterns of the three LC3 proteins in a panel of human cancer cell lines, as well as in normal MRC5 fibroblasts and HUVEC, using confocal microscopy and western blot analysis of cell fractions. In the cytoplasm, there was a minimal co-localization between LC3A, B and C staining, suggesting that the relevant autophagosomes are formed by only one out of the three LC3 proteins. LC3A showed a perinuclear and nuclear localization, while LC3B was equally distributed throughout the cytoplasm and localized in the nucleolar regions. LC3C was located in the cytoplasm and strongly in the nuclei (excluding nucleoli, where it extensively co-localized with the LC3A and the Beclin-1 autophagy initiating protein. Beclin 1 is known to contain a nuclear trafficking signal. Blocking nuclear export function by Leptomycin B resulted in nuclear accumulation of all LC3 and Beclin-1 proteins, while Ivermectin that blocks nuclear import showed reduction of accumulation, but not in all cell lines. Since endogenous LC3 proteins are used as major markers of autophagy in clinical studies and cell lines, it is essential to check the specificity of the antibodies used, as the kinetics of these molecules are not identical and may have distinct biological roles. The distinct subcellular expression patterns of LC3s provide a basis for further studies.
LC-MS-based metabolomics: an update.
Fang, Zhong-Ze; Gonzalez, Frank J
2014-08-01
Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics can have a major impact in multiple research fields, especially when combined with other technologies, such as stable isotope tracers and genetically modified mice. This review highlights recent applications of metabolomic technology in the study of xenobiotic metabolism and toxicity, and the understanding of disease pathogenesis and therapeutics. Metabolomics has been employed to study metabolism of noscapine, an aryl hydrocarbon receptor antagonist, and to determine the mechanisms of liver toxicities of rifampicin and isoniazid, trichloroethylene, and gemfibrozil. Metabolomics-based insights into the pathogenesis of inflammatory bowel disease, alcohol-induced liver diseases, non-alcoholic steatohepatitis, and farnesoid X receptor signaling pathway-based therapeutic target discovery will also be discussed. Limitations in metabolomics technology such as sample preparation and lack of LC-MS databases and metabolite standards, need to be resolved in order to improve and broaden the application of metabolomic studies.
Shapiro effect in mesoscopic LC circuit
嵇英华; 罗海梅; 欧阳楚英; 雷敏生
2002-01-01
In this paper we consider the movement of an electron in the single electron tunnel process through a mesoscopiccapacitor. The results show that, due to the Coulomb force, there is a threshold voltage Vt in the mesoscopic LC circuit.When the external voltage is lower than the threshold voltage, the tunnel current value is zero, and the Coulomb blockadephenomenon arises. Furthermore, considering that the mesoscopic dimension is comparable to the coherence length inwhich charge carriers retain the phase remembrance, a weak coupling can be produced through the proximity effectof the normal metal electrons of both electrodes of a mesoscopic capacitor. By varying the external voltage, we canobserve the Shapiro current step on the current-voltage characteristic curve of a mesoscopic LC circuit.
Drosophila roadblock and Chlamydomonas Lc7
Bowman, Aaron B.; Patel-King, Ramila S.; Benashski, Sharon E.; McCaffery, J. Michael; Goldstein, Lawrence S.B.; King, Stephen M.
1999-01-01
Eukaryotic organisms utilize microtubule-dependent motors of the kinesin and dynein superfamilies to generate intracellular movement. To identify new genes involved in the regulation of axonal transport in Drosophila melanogaster, we undertook a screen based upon the sluggish larval phenotype of known motor mutants. One of the mutants identified in this screen, roadblock (robl), exhibits diverse defects in intracellular transport including axonal transport and mitosis. These defects include intra-axonal accumulations of cargoes, severe axonal degeneration, and aberrant chromosome segregation. The gene identified by robl encodes a 97–amino acid polypeptide that is 57% identical (70% similar) to the 105–amino acid Chlamydomonas outer arm dynein–associated protein LC7, also reported here. Both robl and LC7 have homology to several other genes from fruit fly, nematode, and mammals, but not Saccharomyces cerevisiae. Furthermore, we demonstrate that members of this family of proteins are associated with both flagellar outer arm dynein and Drosophila and rat brain cytoplasmic dynein. We propose that roadblock/LC7 family members may modulate specific dynein functions. PMID:10402468
Serés Roig, Eulalia; Magill, Arthur W; Donati, Guillaume; Meyerspeer, Martin; Xin, Lijing; Ipek, Ozlem; Gruetter, Rolf
2015-02-01
Carbon-13 magnetic resonance spectroscopy ((13) C-MRS) is challenging because of the inherent low sensitivity of (13) C detection and the need for radiofrequency transmission at the (1) H frequency while receiving the (13) C signal, the latter requiring electrical decoupling of the (13) C and (1) H radiofrequency channels. In this study, we added traps to the (13) C coil to construct a quadrature-(13) C/quadrature-(1) H surface coil, with sufficient isolation between channels to allow simultaneous operation at both frequencies without compromise in coil performance. Isolation between channels was evaluated on the bench by measuring all coupling parameters. The quadrature mode of the quadrature-(13) C coil was assessed using in vitro (23) Na gradient echo images. The signal-to-noise ratio (SNR) was measured on the glycogen and glucose resonances by (13) C-MRS in vitro, compared with that obtained with a linear-(13) C/quadrature-(1) H coil, and validated by (13) C-MRS in vivo in the human calf at 7T. Isolation between channels was better than -30 dB. The (23) Na gradient echo images indicate a region where the field is strongly circularly polarized. The quadrature coil provided an SNR enhancement over a linear coil of 1.4, in vitro and in vivo. It is feasible to construct a double-quadrature (13) C-(1) H surface coil for proton decoupled sensitivity enhanced (13) C-NMR spectroscopy in humans at 7T. © 2014 Wiley Periodicals, Inc.
Levesque, Philippe; Sawan, Mohamad
2009-08-01
A fully hardware-based real-time digital wideband quadrature demodulation processor based on the Hilbert transform is proposed to process ultrasound radio frequency signals. The presented architecture combines 2 finite impulse response (FIR) filters to process in-phase and quadrature signals and includes a piecewise linear approximation architecture that performs the required square root operations. The proposed implementation enables flexibility to support different transducers with its ability to load on-the-fly different FIR filter coefficient sets. The complexity and accuracy of the demodulator processor are analyzed with simulated RF data; a normalized residual sum-of-squares cost function is used for comparison with the Matlab Hilbert function. Three implementations are integrated into a hand-held ultrasound system for experimental accuracy and performance evaluation. Real-time images were acquired from a reference phantom, demonstrating the feasibility of using the presented architecture to perform real-time digital quadrature demodulation of ultrasonic signal echoes. Experimental results show that the implementation, using only 2942 slices and 3 dedicated digital multipliers of a low-cost and low-power field-programmable gate array (FPGA) is accurate relative to a comparable software- based system; axial and lateral resolution of 1 mm and 2 mm, respectively, were obtained with a 12-mm piezoelectric transducer without postprocessing. Because the processing and sampling rates are the same, high-frequency ultrasound signals can be processed as well. For a 15-frame-per-second display, the hand-held ultrasonic imaging-processing core (FPGA, memory) requires only 45 mW (dynamic) when using a 5-MHz single-element piezoelectric transducer.
Woods, M. P. [University College of London, Department of Physics and Astronomy, London WC1E 6BT (United Kingdom); Centre for Quantum Technologies, National University of Singapore (Singapore); QuTech, Delft University of Technology, Lorentzweg 1, 2611 CJ Delft (Netherlands); Plenio, M. B. [Institute für Theoretische Physik, Universität Ulm, D-89069 Ulm (Germany)
2016-02-15
Instances of discrete quantum systems coupled to a continuum of oscillators are ubiquitous in physics. Often the continua are approximated by a discrete set of modes. We derive error bounds on expectation values of system observables that have been time evolved under such discretised Hamiltonians. These bounds take on the form of a function of time and the number of discrete modes, where the discrete modes are chosen according to Gauss quadrature rules. The derivation makes use of tools from the field of Lieb-Robinson bounds and the theory of orthonormal polynomials.
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%.
Large eddy simulations of coal jet flame ignition using the direct quadrature method of moments
Pedel, Julien
The Direct Quadrature Method of Moments (DQMOM) was implemented in the Large Eddy Simulation (LES) tool ARCHES to model coal particles. LES coupled with DQMOM was first applied to nonreacting particle-laden turbulent jets. Simulation results were compared to experimental data and accurately modeled a wide range of particle behaviors, such as particle jet waviness, spreading, break up, particle clustering and segregation, in different configurations. Simulations also accurately predicted the mean axial velocity along the centerline for both the gas phase and the solid phase, thus demonstrating the validity of the approach to model particles in turbulent flows. LES was then applied to the prediction of pulverized coal flame ignition. The stability of an oxy-coal flame as a function of changing primary gas composition (CO2 and O2) was first investigated. Flame stability was measured using optical measurements of the flame standoff distance in a 40 kW pilot facility. Large Eddy Simulations (LES) of the facility provided valuable insight into the experimentally observed data and the importance of factors such as heterogeneous reactions, radiation or wall temperature. The effects of three parameters on the flame stand-off distance were studied and simulation predictions were compared to experimental data using the data collaboration method. An additional validation study of the ARCHES LES tool was then performed on an air-fired pulverized coal jet flame ignited by a preheated gas flow. The simulation results were compared qualitatively and quantitatively to experimental observations for different inlet stoichiometric ratios. LES simulations were able to capture the various combustion regimes observed during flame ignition and to accurately model the flame stand-off distance sensitivity to the stoichiometric ratio. Gas temperature and coal burnout predictions were also examined and showed good agreement with experimental data. Overall, this research shows that high
Accurate LC peak boundary detection for ¹⁶O/¹⁸O labeled LC-MS data.
Jian Cui
Full Text Available In liquid chromatography-mass spectrometry (LC-MS, parts of LC peaks are often corrupted by their co-eluting peptides, which results in increased quantification variance. In this paper, we propose to apply accurate LC peak boundary detection to remove the corrupted part of LC peaks. Accurate LC peak boundary detection is achieved by checking the consistency of intensity patterns within peptide elution time ranges. In addition, we remove peptides with erroneous mass assignment through model fitness check, which compares observed intensity patterns to theoretically constructed ones. The proposed algorithm can significantly improve the accuracy and precision of peptide ratio measurements.
Xu, Cheng; Gao, Guanjun; Chen, Sai; Zhang, Jie
2016-12-01
In this paper we investigate Faster-than-Nyquist Discrete-Fourier-Transform spread Orthogonal Frequency Division Multiplexing (FTN-DFTs-OFDM) signaling which combines the features of both single carrier FTN and OFDM system. By introducing the quadrature duo-binary (QDB) filtering at the receiver side, the transmitted OFDM signal can be packed in a sub-Nyquist spacing, which improves the spectral efficiency (SE) compared to conventional detection schemes. Maximum a posteriori (MAP) and maximum likelihood sequence estimation (MLSE) criteria have been both used and compared to find an optimal equalization scheme for combating FTN multiplexing at transmitter side and QDB filtering at receiver side. The simulations result show that by applying QDB filtering at the receiver side, the back-to-back (BTB) required optical signal noise ratio (OSNR) at bit error rate (BER) of 1 × 10-2 is reduced by 1.5-dB for 20-GHz spaced 128-Gb/s polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) signal, achieving a SE of 6.4-b/s/Hz.
UAV Digital Tracking Array Design, Development and Testing
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
Ye Li
Full Text Available The use of quadrature RF magnetic fields has been demonstrated to be an efficient method to reduce transmit power and to increase the signal-to-noise (SNR in magnetic resonance (MR imaging. The goal of this project was to develop a new method using the common-mode and differential-mode (CMDM technique for compact, planar, distributed-element quadrature transmit/receive resonators for MR signal excitation and detection and to investigate its performance for MR imaging, particularly, at ultrahigh magnetic fields. A prototype resonator based on CMDM method implemented by using microstrip transmission line was designed and fabricated for 7T imaging. Both the common mode (CM and the differential mode (DM of the resonator were tuned and matched at 298MHz independently. Numerical electromagnetic simulation was performed to verify the orthogonal B1 field direction of the two modes of the CMDM resonator. Both workbench tests and MR imaging experiments were carried out to evaluate the performance. The intrinsic decoupling between the two modes of the CMDM resonator was demonstrated by the bench test, showing a better than -36 dB transmission coefficient between the two modes at resonance frequency. The MR images acquired by using each mode and the images combined in quadrature showed that the CM and DM of the proposed resonator provided similar B1 coverage and achieved SNR improvement in the entire region of interest. The simulation and experimental results demonstrate that the proposed CMDM method with distributed-element transmission line technique is a feasible and efficient technique for planar quadrature RF coil design at ultrahigh fields, providing intrinsic decoupling between two quadrature channels and high frequency capability. Due to its simple and compact geometry and easy implementation of decoupling methods, the CMDM quadrature resonator can possibly be a good candidate for design blocks in multichannel RF coil arrays.
Li, Ye; Yu, Baiying; Pang, Yong; Vigneron, Daniel B; Zhang, Xiaoliang
2013-01-01
The use of quadrature RF magnetic fields has been demonstrated to be an efficient method to reduce transmit power and to increase the signal-to-noise (SNR) in magnetic resonance (MR) imaging. The goal of this project was to develop a new method using the common-mode and differential-mode (CMDM) technique for compact, planar, distributed-element quadrature transmit/receive resonators for MR signal excitation and detection and to investigate its performance for MR imaging, particularly, at ultrahigh magnetic fields. A prototype resonator based on CMDM method implemented by using microstrip transmission line was designed and fabricated for 7T imaging. Both the common mode (CM) and the differential mode (DM) of the resonator were tuned and matched at 298MHz independently. Numerical electromagnetic simulation was performed to verify the orthogonal B1 field direction of the two modes of the CMDM resonator. Both workbench tests and MR imaging experiments were carried out to evaluate the performance. The intrinsic decoupling between the two modes of the CMDM resonator was demonstrated by the bench test, showing a better than -36 dB transmission coefficient between the two modes at resonance frequency. The MR images acquired by using each mode and the images combined in quadrature showed that the CM and DM of the proposed resonator provided similar B1 coverage and achieved SNR improvement in the entire region of interest. The simulation and experimental results demonstrate that the proposed CMDM method with distributed-element transmission line technique is a feasible and efficient technique for planar quadrature RF coil design at ultrahigh fields, providing intrinsic decoupling between two quadrature channels and high frequency capability. Due to its simple and compact geometry and easy implementation of decoupling methods, the CMDM quadrature resonator can possibly be a good candidate for design blocks in multichannel RF coil arrays.
2008-01-01
We designed the experimental generation system of the optical GHZ-like and cluster-like quadripartite entangled states for continuous variables.We theoretically demonstrated that the two different types of quadripartite entangled states can be obtained by the linearly optical transformation of four amplitude-quadrature and phase-quadrature squeezed states produced from a pair of nondegenerate optical parametric amplifiers under appropriate phase relations.The criteria for full inseparability of quadripartite cluster-like state were deduced,and the dependency of the quadripartite entanglement on the initial squeezing degree,the transmission efficiencies of the system and the detection efficiency of homodyne detection were numerically calculated.
Preprocessing and Analysis of LC-MS-Based Proteomic Data.
Tsai, Tsung-Heng; Wang, Minkun; Ressom, Habtom W
2016-01-01
Liquid chromatography coupled with mass spectrometry (LC-MS) has been widely used for profiling protein expression levels. This chapter is focused on LC-MS data preprocessing, which is a crucial step in the analysis of LC-MS based proteomics. We provide a high-level overview, highlight associated challenges, and present a step-by-step example for analysis of data from LC-MS based untargeted proteomic study. Furthermore, key procedures and relevant issues with the subsequent analysis by multiple reaction monitoring (MRM) are discussed.
Suess, Steven; Corti, G.; Poletto, G.; Sterling, A.; Moore, R.
2006-01-01
At the time of the spring 2003 Ulysses-SOHO-Sun quadrature, Ulysses was off the East limb of the Sun at 14.5 degrees north latitude and 4.91 AU. LASCO/C2 images show small transient events that originated from near the limb on May 25, 26 and 27 in the north-east quadrant, along with a large Coronal Mass Ejection (CME) that originated from an active region near disk center on May 26. Ulysses data bear clear signatures of the large CME, specifically including an enhanced abundance of highly ionized Fe. SOHO/UVCS spectra at 1.75 solar radii, near the radial direction to Ulysses, give no evidence of emission from high temperature lines, even for the large CME: instead, for the small events, occasional transient high emission in cool lines was observed, such as the CIII 977 Angstrom line usually absent at coronal levels. Each of these events lasted ca. 1 hour or less and never affected lines from ions forming above ca. 106K. Compact eruptions in Helium 304 Angstrom EIT images, related to the small UVCS transients, were observed at the limb of the Sun over the same period. At least one of these surge events produced a narrow CME observed in LASCO/C2. Most probably all these events are compact magnetic explosions (surges/jets, from around a small island of included polarity) which ejected cool material from lower levels. Ulysses data have been analyzed to find evidence of the cool, narrow CME events, but none or little was found. This puzzling scenario, where events seen by UVCS have no in situ counterparts and vice versa, can be partially explained once the region where the large CME originated is recognized as being at the center of the solar disk so that the CME material was actually much further from the Sun than the 1.7 Rsun height of the UVCS slit off the limb. Conversely, the narrow events may simply have missed Ulysses or been too brief for reliable signatures in composition and ionization state. A basic feature demonstrated by these observations is that large
Fractional RC and LC Electrical Circuits
Gómez-Aguilar José Francisco
2014-04-01
Full Text Available In this paper we propose a fractional differential equation for the electrical RC and LC circuit in terms of the fractional time derivatives of the Caputo type. The order of the derivative being considered is 0 < ɣ ≤1. To keep the dimensionality of the physical parameters R, L, C the new parameter σ is introduced. This parameter characterizes the existence of fractional structures in the system. A relation between the fractional order time derivative ɣ and the new parameter σ is found. The numeric Laplace transform method was used for the simulation of the equations results. The results show that the fractional differential equations generalize the behavior of the charge, voltage and current depending of the values of ɣ. The classical cases are recovered by taking the limit when ɣ = 1. An analysis in the frequency domain of an RC circuit shows the application and use of fractional order differential equations.
Compact electric-LC resonators for metamaterials
Withayachumnankul, Withawat; Abbott, Derek
2010-01-01
Alternative designs to an electric-LC (ELC) resonator, which is a type of metamaterial inclusion, are presented in this article. Fitting the resonator with an interdigital capacitor (IDC) helps to increase the total capacitance of the structure. In effect, its resonance frequency is shifted downwards. This implies a decreased overall resonator size with respect to its operating wavelength. As a result, the metamaterial, composed of an array of IDC-loaded ELC resonators with their collective electromagnetic response, possesses improved homogeneity and hence is less influenced by diffraction effects of individual cells. The impact of incorporating an IDC into ELC resonators in terms of the electrical size at resonance and other relevant properties are investigated through both simulation and experiment.
Identification of forced degradation products of itopride by LC-PDA and LC-MS
Payal Joshi
2011-01-01
Full Text Available Degradation products of itopride formed under different forced conditions have been identified using LC-PDA and LC-MS techniques. Itopride was subjected to forced degradation under the conditions of hydrolysis, photolysis, oxidation, dry and wet heat, in accordance with the International Conference on Harmonization. The stress solutions were chromatographed on reversed phase C18 (250×4.6 mm, 5 μm column with a mobile phase methanol:water (55:45, v/v at a detection wavelength of 215 nm. Itopride degraded in acid, alkali and oxidative stress conditions. The stability indicating method was developed and validated. The degradation pathway of the drug to products II-VIII is proposed.
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
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.
Seong, Tae-Je
The similarity of item and ability parameter estimations was investigated using two numerical analysis techniques via marginal maximum likelihood estimation (MMLE) with a large simulated data set (n=1,000 examinees) and changing the number of quadrature points. MMLE estimation uses a numerical analysis technique to integrate examinees' abilities…
de Basabe, Jonás D.
2011-08-01
Zhou & Greenhalgh have recently presented an application of the Gaussian quadrature grid to seismic modelling in which the authors propose a meshing scheme that partitions the domain independently of the discontinuities in the media parameters. This comment aims to clarify the implications that this strategy has on the accuracy.
Sato, Takanori; Kanno, Kazutaka; Bunsen, Masatoshi
2016-09-01
We applied complex linear minimum mean-squared-error equalization to spatially quadrature-amplitude-modulated signals in holographic data storage (HDS). The equalization technique can improve dispersion in constellation outputs due to intersymbol interference. We confirm the effectiveness of the equalization technique in numerical simulations and basic optical experiments. Our numerical results have shown that intersymbol interference of a retrieved signal in a HDS system can be improved by using the equalization technique. In our experiments, a mean squared error (MSE), which indicates the deviation from an ideal signal, has been used for quantitatively evaluating the dispersion of equalized signals. Our equalization technique has been able to improve the MSE. However, symbols in the equalized signal have remained inseparable. To further improve the MSE and make the symbols separable, reducing errors in repeated measurements is our future task.
Smith, A. C.; Yang, H.
1989-01-01
The quadrature phase detection technique was used to simultaneously monitor the phase and amplitude of a toneburst signal normally reflected from an adhesively bonded steel-to-rubber interface. The measured phase was found to show a positive shift for all bonded samples with respect to the disbonded state - the phase shift being larger for samples with weaker bonds, as manifested by smaller values of applied tensile loads at failure. A model calculation, which incorporates the concept of interfacial strength into the usual problem of wave propagation in multilayered media, was used to deduce a bond-quality parameter from an experimentally measured phase shift. This bond-quality parameter was found to be correlated with the tensile strength of the adhesive bonds at failure loads.
Sainath, Kamalesh
2014-01-01
We discuss the application of Complex-Plane Gauss-Laguerre Quadrature (CGLQ) to efficiently evaluate two-dimensional Fourier integrals arising as the solution to electromagnetic fields radiated by elementary dipole antennas embedded within planar-layered media with arbitrary material parameters. More specifically, we apply CGLQ to the long-standing problem of rapidly and efficiently evaluating the semi-infinite length "tails" of the Fourier integral path while simultaneously and robustly guaranteeing absolute, exponential convergence of the field solution despite diversity in the doubly anisotropic layer parameters, source type (i.e., electric or equivalent magnetic dipole), source orientation, observed field type (magnetic or electric), (non-zero) frequency, and (non-zero) source-observer separation geometry. The proposed algorithm exhibits robustness despite unique challenges arising for the fast evaluation of such two-dimensional integrals. Herein, we (1) develop the mathematical treatment to rigorously ev...
Kim, Jong-Ahn; Kang, Chu-Shik; Eom, Tae Bong; Jin, Jonghan; Suh, Ho Suhng; Kim, Jae Wan
2014-07-10
A thickness measurement system is proposed for in-line inspection of thickness variation of flat glass panels. Multi-reflection on the surfaces of glass panel generates an interference signal whose phase is proportional to the thickness of the glass panel. For accurate and stable calculation of the phase value, we obtain quadrature interference signals using a current modulation technique. The proposed system can measure a thickness profile with high speed and nanometric resolution, and obtain higher accuracy through real-time nonlinear error compensation. The thickness profile, measured by a transmissive-type experimental setup, coincided with a comparative result obtained using a contact-type thickness measurement system within the range of ±40 nm. The standard deviations of the measured thickness profiles and their waviness components were less than 3 nm with a scanning speed of 300 mm/s.
Quadrature Rotating-Frame Gradient Fields for Ultra-Low FieldNuclear Magnetic Resonance and Imaging
Bouchard, Louis-Serge
2005-12-30
Magnetic resonance imaging (MRI) in very low fields isfundamentally limited by untruncated concomitant gradients which causesevere distortions in image acquisition and volume selection if thegradient fields are strong compared to the static field. In this paper,it is shown that gradient fields oscillating in quadrature can be usedfor spatial encoding in low fields and provide substantial improvementsover conventional encoding methods using static gradients. In particular,cases where the gradient field is comparable to or higher than theexternal field, Gmax/B0>1, are examined. It is shown thatundistorted slice selection and image encoding is possible because ofsmaller geometric phase errors introduced during cyclic motions of theHamiltonian. In the low field limit (Gmax/B_0 ->infinity) sliceselection is achieved with a combination of soft pulse segments and acoherent train of hard pulses to average out concomitant fields over thefast scale of the rf Hamiltonian.
Cui, Yue; Zhang, Min; Zhan, Yueying; Wang, Danshi; Huang, Shanguo
2016-08-01
A scheme for optical parallel encryption/decryption of quadrature phase shift keying (QPSK) signals is proposed, in which three QPSK signals at 10 Gb/s are encrypted and decrypted simultaneously in the optical domain through nondegenerate four-wave mixing in a highly nonlinear fiber. The results of theoretical analysis and simulations show that the scheme can perform high-speed wiretapping against the encryption of parallel signals and receiver sensitivities of encrypted signal and the decrypted signal are -25.9 and -23.8 dBm, respectively, at the forward error correction threshold. The results are useful for designing high-speed encryption/decryption of advanced modulated signals and thus enhancing the physical layer security of optical networks.
Sun, Dan; Garmory, Andrew; Page, Gary J.
2017-02-01
For flows where the particle number density is low and the Stokes number is relatively high, as found when sand or ice is ingested into aircraft gas turbine engines, streams of particles can cross each other's path or bounce from a solid surface without being influenced by inter-particle collisions. The aim of this work is to develop an Eulerian method to simulate these types of flow. To this end, a two-node quadrature-based moment method using 13 moments is proposed. In the proposed algorithm thirteen moments of particle velocity, including cross-moments of second order, are used to determine the weights and abscissas of the two nodes and to set up the association between the velocity components in each node. Previous Quadrature Method of Moments (QMOM) algorithms either use more than two nodes, leading to increased computational expense, or are shown here to give incorrect results under some circumstances. This method gives the computational efficiency advantages of only needing two particle phase velocity fields whilst ensuring that a correct combination of weights and abscissas is returned for any arbitrary combination of particle trajectories without the need for any further assumptions. Particle crossing and wall bouncing with arbitrary combinations of angles are demonstrated using the method in a two-dimensional scheme. The ability of the scheme to include the presence of drag from a carrier phase is also demonstrated, as is bouncing off surfaces with inelastic collisions. The method is also applied to the Taylor-Green vortex flow test case and is found to give results superior to the existing two-node QMOM method and is in good agreement with results from Lagrangian modelling of this case.
On-line coupled LC-LC-GC for irradiation detection in complex lipid matrices
Schulzki, G. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Spiegelberg, A. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Helle, N. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Boegl, K.W. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Schreiber, G.A. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany))
1993-01-01
Since sample preparation with HPLC coupled on-line to the GC has been performed for only a few weeks in our laboratory, the results presented give a first look at what can be done by means of this technique. Even difficult samples as the described fish species, where an unequivocal identification regarding an irradiation treatment seemed to become a hopeless enterprise, could be managed. Because of the greater variety of fatty acids in fish ''new'' radiation-induced hydrocarbons were available. According to the theory of Nawar in addition to 16:2 and 17:2 hydrocarbons we have looked for in irradiated meat, further alkadienes appeared in irradiated fish, which were 14:2, 18:2 and 20:2. Analysis of the alkadiene-fraction, transferred to the GC after a two step LC clean up, resulted in an unequivocal identification of all fish samples as well as the fruits and sponge cake. For fruits and sponge cake the detection limit seems to be clearly below 0.5 kGy. It can further be lowered by increasing the amount of lipid whereas the upper limit for a certain LC column has to be determined. In contrast to these samples only qualitative results were obtained for fish. In the case of sponge cake for the first time irradiation of a component of a heat treated food was detected. Further investigations regarding reproducibility, dose dependence and detection limit have to be done. On-line coupled (LC-)LC-GC was proved to be a highly efficient method for analysis of complex samples. In contrast to off-line Florisil column chromatography only a small part of the initial lipid material is needed because the complete hydrocarbon fraction is transferred on-line to the GC. This offers the possibility to analyze even foods with a low fat content like various seafoods. Classification of the hydrocarbon fraction by a two step LC may facilitate the identification of the radiolytic products also if no mass spectrometric detection system is available. (orig./vhe)
Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS.
Tatsis, E.C.; Boeren, J.A.; Exarchou, V.; Troganis, A.N.; Vervoort, J.J.M.; Gerothanassis, I.P.
2007-01-01
The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Ac
Matrix effects break the LC behavior rule for analytes in LC-MS/MS analysis of biological samples
High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are generally accepted as the preferred techniques for detecting and quantitating analytes of interest in biological matrices on the basis of the rule that one chemical compound yields one LC-...
LC, MSn and LC-MS/MS studies for the characterization of degradation products of amlodipine
Ravi N. Tiwari; Nishit Shah; Vikas Bhalani; Anand Mahajan
2015-01-01
In the present study, comprehensive stress testing of amlodipine (AM) was carried out according to International Conference on Harmonization (ICH) Q1A(R2) guideline. AM was subjected to acidic, neutral and alkaline hydrolysis, oxidation, photolysis and thermal stress conditions. The drug showed instability in acidic and alkaline conditions, while it remained stable to neutral, oxidative, light and thermal stress. A total of nine degradation products (DPs) were formed from AM, which could be separated by the developed gradient LC method on a C18 column. The products formed under various stress conditions were investigated by LC–MS/MS analysis. The previously developed LC method was suitably modified for LC–MS/MS studies by replacing phosphate buffer with ammonium acetate buffer of the same concentration (pH 5.0). A complete fragmentation pathway of the drug was first established to characterize all the degradation products using LC–MS/MS and multi-stage mass (MSn) fragmentation studies. The obtained mass values were used to study elemental compositions, and the total information helped with the identification of DPs, along with its degradation pathway.
Study on Low Phase Noise Multi-Band VCO Wideband Phase Locked Loop%低相噪超多频段VCO宽带锁相环的研究
薛鹏; 郑欢; 孙恒青; 向冰
2016-01-01
为了解决宽带锁相环设计中相位噪声和输出频率范围的矛盾,分析并设计了一种基于超多频段压控振荡器(VCO)锁相环的方案.该方案通过降低VCO的频率灵敏度和每个VCO配置LC矩阵等效多个VCO的方法,使VCO在保证输出的频率范围的同时,优化了相位噪声.实验结果发现,该方案可以使锁相环在保证较大的输出频率范围前提下拥有更低的相位噪声.
袁寿财; 郑月明
2005-01-01
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 0.6 μm CMOS technology and its SPICE model. SPICE simulation results show that at 2.5V supply voltage, the designed PLL can operate over 1000 MHz and dissipate power less than 50mW.%锁相环(PLL)是VLSI系统的重要单元电路之一,为了实现高速低功耗的CMOS锁相环,用传输门VCO和动态反相器PFD电路设计CMOS锁相环.传输门结构VCO具有高速、低电压和低功耗的特性,而动态反相器PFD具有功耗低和面积小的特点.SPICE模拟表明,当电源电压为2.5 V时,基于0.6 μm CMOS工艺设计的CMOS锁相环电路,工作频率高达1000 MHz,而功耗低于50mW.
Screening antioxidants using LC-MS: case study with cocoa.
Calderón, Angela I; Wright, Brian J; Hurst, W Jeffrey; van Breemen, Richard B
2009-07-08
Oxidative stress enhances pathological processes contributing to cancer, cardiovascular disease, and neurodegenerative diseases, and dietary antioxidants may counteract these deleterious processes. Because rapid methods to evaluate and compare food products for antioxidant benefits are needed, a new assay based on liquid chromatography-mass spectrometry (LC-MS) was developed for the identification and quantitative analysis of antioxidants in complex natural product samples such as food extracts. This assay is based on the comparison of electrospray LC-MS profiles of sample extracts before and after treatment with reactive oxygen species such as hydrogen peroxide or 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). Using this assay, methanolic extracts of cocoa powder were analyzed, and procyanidins were found to be the most potent antioxidant species. These species were identified using LC-MS, LC-MS/MS, accurate mass measurement, and comparison with reference standards. Furthermore, LC-MS was used to determine the levels of these species in cocoa samples. Catechin and epicatechin were the most abundant antioxidants followed by their dimers and trimers. The most potent antioxidants in cocoa were trimers and dimers of catechin and epicatechin, such as procyanidin B2, followed by catechin and epicatechin. This new LC-MS assay facilitates the rapid identification and then the determination of the relative antioxidant activities of individual antioxidant species in complex natural product samples and food products such as cocoa.
高文华
2015-01-01
The total differential quadrature of function of two variables problem was discussed.Analyzed the selection of the path of integration for total differential quadrature of function of two variables through examples.Then total differential quadrature of function of two variables in complex connected domain was explored,the condition for total differential quadrature of function of two variables was generalized.%探讨了高等数学中二元函数全微分的求积问题。按照循序渐进的方式，举例分析二元函数全微分求积时积分路径的选取问题，探究复连通区域内二元函数全微分求积问题，推广了二元函数全微分求积题目的条件。
Domínguez-Serna, Francisco A.; Mendieta-Jimenez, Francisco J.; Rojas, Fernando
2017-10-01
We study quantum correlations and discord in a bipartite continuous variable hybrid system formed by linear combinations of coherent states \\mathinner {|{α }\\rangle } and single photon-added coherent states of the form \\mathinner {|{ψ }\\rangle }_{ {dp(pa)}}= \\mathcal {N}/√{2} (\\hat{a}^\\dagger \\mathinner {|{α }\\rangle }_a\\mathinner {|{α }\\rangle }_b ± \\hat{b}^\\dagger \\mathinner {|{α }\\rangle }_a\\mathinner {|{α }\\rangle }_b). We stablish a relationship between the quantum discord with a local observable (the quadrature variance for one subsystem) under the influence of scattering and phase fluctuation noise. For the pure states the quantum correlations are characterized by means of measurement induced disturbance (MID) with simultaneous quadrature measurements. In a scenario where homodyne conditional measurements are available we show that the MID provides an easy way to select optimal phases to obtain information of the maximal correlations in the channels. The quantum correlations of these entangled states with channel losses are quantitatively characterized with the quantum discord (QD) with a displaced qubit projector. We observe that as scattering increases, QD decreases monotonically. At the same time for the state \\mathinner {|{ψ }\\rangle }_{ {dp}}, QD is more resistant to high phase fluctuations when the average photon number n_0 is bigger than zero, but if phase fluctuations are low, QD is more resistant if n_0=0. For the dp model with scattering, we obtain an analytical expression of the QD as a function of the observable quadrature variance in a local subsystem. This relation allows us to have a way to obtain the degree of QD in the channel by just measuring a local property observable such as the quadrature variance. For the other model this relation still exists but is explored numerically. This relation is an important result that allows to identify quantum processing capabilities in terms of just local observables.
AL-SAIF A.S.J.; ZHU Zheng-you
2005-01-01
The problem of two-dimensional steady flow of an incompressible second-order viscoelastic fluid coupled with heat transfer between parallel plates was considered.A viscous dissipation function was included in the energy equation.When the elastic property of the fluid is weaker, the zeroth-order and first-order approximate governing equations were obtained by means of the perturbation method.To understand the behavior of flow near the tube wall, the half-domain was divided into two sub-domains, in which one is a thin layer near the wall called the inner domain and the remainder is called the outer domain.The governing equations in the inner domain and in the outer domain were discretized respectively by using the Differential Quadrature Method (DQM).The matching conditions at the interface between the inner and outer domains were presented.An iterative method for solving these discretized equations was given in this paper.The numerical results obtained agree with existing results.
0.8-5.2GHz Broad-Band SiGe-MMIC Quadrature Mixer for Software Defined Radio Receiver
Murakami, Keishi; Suematsu, Noriharu; Tsutsumi, Koji; Kanazawa, Gakushi; Sekine, Tomotsugu; Kubo, Hiroshi; Isota, Yoji
For the next generation wireless terminals used in the software defined radio (SDR), multi-band / multi-mode transceivers and their MMIC are required which cover the wide RF frequency range from several hundreds MHz up to several GHz. In this paper, 0.8-5.2GHz broad-band SiGe-MMIC quadrature mixer (Q-MIX) for multi-band / multi-mode direct conversion receiver has been developed. By using a static type frequency divider as a 90 degrees local (LO) power divider, measured error vector magnitude (EVM) of less than 3.1% can be achieved in the cases of 0.8/2.1GHz W-CDMA and 5.2GHz wireless Local Area Network (LAN) (IEEE 802.11a) reception. This Q-MIX also shows broad-band characteristic for base-band signal and is applicable for 4G cellular. By using fabricated Q-MIX, a multi-band / multi-mode (1.9GHz (3rd generation cellular (W-CDMA)) / 5.2GHz (4th generation cellular (Multi-Carrier (MC)-CDMA))) receiver has been developed and it has firstly demonstrated the successful reception of motion picture via W-CDMA and MC-CDMA.
Malekzadeh, P.; Setoodeh, A. R.; Barmshouri, E.
2008-08-01
An accurate and efficient solution procedure based on the two-dimensional elasticity theory for free vibration of arbitrary laminated thick circular deep arches with some combinations of classical boundary conditions is introduced. In order to accurately represent the variation of strain across the thickness, the layerwise theory is used to approximate the displacement components in the radial direction. Employing Hamilton's principle, the discretized form of the equations of motion and the related boundary conditions in the radial direction are obtained. The resulting governing equations are then discretized using the differential quadrature method (DQM). After performing the convergence studies, new results for laminated arches with different set of boundary conditions are developed. Additionally, different values of the arch parameters such as opening angle, thickness-to-length and orthotropy ratios are considered. In all cases, comparisons with the results obtained using the finite element software 'ABAQUS' and also with those of the first- and higher-order shear deformation theories available in the literature are performed. Close agreements, especially with those of ABAQUS, are achieved.
LI Yu-hong; ZHOU Zheng
2005-01-01
A rate adaptive multi-band ultra-wideband (UWB) system based on the quadrature fractal modulation (QFM)scheme was proposed. Exploring the use of homogeneous signals as modulating waveforms in UWB system, the signal within each 528MHz sub-band was divided into 8 different frequency bandwidths using wavelets transform and these data sequences to be transmitted were embedded into homogeneous waveforms. It is found that the use of homogeneous signals in such UWB system is quite feasible, leadings to a novel multi-rate diversity strategy. Within each 528MHz sub-band, the UWB-QFM system can provide much higher data rates than that of the UWB orthogonal frequency division multiplexing (OFDM) system. Simulation results also show that the bit error rate (BER) performance of the UWB-QFM system achieves a greatly improvement over existing UWB-OFDM system. Due to the fractal properties of the homogeneous signals, these data sequences to be transmitted can be recovered using arbitrarily short receiver signal.
Sainath, Kamalesh; Teixeira, Fernando L
2014-05-01
We discuss the application of complex-plane Gauss-Laguerre quadrature (CGLQ) to efficiently evaluate two-dimensional Fourier integrals arising as the solution to electromagnetic fields radiated by elementary dipole antennas embedded within planar-layered media exhibiting arbitrary material parameters. More specifically, we apply CGLQ to the long-standing problem of rapidly and efficiently evaluating the semi-infinite length "tails" of the Fourier integral path while simultaneously and robustly guaranteeing absolute, exponential convergence of the field solution despite diversity in the doubly anisotropic layer parameters, source type (i.e., electric or equivalent magnetic dipole), source orientation, observed field type (magnetic or electric), (nonzero) frequency, and (nonzero) source-observer separation geometry. The proposed algorithm exhibits robustness despite unique challenges arising for the fast evaluation of such two-dimensional integrals. Herein we develop the mathematical treatment to rigorously evaluate the tail integrals using CGLQ, as well as discuss and address the specific issues posed to the CGLQ method when anisotropic, layered media are present. To empirically demonstrate the CGLQ algorithm's computational efficiency, versatility, and accuracy, we perform a convergence analysis along with two case studies related to modeling of electromagnetic resistivity tools employed in geophysical prospection of layered, anisotropic Earth media and validating the ability of isoimpedance substrates to enhance the radiation performance of planar antennas placed in close proximity to metallic ground planes.
Hort, R. D.; Revil, A.; Munakata-Marr, J.; Mao, D.
2015-07-01
Electrical resistivity measurements can potentially be used to remotely monitor fate and transport of ionic oxidants such as permanganate (MnO4-) during in situ chemical oxidation (ISCO) of contaminants like trichloroethene (TCE). Time-lapse two-dimensional bulk conductivity and induced polarization surveys conducted during a sand tank ISCO simulation demonstrated that MnO4- plume movement could be monitored in a qualitative manner using bulk conductivity tomograms, although chargeability was below sensitivity limits. We also examined changes to in-phase and quadrature electrical conductivity resulting from ion injection, MnO2 and Cl- production, and pH change during TCE and humate oxidation by MnO4- in homogeneous aqueous solutions and saturated porous media samples. Data from the homogeneous samples demonstrated that inversion of the sand tank resistivity data using a common Tikhonov regularization approach was insufficient to recover an accurate conductivity distribution within the tank. While changes to in-phase conductivity could be successfully modeled, quadrature conductivity values could not be directly related to TCE oxidation product or MnO4- concentrations at frequencies consistent with field induced polarization surveys, limiting the utility of quadrature conductivity for monitoring ISCO.
Duggan, Jeffrey; Ren, Bailuo; Mao, Yan; Chen, Lin-Zhi; Philip, Elsy
2016-09-01
A refinement of protein LC-MS bioanalysis is to use predigestion immunoaffinity capture to extract the drug from matrix prior to digestion. Because of their increased sensitivity, such hybrid assays have been successfully validated and applied to a number of clinical studies; however, they can also be subject to potential interferences from antidrug antibodies, circulating ligands or other matrix components specific to patient populations and/or dosed subjects. The purpose of this paper is to describe validation experiments that measure immunocapture efficiency, digestion efficiency, matrix effect and selectivity/specificity that can be used during method optimization and validation to test the resistance of the method to these potential interferences. The designs and benefits of these experiments are discussed in this report using an actual assay case study.
Wright, Douglas L.; McGraw, Robert; Rosner, Daniel E.
2001-04-15
We extendthe application of moment methods to multivariate suspended particle population problems-those for which size alone is insufficient to specify the state of a particle in the population. Specifically, a bivariate extension of the quadrature method of moments (QMOM) (R. McGraw, Aerosol Sci. Technol. 27, 255 (1997)) is presented for efficiently modeling the dynamics of a population of inorganic nanoparticles undergoing simultaneous coagulation and particle sintering. Continuum regime calculations are presented for the Koch-Friedlander-Tandon-Rosner model, which includes coagulation by Brownian diffusion (evaluated for particle fractal dimensions, D(f), in the range 1.8-3) and simultaneous sintering of the resulting aggregates (P. Tandon and D. E. Rosner, J. Colloid Interface Sci. 213, 273 (1999)). For evaluation purposes, and to demonstrate the computational efficiency of the bivariate QMOM, benchmark calculations are carried out using a high-resolution discrete method to evolve the particle distribution function n(nu, a) for short to intermediate times (where nu and a are particle volume and surface area, respectively). Time evolution of a selected set of 36 low-order mixed moments is obtained by integration of the full bivariate distribution and compared with the corresponding moments obtained directly using two different extensions of the QMOM. With the more extensive treatment, errors of less than 1% are obtained over substantial aerosol evolution, while requiring only a few minutes (rather than days) of CPU time. Longer time QMOM simulations lend support to the earlier finding of a self-preserving limit for the dimensionless joint (nu, a) particle distribution function under simultaneous coagulation and sintering (Tandon and Rosner, 1999; D. E. Rosner and S. Yu, AIChE J., 47 (2001)). We demonstrate that, even in the bivariate case, it is possible to use the QMOM to rapidly model the approach to asymptotic behavior, allowing an immediate assessment of
LC-MS at core of university-industry link
Linding, Rune
2013-01-01
LC-MS at core of university-industry link Thermo Fisher Scientific (TFS) and the Department of Systems Biology at the Technical University of Denmark, (DTU), have formed a collaboration to pursue breakthroughs in the understanding of how cellular protein networks drive important diseases......, equipped with the latest LC-MS technology, including the TFS Orbitrap Fusion Tribrid LC-MS system that offers unprecedented depth of analysis of biological samples. ‘‘Studying the dynamic rewiring of cellular signaling networks requires state-ofthe-art mass spectrometry,’’ said DTU’s Professor Rune Linding...... (Fig. 8). ‘‘The Orbitrap Fusion system enables us to push the boundaries and to analyze completely new avenues of cellular decision processes, and to perform genome-scale studies of how the dynamics in these networks affect cell behavior. This is crucial, as it is now clear that the progression...
A Review and Modern Approach to LC Ladder Synthesis
Alexander J. Casson
2011-01-01
Full Text Available Ultra low power circuits require robust and reliable operation despite the unavoidable use of low currents and the weak inversion transistor operation region. For analogue domain filtering doubly terminated LC ladder based filter topologies are thus highly desirable as they have very low sensitivities to component values: non-exact component values have a minimal effect on the realised transfer function. However, not all transfer functions are suitable for implementation via a LC ladder prototype, and even when the transfer function is suitable the synthesis procedure is not trivial. The modern circuit designer can thus benefit from an updated treatment of this synthesis procedure. This paper presents a methodology for the design of doubly terminated LC ladder structures making use of the symbolic maths engines in programs such as MATLAB and MAPLE. The methodology is explained through the detailed synthesis of an example 7th order bandpass filter transfer function for use in electroencephalogram (EEG analysis.
Design of Dual Bandpass and Bandreject LC Ladder Filters
J. Hospodka
2006-09-01
Full Text Available This paper deals with the design of two-passband bandpass and two-stopband bandreject LC ladder filters. The design method is based on the special dual frequency transformation that transforms normalized lowpass to either bandpass with two passbands or to bandreject with two stopbands that are specified by four cutoff frequencies. The paper shows analytical solution relating these four cutoff frequencies to parameters of dual frequency transformation. It enables a direct computation of dual band LC filter elements from a normalized lowpass filter by means of simple relations. These relations have been implemented in the mathematical program Maple (TM as new user functions. They are supposed to be used as an enhancement of Syntfil package which is intended for analog filter design in program Maple. Specific application is shown on an example of the two-passband bandpass LC filter design.
Design of a LC-tuned magnetically suspended rotating gyroscope
Jin, Lichuan; Zhang, Huaiwu; Zhong, Zhiyong
2011-04-01
A inductor-capacitor (LC) tuned magnetically suspended rotating gyroscope prototype is designed and analyzed. High permeability ferrite cores are used for providing suspension force, and the rotation system is designed using the switched reluctance motor (SRM) principle. According to the LC-tuned principle, magnetic suspension force expression has been derived. The electromagnetic properties of the gyroscope are simulated by the Ansoft Maxwell software. And our result is expected to be able to serve as a prototype of micro-electromechanical system (MEMS) magnetically suspended rotating gyroscope in future practical applications.
Mutual couling reduction using a lumped LC circuit
Thaysen, Jesper; Jakobsen, Kaj Bjarne
2004-01-01
A technique to reduce the mutual coupling between two Planar Inverted F Antennas (PIFA) is presented in this paper. By the use of a parallel LC circuit it is possible to reduce the mutual coupling between two antennas. This results in a 16 % improvement in the radiation efficiency.......A technique to reduce the mutual coupling between two Planar Inverted F Antennas (PIFA) is presented in this paper. By the use of a parallel LC circuit it is possible to reduce the mutual coupling between two antennas. This results in a 16 % improvement in the radiation efficiency....
LC and ferromagnetic resonance in soft/hard magnetic microwires
Tian, Bin, E-mail: milesbintian@gmail.com [Wuhan Institute of Technology, 430073 Wuhan (China); Institute of Materials Science of Madrid, CSIC, 28049 Madrid (Spain); Vazquez, Manuel [Institute of Materials Science of Madrid, CSIC, 28049 Madrid (Spain)
2015-12-01
The magnetic behavior of soft/hard biphase microwires is introduced here. The microwires consist of a Co{sub 59.1}Fe{sub 14.8}Si{sub 10.2}B{sub 15.9} soft magnetic nucleus and a Co{sub 90}Ni{sub 10} hard outer shell separated by an intermediate insulating Pyrex glass microtube. By comparing the resistance spectrums of welding the ends of metallic core (CC) or welding the metallic core and outer shell (CS) to the connector, it is found that one of the two peaks in the resistance spectrum is because the LC resonance depends on the inductor and capacitors in which one is the capacitor between the metallic core and outer shell, and the other is between the outer shell and connector. Correspondingly, another peak is for the ferromagnetic resonance of metallic core. After changing the capacitance of the capacitors, the frequency of LC resonance moves to high frequency band, and furthermore, the peak of LC resonance in the resistance spectrum disappeared. These magnetostatically coupled biphase systems are thought to be of large potential interest as sensing elements in sensor devices. - Graphical abstract: By comparing the resistance spectrums of welding the ends of metallic core (CC) or welding the metallic core and outer shell (CS) to the connector, it is found that one of the two peaks in the resistance spectrum is because of the LC resonance depending on the inductor and capacitors. Correspondingly, another peak is for the ferromagnetic resonance of metallic core. After changing the capacitance of the capacitors, the frequency of LC resonance moves to high frequency band, and furthermore, the peak of LC resonance in the resistance spectrum disappeared. - Highlights: • The two peaks spectra of multilayer microwires, CoFeSiB/CoNi, with magnetic biphase behavior have been reported. • One of the two absorption peaks is because of the ferromagnetic resonance of metallic core. • The other absorption peak is because of the LC resonance which depends on the capacitors
A.S.J.AL-SAIF; 朱正佑
2003-01-01
The traditional differential quadrature method was improved by using the upwind difference scheme for the convectiveterms to solve the coupled two-dimensional incompressible Navier-stokes equations and heat equation. The new method was comparedwith the conventional differential quadrature method in the aspects of convergence and accuracy. The results show that the newmethod is more accurate, and has better convergence than the conventional differential quadrature method for numerically computingthe steady-state solution.
基于集成压控振荡器的调频电路仿真分析%FM Circuit Design and Simulation Analysis Based on Integrated VCO
霍然; 叶建芳
2014-01-01
LM566是一种积分-施密特触发电路型的单片集成 VCO 芯片，在调频电路的教学中作为调制器和解调器，通过对其芯片的仿真，可以在软件平台形象的展示其工作特点，便于定量分析。由于Multisim元件库里没有LM566所需模型，为实现LM566在Multisim12仿真环境中的建模，首先，运用Multisim元件库中现有的基本元件模型，构建LM566芯片内部结构；然后，对外围调频电路的静态工作方式和动态工作方式的分析；最后，实验结果表明，给出的芯片模型能够客观的描述LM566的基本特性，为运用该芯片完成包括调频电路在内的各种功能电路的仿真分析奠定了基础，有效扩展了Multisim仿真软件的使用范围，具有一定的借鉴意义。%LM566 is a kind of Monolithic integrated VCO chips of integral – schmidt trigger circuit type. It plays the role of mod-ulator and demodulator in the FM teaching. By simulation of its chip, the feature of its work can be vitally showed on the software platform, which is convenient for conducting quantitative analysis. Since there are not any models in the Multisim library that LM566 requires, in order to build up the LM566 modeling in Multisim12 simulation environment, the paper firstly establishes LM566’s chip internal structure. Then it analyzes the static and dynamic work of peripheral frequency modulation circuit.; it is indicated in the end that the chips model provided can objectively describe the basic character of LM566. It laids a solid founda-tion for chips using to complete simulation analysis of various functional circuit like FM and effectively expands Multisim’s range of application. So it has certain reference significe.
A New LC-MS Interface: Laser Spray
Kenzo Hiraoka
2001-01-01
@@ A new LC - MS interface was developed.Strong ion signals were obtained when aqueous or water/methanol sample solution effusing out of the stainless steel capillary was irradiated by the focused infrared laser.Generally, the ion signals obtained by this method, laser spray, are greater than those by electrospray, especially in the negative- mode operation.
LC-PCN: The Load Control PCN Solution
Westberg, L.; Bhargava, A.; Bader, A.; Karagiannis, G.; Westberg, L.; Bhargava, A.; Bader, A.; Karagiannis, G.
2007-01-01
There is an increased interest of simple and scalable resource provisioning solution for Diffserv network. The Load Control PCN (LC-PCN) addresses the following issues: o Admission Control for real time data flows in stateless Diffserv Domains o Flow Termination: Termination of flows in case of e
Expectations from LHC and LC on Top Physics
Cobal, M
2005-01-01
The current status of top quark studies at the Large Hadron Collider (LHC) and at the Linear Collider (LC) is summarized. Expectations on the measurements of the top mass, couplings and decays, of the top spin polarization and of the single top production are here reviewed.
A compact, all solid-state LC high voltage generator.
Fan, Xuliang; Liu, Jinliang
2013-06-01
LC generator is widely applied in the field of high voltage generation technology. A compact and all solid-state LC high voltage generator based on saturable pulse transformer is proposed in this paper. First, working principle of the generator is presented. Theoretical analysis and circuit simulation are used to verify the design of the generator. Experimental studies of the proposed LC generator with two-stage main energy storage capacitors are carried out. And the results show that the proposed LC generator operates as expected. When the isolation inductance is 27 μH, the output voltage is 1.9 times larger than the charging voltage on single capacitor. The multiplication of voltages is achieved. On the condition that the primary energy storage capacitor is charged to 857 V, the output voltage of the generator can reach to 59.5 kV. The step-up ratio is nearly 69. When self breakdown gas gap switch is used as main switch, the rise time of the voltage pulse on load resistor is 8.7 ns. It means that the series-wound inductance in the discharging circuit is very small in this system. This generator can be employed in two different applications.
LC-MS characterization of constituents of mesquite flour
Using an LC-MS method in conjunction with two complementary types of chromatographic retention modes—namely reversed phase and aqueous normal phase (ANP)—various compounds present in mesquite flour extracts were identified. Because of the diverse types of chemical constituents found in such natural ...
无
2007-01-01
As a part of the ongoing search for new constituents of Stemona species in China, chemical investigation of Stemona sessilifolia, a plant used in the traditional Chinese medicine to treat respiratory disorders, was carried out. To identify the chemical components rapidly, a selected sample of S. sessilifolia containing bibenzyls was tested using LC-ESIMS and analyzed further using stop-flow LC-UV-NMR, which was sensitive for the detection of the main constituents. LC microfractions were collected using the LC-UV-NMR technique and HR-EIMS off-line analysis was carried out on the collected fractions. This chemical screening strategy allowed for the on-line identification of the main constituents of S. sessilifolia and provided information that was useful for a further peak-guided isolation procedure.Using these methods, four bibenzyls were isolated: two known compounds, 3,5-dihydroxy-4-methyl bibenzyl(1) and 3,5-dihydroxy-2'-methoxy-4-methyl bibenzyl ( 2 ), and two novel compounds, 3, 3'-dihydroxy-5, 6'-dimethoxy bibenzyl (3) and 3,5-dihydroxy-2' ,5'-dimethoxy bibenzyl (4).
李旺; 唐俊
2013-01-01
在频率源芯片窄带应用时,输出信号有较好的积分均方根抖动性能(RMS jitter),需要压控振荡器(VCO)有较出色的相噪特性.通过分析VCO的结构特点,确定电感是影响片上VCO相位噪声的关键性因素,通过HFSS软件建模的方式,将高品质因素(Q)值的键合线电感引入到片上VCO设计中.采用0.18 μm SiGe BiC-MOS工艺,设计了整块频率源芯片,并着重优化了VCO输出信号的相位噪声.经过实测,在开环状态下,VCO输出信号为2.2 GHz,在1 MHz频偏处的相位噪声为-136 dBc/Hz;在环路带宽80 kHz,芯片输出信号相噪2.2GHz时,整颗芯片输出信号的带内本底噪声为-220 dBc/Hz,杂散为-70 dBc,积分均方根抖动为207.666 fs.
A Ka-band GaAs MHEMT VCO MMIC with Low Phase Noise%Ka波段低相位噪声GaAs MHEMT单片压控振荡器
王维波; 王志功; 张斌; 康耀辉; 吴礼群; 杨乃彬
2009-01-01
报道了一种低相位噪声VCO MMIC芯片,采用传统的源端反馈形成负阻来消除谐振回路中的寄生电阻,通过合理的输出匹配实现起振条件并抑制谐波,利用南京电子器件研究所0.15μm GaAs MHEMT工艺,研制的Ka波段GaAs MHEMT压控振荡器,典型振荡频率为39.34 GHz,频率变化范围38.6～41.3 GHz之间,调谐带宽2.7 GHz,典型输出功率6.97 dBm,频偏100 kHZ,相位噪声为-81.1 dBc/HZ.
Avila, Gustavo; Carrington, Tucker
2011-08-01
In this paper we propose and test a method for computing numerically exact vibrational energy levels of a molecule with six atoms. We use a pruned product basis, a non-product quadrature, the Lanczos algorithm, and the exact normal-coordinate kinetic energy operator (KEO) with the πtμπ term. The Lanczos algorithm is applied to a Hamiltonian with a KEO for which μ is evaluated at equilibrium. Eigenvalues and eigenvectors obtained from this calculation are used as a basis to obtain the final energy levels. The quadrature scheme is designed, so that integrals for the most important terms in the potential will be exact. The procedure is tested on C2H4. All 12 coordinates are treated explicitly. We need only ˜1.52 × 108 quadrature points. A product Gauss grid with which one could calculate the same energy levels has at least 5.67 × 1013 points.
分维自适应稀疏网格积分非线性滤波器%Dimension-wise Adaptive Spare Grid Quadrature Nonlinear Filter
徐嵩; 孙秀霞; 刘树光; 刘希; 蔡鸣
2014-01-01
For nonlinear discrete systems with addictive Gaus-sian noises, a new quadrature filter is proposed, which can fix sample points according to each dimension0s nonlinear function, respectively. In order to match higher-order terms of the nonlin-ear function0s Taylor expanding with reusing the sample points matching lower-order ones, an adaptive sampled multi variable quadrature rule is designed based on the embedded Gaussian sampled quadrature and the spare grid quadrature (SGQ) for-mula. A group of effective data structures and traversal algo-rithms are proposed for the sampled quadrature rule to be used for calculating the predict expectations of the states and mea-surements with their covariances. This filter could not only fix sampled points for different dimensions separately, but also reuse these points and their weights completely, thus enhancing the ef-ficiency of the filter. This filter achieves a higher accuracy than the unscented Kalman filter (UKF) , more effciency than the fixed SGQ filter, as well as generalized form of these two filters. The calculating cost of adaptive steps is much less than comput-ing the function sampled values. Simulations also validates the accuracy and effciency of this filter.%针对含加性高斯噪声的非线性离散系统，提出了可分别根据各维状态及量测方程的非线性函数特性来确定采样点及其权重的积分滤波器。设计了基于嵌入式高斯采样积分和稀疏网格法则的自适应多变量采样积分方法，可在匹配函数高阶泰勒展开项时，利用低阶采样点，提出了高效的数据结构和遍历算法，便于采用该积分方法分别估计系统状态/量测的预测均值和协方差矩阵。该滤波器既能根据各维非线性函数的特性确定采样点，又实现了对采样值和权重的完全复用，保证了算法效率。理论分析和仿真表明，该滤波算法中自适应调整的运算量小于计算非线性函数采样值。该滤
Frequency jumps in single chip microwave LC oscillators
Gualco, Gabriele; Grisi, Marco; Boero, Giovanni, E-mail: giovanni.boero@epfl.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015 (Switzerland)
2014-12-15
We report on the experimental observation of oscillation frequency jumps in microwave LC oscillators fabricated using standard complementary metal-oxide-semiconductor technologies. The LC oscillators, operating at a frequency of about 20 GHz, consist of a single turn planar coil, a metal-oxide-metal capacitor, and two cross-coupled metal-oxide-semiconductor field effect transistors used as negative resistance network. At 300 K as well as at 77 K, the oscillation frequency is a continuous function of the oscillator bias voltage. At 4 K, frequency jumps as large as 30 MHz are experimentally observed. This behavior is tentatively attributed to the emission and capture of single electrons from defects and dopant atoms.
LC-MS at core of university-industry link
Linding, Rune
2013-01-01
LC-MS at core of university-industry link Thermo Fisher Scientific (TFS) and the Department of Systems Biology at the Technical University of Denmark, (DTU), have formed a collaboration to pursue breakthroughs in the understanding of how cellular protein networks drive important diseases...... by exploiting liquid chromatography coupled to mass spectrometry (LC-MS). TFS will provide early access to new technology and designs, and DTU proteomics scientists will rovide feedback and collaborate on new applications. The centerpiece of this collaboration is a new proteomics laboratory in Lyngby, Denmark.......’’ ‘‘We are immensely pleased to be working with this talented and motivated team of scientists,’’ said Iain Mylchreest, vice president, research and development, life science mass spectrometry, TFS. ‘‘We share with them the objective of pushing the limits of science to make the world a better place...
File list: Unc.PSC.10.AllAg.EpiLC [Chip-atlas[Archive
Full Text Available Unc.PSC.10.AllAg.EpiLC mm9 Unclassified Pluripotent stem cell EpiLC SRX1074910,SRX1...074907 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.PSC.10.AllAg.EpiLC.bed ...
File list: Unc.PSC.05.AllAg.EpiLC [Chip-atlas[Archive
Full Text Available Unc.PSC.05.AllAg.EpiLC mm9 Unclassified Pluripotent stem cell EpiLC SRX1074910,SRX1...074907 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.PSC.05.AllAg.EpiLC.bed ...
File list: Unc.PSC.50.AllAg.EpiLC [Chip-atlas[Archive
Full Text Available Unc.PSC.50.AllAg.EpiLC mm9 Unclassified Pluripotent stem cell EpiLC SRX1074910,SRX1...074907 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.PSC.50.AllAg.EpiLC.bed ...
File list: Unc.PSC.20.AllAg.EpiLC [Chip-atlas[Archive
Full Text Available Unc.PSC.20.AllAg.EpiLC mm9 Unclassified Pluripotent stem cell EpiLC SRX1074910,SRX1...074907 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.PSC.20.AllAg.EpiLC.bed ...
More than a Library for Congress: Making LC the Nation's Library.
Mason, Marilyn Gell
1993-01-01
Discusses designating the Library of Congress (LC) as a national library. Topics addressed include problems with Congress; costs of serving the information needs of Congress; funds for electronic conversion; access to LC resources; user fees; reallocating federal library aid; and governance of LC. (LRW)
A splice variant of PGRP-LC required for expression of antimicrobial peptides in Anopheles gambiae
HUI LIN; LINGMIN ZHANG; CORALIA LUNA; NGO T.HOA; LIANGBIAO ZHENG
2007-01-01
Members of the peptidoglycan recognition protein (PGRP) family play essential roles in different manifestations of immune responses in insects. PGRP-LC, one of seven members of this family in the malaria vector Anopheles gambiae produced several spliced variants. Here we show that PGRP-LC, and not other members of the PGRP family nor the six members of the Gram-negative binding protein families, is required for the expression of antimicrobial peptide genes (such as CEC1 and GAM1) under the control of the Imd-Rel2 pathway in an A. gambiae cell line, 4a3A. PGRP-LC produces many splice variants that can be classified into three sub-groups (LC1, LC2 and LC3), based on the carboxyl terminal sequences. RNA interference against one LC1 sub-group resulted in dramatic reduction of CEC1 and GAM1. Over-expression of LC1 a and to a lesser extent LC3a (a member of the LC1 and LC3 sub-group, respectively) in the 4a3A cell line enhances the expression of CEC1 and GAM1. These results demonstrate that the LC1-subgroup splice variants are essential for the expression of CEC1 and GAM1 in A. gambiae cell line.
Proposal for axion dark matter detection using an LC circuit.
Sikivie, P; Sullivan, N; Tanner, D B
2014-04-04
We show that dark matter axions cause an oscillating electric current to flow along magnetic field lines. The oscillating current induced in a strong magnetic field B0 produces a small magnetic field Ba. We propose to amplify and detect Ba using a cooled LC circuit and a very sensitive magnetometer. This appears to be a suitable approach to searching for axion dark matter in the 10(-7) to 10(-9) eV mass range.
Operational Simulation of LC Ladder Filter Using VDTA
Praveen Kumar
2017-01-01
Full Text Available In this paper, a systematic approach for implementing operational simulation of LC ladder filter using voltage differencing transconductance amplifier is presented. The proposed filter structure uses only grounded capacitor and possesses electronic tunability. PSPICE simulation using 180 nm CMOS technology parameter is carried out to verify the functionality of the presented approach. Experimental verification is also performed through commercially available IC LM13700/NS. Simulations and experimental results are found to be in close agreement with theoretical predictions.
Number-Phase Quantization Scheme for L-C Circuit
无
2007-01-01
For a mesoscopic L-C circuit, besides the Louisell's quantization scheme in which electric charge q and electric current Ⅰ are respectively quantized as the coordinate operator Q and momentum operator P, in this paper we propose a new quantization scheme in the context of number-phase quantization through the standard Lagrangian formalism. The comparison between this number-phase quantization with the Josephson junction's Cooper pair numberphase-difference quantization scheme is made.
LC and ferromagnetic resonance in soft/hard magnetic microwires
Tian, Bin; Vazquez, Manuel
2015-12-01
The magnetic behavior of soft/hard biphase microwires is introduced here. The microwires consist of a Co59.1Fe14.8Si10.2B15.9 soft magnetic nucleus and a Co90Ni10 hard outer shell separated by an intermediate insulating Pyrex glass microtube. By comparing the resistance spectrums of welding the ends of metallic core (CC) or welding the metallic core and outer shell (CS) to the connector, it is found that one of the two peaks in the resistance spectrum is because the LC resonance depends on the inductor and capacitors in which one is the capacitor between the metallic core and outer shell, and the other is between the outer shell and connector. Correspondingly, another peak is for the ferromagnetic resonance of metallic core. After changing the capacitance of the capacitors, the frequency of LC resonance moves to high frequency band, and furthermore, the peak of LC resonance in the resistance spectrum disappeared. These magnetostatically coupled biphase systems are thought to be of large potential interest as sensing elements in sensor devices.
On the impedance of infinite LC ladder networks
Klimo, Paul
2017-01-01
The subject of electrical impedance is on the syllabi of most undergraduate courses in physics and electrical engineering. For example, Richard Feynman in his famous undergraduate text Lectures on Physics shows how to calculate the impedance of an infinite LC ladder. However, the formula he obtains has no useful physical interpretation if considered in the steady state frequency domain. In fact the value of this impedance becomes infinite unless one assumes that the energy flow along the infinite LC ladder is spatially uniform and in one direction only. This ad-hoc assumption, which renders the solution non-causal, is entirely unnecessary if the problem is considered in the time domain. It is important for students to appreciate that the concept of impedance works well only in dissipative circuits where the effects of transients are largely short lived. The purpose of this paper is to show that the same problem treated in the time domain by the Laplace transform method provides a qualitatively different and more satisfying explanation. We show that the current response of an infinite LC ladder, which is in the zero state before a causal harmonic driving voltage is applied, contains a significant non-harmonic component. This component, which is present in addition to the forced harmonic waveform, decays only very slowly and extracts an infinite amount of energy from the source.
LC-MS-Based Metabolic Fingerprinting of Aqueous Humor
Dmuchowska, Diana Anna; Krasnicki, Pawel; Wojnar, Malgorzata; Skowronska, Aleksandra; Mariak, Zofia
2017-01-01
Aqueous humor (AH) is a transparent fluid which fills the anterior and posterior chambers of the eye. It supplies nutrients and removes metabolic waste from avascular tissues in the eye. Proper homeostasis of AH is required to maintain adequate intraocular pressure as well as optical and refractive properties of the eye. Application of metabolomics to study human AH may improve knowledge about the molecular mechanisms of eye diseases. Until now, global analysis of metabolites in AH has been mainly performed using NMR. Among the analytical platforms used in metabolomics, LC-MS allows for the highest metabolome coverage. The aim of this study was to develop a method for extraction and analysis of AH metabolites by LC-QTOF-MS. Different protocols for AH preparation were tested. The best results were obtained when one volume of AH was mixed with one volume of methanol : ethanol (1 : 1). In the final method, 2 µL of extracted sample was analyzed by LC-QTOF-MS. The method allowed for reproducible measurement of over 1000 metabolic features. Almost 250 metabolites were identified in AH and assigned to 47 metabolic pathways. This method is suitable to study the potential role of amino acids, lipids, oxidative stress, or microbial metabolites in development of ocular diseases.
2008 LC18: a potentially unstable Neptune Trojan
Horner, J; Bannister, M T; Francis, P
2012-01-01
The recent discovery of the first Neptune Trojan at the planet's trailing (L5) Lagrange point, 2008 LC18, offers an opportunity to confirm the formation mechanism of a member of this important tracer population for the Solar system's dynamical history. We tested the stability of 2008 LC18's orbit through a detailed dynamical study, using test particles spread across the \\pm3{\\sigma} range of orbital uncertainties in a, e, i and {\\Omega}. This showed that the wide uncertainties of the published orbit span regions of both extreme dynamical instability, with lifetimes 1 Gyr lifetimes). The stability of 2008 LC18's clones is greatly dependent on their semi-major axis and only weakly correlated with their eccentricity. Test particles on orbits with an initial semi-major axis less than 29.91 AU have dynamical half-lives shorter than 100 Myr; in contrast, particles with an initial semi-major axis greater than 29.91 AU exhibit such strong dynamical stability that almost all are retained over the 1 Gyr of our simulat...