WorldWideScience

Sample records for hf radio communication

  1. A new wideband HF technique for MHz-bandwidth spread-spectrum radio communications

    Science.gov (United States)

    Perry, B. D.

    1983-09-01

    The one-way results are seen as demonstrating that equalized MHz-bandwidth skywave HF channels can be achieved using long-range one-hop F-layer propagation paths. It has thus become possible to use direct-sequence pseudo-noise or coherent fast-frequency-hop signaling at HF with processing gains of several orders of magnitude for teletype data rates. Possibilities are seen for using the spread spectrum in covert and/or jam-resistant communications. What is more, the equalized wideband HF channel is not subject to the fading caused by multiple propagation modes; as a consequence, it is substantially more reliable than the traditional narrow-band HF channel. Conversely, reliability comparable to traditional HF can be attained at greatly reduced signal margins. Since the time stability of the wideband HF channel is of the order of 10 s, very little channel-transmission time is needed for initializing and maintaining the equalizer. It is noted that probe signals similar to the channel-measuring waveform described here or spread-spectrum training sequences at the beginning of each message are adequate. Results from the 1982 two-way experimentation show that N(omega) is not reciprocal between terminals 2000 km apart.

  2. Research on Multi-Layer Distributed HF Radio Network Structure

    Institute of Scientific and Technical Information of China (English)

    Hui Dai; Chun-Jiang Wang; Quan Yu

    2008-01-01

    High frequency (HF) transmission is an important communication techniques. However, conventional point-to-point transmission can be easily destroyed, which limits its utilization in practice. HF networking communication has the capability against demolishment. The network structure is one of the key factors for HF networking communication. In this paper, a novel analysis method of the network connectedness based on the eigenvalue is derived, and a multi-layer distributed HF radio network structure is proposed. Both the theore tical analysis and the computer simulation results verify that the application of the proposed network structure in the HF radio communication can improve the anti demolishment ability of the HF network efficiently.

  3. HF radio systems and circuits

    CERN Document Server

    Sabin, William

    1998-01-01

    A comprehensive reference for the design of high frequency communications systems and equipment. This revised edition is loaded with practical data, much of which cannot be found in other reference books. Its approach to the subject follows the needs of an engineer from system definition and performance requirements down to the individual circuit elements that make up radio transmitters and receivers. The accompanying disk contains updated software on filters, matching networks and receiver analysis. SciTech Publishing also provides many other products related to Communication Systems Design.

  4. General concepts of modern HF communications

    Science.gov (United States)

    Aarons, Jules

    Both conceptual and hardware advancements have led to substantial systems developments in military HF communications; the former encompass coding and error correction techniques for security, in order to minimize propagation and interference, while the latter prominently include digital equipment permitting the selection of a frequency for a particular path and propagation mode, as well as modulation selection. Propagation-related advancements involve better statistical models as well as advancements in short-term forecasting methods responsive to changes in solar-geophysical parameters. Adaptive HF systems have been developed for meteor-scatter radio communications.

  5. Aspects of HF radio propagation

    Directory of Open Access Journals (Sweden)

    Stephane Saillant

    2009-06-01

    Full Text Available

    radio systems. From the point of view Working Group 2 of the COST 296 Action, interest lies with effects associated

    with propagation via the ionosphere of signals within the HF band. Several aspects are covered in this paper:

    a The directions of arrival and times of flight of signals received over a path oriented along the trough have

    been examined and several types of propagation effects identified. Of particular note, combining the HF observations

    with satellite measurements has identified the presence of irregularities within the floor of the trough that

    result in propagation displaced from the great circle direction. An understanding of the propagation effects that

    result in deviations of the signal path from the great circle direction are of particular relevance to the operation

    of HF radiolocation systems.

    b Inclusion of the results from the above mentioned measurements into a propagation model of the northerly

    ionosphere (i.e. those regions of the ionosphere located poleward of, and including, the mid-latitude trough

    and the use of this model to predict the coverage expected from transmitters where the signals impinge on the

    northerly ionosphere

  6. Commercial Radio as Communication.

    Science.gov (United States)

    Rothenbuhler, Eric W.

    1996-01-01

    Compares the day-to-day work routines of commercial radio with the principles of a theoretical communication model. Illuminates peculiarities of the conduct of communication by commercial radio. Discusses the application of theoretical models to the evaluation of practicing institutions. Offers assessments of commercial radio deriving from…

  7. Ionosphere and Radio Communication

    Indian Academy of Sciences (India)

    Saradi Bora

    2017-02-01

    The Earth's ionosphere consists of plasma produced by thephotoionization of thin upper atmospheric gases by UV raysand photons of short wavelength from the sun. The upperionosphere is used for radio communication and navigationas it reflects long, medium, as well as short radio waves. Sincesolar radiation is the main cause of the existence of ionosphere,any variation in the radiations can affect the entireradio communication system. This article attempts to brieflyintroduce the readers to the study of ionosphere in the contextof its use as a radio reflector, with particular reference toIndia.

  8. Albanian: Basic Radio Communications.

    Science.gov (United States)

    Defense Language Inst., Washington, DC.

    This volume has been designed as a supplement to a course in Albanian developed by the Defense Language Institute. The emphasis in this text is placed on radio communications instruction. The volume is divided into five exercises, each of which contains a vocabulary, dictation, and an air-to-ground communications procedure conducted in Albanian…

  9. Physics of the Geospace Response to Powerful HF Radio Waves

    Science.gov (United States)

    2012-10-31

    studies of the response of the Earth’s space plasma to high-power HF radio waves from the High-frequency Active Auroral Research Program ( HAARP ...of HF heating and explored to simulate artificial ducts. DMSP- HAARP experiments revealed that HF-created ion outflows and artificial density ducts...in the topside ionosphere appeared faster than predicted by the models, pointing to kinetic (suprathermal) effects. CHAMP/GRACE- HAARP experiments

  10. A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the influenc

  11. A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the

  12. Ionosphere research with a HF/MF cubesat radio instrument

    Science.gov (United States)

    Kallio, Esa; Aikio, Anita; Alho, Markku; Fontell, Mathias; Harri, Ari-Matti; Kauristie, Kirsti; Kestilä, Antti; Koskimaa, Petri; Mäkelä, Jakke; Mäkelä, Miika; Turunen, Esa; Vanhamäki, Heikki; Verronen, Pekka

    2017-04-01

    New technology provides new possibilities to study geospace and 3D ionosphere by using spacecraft and computer simulations. A type of nanosatellites, CubeSats, provide a cost effective possibility to provide in-situ measurements in the ionosphere. Moreover, combined CubeSat observations with ground-based observations gives a new view on auroras and associated electromagnetic phenomena. Especially joint and active CubeSat - ground based observation campaigns enable the possibility of studying the 3D structure of the ionosphere. Furthermore using several CubeSats to form satellite constellations enables much higher temporal resolution. At the same time, increasing computation capacity has made it possible to perform simulations where properties of the ionosphere, such as propagation of the electromagnetic waves in the medium frequency, MF (0.3-3 MHz) and high frequency, HF (3-30 MHz), ranges is based on a 3D ionospheric model and on first-principles modelling. Electromagnetic waves at those frequencies are strongly affected by ionospheric electrons and, consequently, those frequencies can be used for studying the plasma. On the other hand, even if the ionosphere originally enables long-range telecommunication at MF and HF frequencies, the frequent occurrence of spatiotemporal variations in the ionosphere disturbs communication channels, especially at high latitudes. Therefore, study of the MF and HF waves in the ionosphere has both a strong science and technology interests. We introduce recently developed simulation models as well as measuring principles and techniques to investigate the arctic ionosphere by a polar orbiting CubeSat whose novel AM radio instrument measures HF and MF waves. The cubesat, which contains also a white light aurora camera, is planned to be launched in late 2017 (http://www.suomi100satelliitti.fi/eng). The new models are (1) a 3D ray tracing model and (2) a 3D full kinetic electromagnetic simulation. We also introduce how combining of the

  13. Impact of transport layer protocols on the efficiency of special purpose radio-communications

    OpenAIRE

    NEDELJKOVIC LJUBISA S.

    2014-01-01

    The efficiency of special purpose radio-communications depends on transport layer protocols. Meny factors have an impact on special purpose radio-communications efficiency, as well as TCP and UDP protocols. This paper presents the transport protocols throughput analysis in the HF and VHF radio-communications versus RTT and packet error rate probability. This paper considers a posibility of the application of TCP and UDP protocols in special purpose radio-communications. The following factors ...

  14. Impact of famous CEDAR, GEM and ISTP geomagnetic Storms on HF Radio Propagation

    Science.gov (United States)

    Blagoveshchensky, D.; Sergeeva, M.

    The mighty geomagnetic storms due to the extraordinary Sun s activity cause as a rule some impacts in these areas radiation effects on human and satellites commercial airlines outages electric power and other geomagnetic effects navigation and communication GPS effects ionospheric disturbances HF communication effects Therefore our scientific understanding of this activity is very important Joint efforts for example within the framework of the CAWSES enable progress in our ability to i identify critical inputs to specify the geospace environment at a level needed to minimize impacts on technology human society and life and ii support the development of robust models that predict conditions in geospace based on understanding of the Sun-Earth system and all of its interacting components In this study influence of 14 geomagnetic storms from a list of CEDAR GEM and ISTP storms within 1997-99 on radio propagation conditions have been investigated These conditions were estimated through variations of the MOF and LOF the maximum and lowest operation frequencies on each path from three high-latitude HF radio paths of North-west Russia before during and after a storm It was shown that the storm impact on the ionosphere and radio propagation for each storm has an individual character Nevertheless the common character of the certain manifestations during storm-time was revealed For example the frequency range MOF - LOF is getting wider several hours before a storm then it is sharply narrow during a storm-time and further it is expanded again several

  15. Geospace ionosphere research with a MF/HF radio instrument on a cubesat

    Science.gov (United States)

    Kallio, E. J.; Aikio, A. T.; Alho, M.; Fontell, M.; van Gijlswijk, R.; Kauristie, K.; Kestilä, A.; Koskimaa, P.; Makela, J. S.; Mäkelä, M.; Turunen, E.; Vanhamäki, H.

    2016-12-01

    Modern technology provides new possibilities to study geospace and its ionosphere, using spacecraft and and computer simulations. A type of nanosatellites, CubeSats, provide a cost effective possibility to provide in-situ measurements in the ionosphere. Moreover, combined CubeSat observations with ground-based observations gives a new view on auroras and associated electromagnetic phenomena. Especially joint and active CubeSat - ground based observation campaigns enable the possibility of studying the 3D structure of the ionosphere. Furthermore using several CubeSats to form satellite constellations enables much higher temporal resolution. At the same time, increasing computation capacity has made it possible to perform simulations where properties of the ionosphere, such as propagation of the electromagnetic waves in the medium frequency, MF (0.3-3 MHz) and high frequency, HF (3-30 MHz), ranges is based on a 3D ionospheric model and on first-principles modelling. Electromagnetic waves at those frequencies are strongly affected by ionospheric electrons and, consequently, those frequencies can be used for studying the plasma. On the other hand, even if the ionosphere originally enables long-range telecommunication at MF and HF frequencies, the frequent occurrence of spatiotemporal variations in the ionosphere disturbs communication channels, especially at high latitudes. Therefore, study of the MF and HF waves in the ionosphere has both a strong science and technology interests. We present computational simulation results and measuring principles and techniques to investigate the arctic ionosphere by a polar orbiting CubeSat whose novel AM radio instrument measures HF and MF waves. The cubesat, which contains also a white light aurora camera, is planned to be launched in 2017 (http://www.suomi100satelliitti.fi/eng). We have modelled the propagation of the radio waves, both ground generated man-made waves and space formed space weather related waves, through the 3D

  16. Anomalous phenomena on HF radio paths during geomagnetic disturbances

    Science.gov (United States)

    Blagoveshchenskii, D. V.

    2016-07-01

    We analyze ionospheric oblique sounding data on three high-latitude and one high-latitude-midlatitude HF radio paths for February 15 and 16, 2014, when two substorms and one magnetic storm occurred. We investigate cases of anomalous propagation of signals: their reflection from sporadic layer Es, lateral reflections, type "M" or "N" modes, the presence of traveling ionospheric disturbances, and the diffusivity of signals and triplets. The most significant results are the following. In geomagnetically undisturbed times, sporadic Es-layers with reduced maximum observed frequencies (MOF Es) on three high-latitude paths were observed in both days. The values of MOF Es during disturbances are large, which leads to the screening of other oblique sounding signals reflected from the ionosphere. On all four paths, the most frequently traveling ionospheric disturbances due to the terminator were observed in quiet hours from 03:00 to 15:00 UT on the first day and from 06:00 to 13:00 UT on the second day of the experiment. In addition, both the sunset terminator and the magnetic storm on the high-latitude-mid-latitude path were found to generate traveling ionospheric disturbances jointly. No such phenomenon was found on high-latitude paths.

  17. New Adaptive Data Transmission Scheme Over HF Radio

    Directory of Open Access Journals (Sweden)

    Adil H. Ahmad

    2008-01-01

    Full Text Available Acceptable Bit Error rate can be maintained by adapting some of the design parameters such as modulation, symbol rate, constellation size, and transmit power according to the channel state.An estimate of HF propagation effects can be used to design an adaptive data transmission system over HF link. The proposed system combines the well known Automatic Link Establishment (ALE together with variable rate transmission system. The standard ALE is modified to suite the required goal of selecting the best carrier frequency (channel for a given transmission. This is based on measuring SINAD (Signal plus Noise plus Distortion to Noise plus Distortion, RSL (Received Signal Level, multipath phase distortion and BER (Bit Error Rate for each channel in the frequency list. Channel condition evaluation is done by two arrangements. In the first an FFT analysis is used where a pilot signal is transmitted over the channel, while the data itself is used in the second arrangement. Passive channel assessment is used to avoid bad channels hence limiting the frequency pool size to be used in the point to point communication and the time required for scanning and linking. An exchange of channel information between the transmitting and receiving stations is considered to select the modulation scheme for transmission. Mainly MPSK and MFSK are considered with different levels giving different data rate according to the channel condition. The results of the computer simulation have shown that when transmitting at a fixed channel symbol rate of 1200 symbol/sec, the information rate ranges from 2400 bps using 4FSK up to 3600 bps using 8PSK for SNR ranges from 11dB up to 26dB.

  18. Regulation of Wire and Radio Communication.

    Science.gov (United States)

    Federal Communications Commission, Washington, DC.

    This bulletin reviews early federal regulation of telegraphy, telephone, and radio communications, and the development of the Radio Acts of 1912 and 1927, the Communications Act of 1934, and the Communications Satellite Act of 1962. A large portion of the discussion focuses on the regulatory power and procedures of the Federal Communications…

  19. 49 CFR 220.45 - Radio communication shall be complete.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Radio communication shall be complete. 220.45... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.45 Radio communication shall be complete. Any radio communication which is not fully understood...

  20. Propagation Impact on Modern HF (High Frequency) Communications System Design

    Science.gov (United States)

    1986-03-01

    US Gvt Printing Office, Washington DC. Piggot, W.R., Rawer, K. (1972). URSI Handbook for lonogram Interpretation and... Handbook ", Communications Research Centre Report No. 1255, 1974. Widrow B., Mantey P.E., Griffiths L.J. and Goode B.B., "Adaptive Antenna Systems...implemented in modified form by the terminal node controller (TNC). In the U.S., Amateur Radio Relay League ( ARRL ) radio amateurs have held four annual

  1. Realistic Radio Communications in Pilot Simulator Training

    Science.gov (United States)

    Burki-Cohen, Judith; Kendra, Andrew J.; Kanki, Barbara G.; Lee, Alfred T.

    2000-01-01

    Simulators used for total training and evaluation of airline pilots must satisfy stringent criteria in order to assure their adequacy for training and checking maneuvers. Air traffic control and company radio communications simulation, however, may still be left to role-play by the already taxed instructor/evaluators in spite of their central importance in every aspect of the flight environment. The underlying premise of this research is that providing a realistic radio communications environment would increase safety by enhancing pilot training and evaluation. This report summarizes the first-year efforts of assessing the requirement and feasibility of simulating radio communications automatically. A review of the training and crew resource/task management literature showed both practical and theoretical support for the need for realistic radio communications simulation. A survey of 29 instructor/evaluators from 14 airlines revealed that radio communications are mainly role-played by the instructor/evaluators. This increases instructor/evaluators' own workload while unrealistically lowering pilot communications load compared to actual operations, with a concomitant loss in training/evaluation effectiveness. A technology review searching for an automated means of providing radio communications to and from aircraft with minimal human effort showed that while promising, the technology is still immature. Further research and the need for establishing a proof-of-concept are also discussed.

  2. Cognitive Radio Networks for Tactical Wireless Communications

    Science.gov (United States)

    2014-12-01

    APs work as wireless routers and form a wireless backbone network. The MSs can either access the BSs/APs directly, or use other MSs as multi-hop...Cognitive radio networks for tactical wireless communications Helen Tang; Susan Watson DRDC – Ottawa Research Centre Defence Research and...Development Canada Scientific Report DRDC-RDDC-2014-R185 December 2014 Cognitive radio networks for tactical wireless communications Helen Tang

  3. Radio communications with extra-terrestrial civilizations

    Science.gov (United States)

    Kotelnikov, V. A.

    1974-01-01

    Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.

  4. Intelligent Wireless Communication System Using Cognitive Radio

    Directory of Open Access Journals (Sweden)

    Asma Amraoui

    2012-04-01

    Full Text Available The increasing demand for wireless communication introduces efficient spectrum utilization challenge. To address this challenge, cognitive radio (CR is emerged as the key technology; which enables opportunistic access to the spectrum. CR is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not, and instantly move into vacant channels while avoiding occupied ones. This optimizes the use of available radio-frequency (RFspectrum while minimizing interference to other users. In this paper, we present a state of the art onthe use of Multi Agent Systems (MAS for spectrum access using cooperation and competition to solve the problem of spectrum allocation and ensure better management. Then we propose a new approach which uses the CR for improving wireless communication for a single cognitive radio mobile terminal (CRMT.

  5. 49 CFR 220.51 - Radio communications and signal indications.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Radio communications and signal indications. 220... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.51 Radio communications and signal indications. (a) No information may be...

  6. Antenna selection in a SIMO architecture for HF radio links

    Science.gov (United States)

    Erhel, Yvon; Lemur, Dominique; Oger, Martial; Le Masson, Jérôme

    2016-03-01

    This work takes place in the global design of a SIMO architecture (single input multiple output) for transhorizon radio links, aiming at a significant increase in the data rate when compared with standard modems based in general on a SISO scheme (single input single output). The project is subject to available space constraints at the receive end, involving mobile stations or onboard implementation. We consider solutions that appear as extensions of the compact and heterogeneous antenna array that we proposed previously: collocated antennas of different types are set up with the same phase center and present diversity in their polarization sensitivities to make array processing effective. Given the number NC of receive channels, we address the problem of selecting the most effective antennas in a set of NA possible candidates including monopoles, dipoles, loop antennas with various geometries, and orientations. The criterion to be maximized is the SIMO outage capacity, a quantity based on the statistical distribution of the SIMO Shannon capacity estimated for a large number of ionospheric channel realizations, each of them being quantified by its channel impulse response including the receive antenna directional responses. Results are presented in the context of a 1 × 2 SIMO structure: the identification of the two most effective antennas in a set of NA = 15 sensors indicates that the optimal structures involve two orthogonal horizontal dipoles or two vertical orthogonal loop antennas. In these conditions, the outage capacity reaches up to 2.23 bps/Hz, a value that significantly exceeds the performances of standard modems.

  7. Voice communications over packet radio networks

    Science.gov (United States)

    Seah, M. M.

    1985-03-01

    The use of packet virtual circuit technique for voice communications in military radio networks was investigated. The work was concerned with various aspects of networking which include network modeling, communications techniques, traffic analysis and network control. An attempt has been made to develop a simple yet efficient time slot assignment algorithm . This was analyzed under a variety of slot depths and networks topologies using computer simulation. The Erlang' B results were used to provide more insight into the channel characteristics of the packet radio networks. The capabilities of implementing TDMA/CDMA hybrid schemes in the system were scrutinized. A method to estimate the transmission capacity of the inter-node links was found. We demonstrate its effectiveness in controlling local congestion by computer simulation. Graphical results were presented to highlight the behavior of the proposed packet radio networks. We concluded that an appropriate link weight function would provide efficient and reliable network services.

  8. Spanish Basic Course: Radio Communications Procedures, USAF.

    Science.gov (United States)

    Defense Language Inst., Washington, DC.

    This guide to radio communication procedures is offered in Spanish and English as a means of securing a closer working relationship among United States Air Force personnel and Latin American aviators and technicians. Eight dialogues concerning routine flight procedures and aerospace technology are included. It is suggested that two rated students…

  9. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions

    Science.gov (United States)

    Sato, Yuka; Kumamoto, Atsushi; Katoh, Yuto; Shinbori, Atsuki; Kadokura, Akira; Ogawa, Yasunobu

    2016-05-01

    We report on the first simultaneous measurements of medium-high frequency (MF/HF) auroral radio emissions (above 1 MHz) by ground- and satellite-based instruments. Observational data were obtained by the ground-based passive receivers in Iceland and Svalbard, and by the Plasma Waves and Sounder experiment (PWS) mounted on the Akebono satellite. We observed two simultaneous appearance events, during which the frequencies of the auroral roar and MF bursts detected at ground level were different from those of the terrestrial hectometric radiation (THR) observed by the Akebono satellite passing over the ground-based stations. This frequency difference confirms that auroral roar and THR are generated at different altitudes across the F peak. We did not observe any simultaneous observations that indicated an identical generation region of auroral roar and THR. In most cases, MF/HF auroral radio emissions were observed only by the ground-based detector, or by the satellite-based detector, even when the satellite was passing directly over the ground-based stations. A higher detection rate was observed from space than from ground level. This can primarily be explained in terms of the idea that the Akebono satellite can detect THR emissions coming from a wider region, and because a considerable portion of auroral radio emissions generated in the bottomside F region are masked by ionospheric absorption and screening in the D/E regions associated with ionization which results from auroral electrons and solar UV radiation.

  10. First results of HF radio science with e-POP RRI and SuperDARN

    Science.gov (United States)

    Perry, G. W.; James, H. G.; Gillies, R. G.; Howarth, A.; Hussey, G. C.; McWilliams, K. A.; White, A.; Yau, A. W.

    2017-01-01

    The first results from coordinated experiments between the Radio Receiver Instrument (RRI) on the Enhanced Polar Outflow Probe (e-POP) and the Super Dual Auroral Radar Network (SuperDARN) Saskatoon high frequency (HF) radar are examined for a conjunction on 8 July 2014. e-POP, a payload on the CAScade, Smallsat and IOnospheric Polar Explorer spacecraft, was located at 380 km altitude, approximately 10° north (geographic) and 2° west of Saskatoon, Canada, moving in a southeast direction. We use a matched filter technique to extract individual received SuperDARN pulses from the RRI data stream. The pulses show characteristics of propagation through the F region ionosphere: they are heavily dispersed, they show significant pulse-to-pulse variability in magnitude, and there is clear evidence that they experienced multipath propagation. We calculate the polarization parameters of the pulses and use them to identify magnetoionic phenomena such as mode-splitting and single-mode fading. These first RRI results provide compelling insight into HF radio wave propagation and show RRI's potential to significantly advance radio science.

  11. An examination of man-made radio noise at 37HF receiving sties

    OpenAIRE

    Vincent, Wilbur R.; Adler, Richard William; Munsch, George F.

    2005-01-01

    Man-made radio noise was examined at 37 HF receiving sites spaced at wide intervals around the world. The measurements were made with the goal of understanding the temporal and spectral structure of each example of man-made noise, determining the sources involved, and developing procedures to minimize the impact of man-made noise on signal reception. All measurements were made at the input terminals of receivers at each site as contrasted to the more traditional field-strength measurement of ...

  12. Amateur Radio Communication Technology Contingency Communication in Emergency Situation

    Directory of Open Access Journals (Sweden)

    Johar Azlee

    2017-01-01

    Full Text Available Disasters cannot be avoided, but efforts can be made to reduce death, injuries and property damages through better communications and better planning to deal with it before it happen. Thus we need to adopt available technology, like the Amateur Radio Communication Technology (ACT, to face this problem. These include providing awareness, training and support for the communities who adopt the technology for Emergency Communication (EC. Through having more qualified Amateur Radio Communities (ARC in the adoption of the ARCT, we would be able to improve the communication before, during and after the disasters struck. There are many challenges and issues in the adoption of the ARCT that would part of this study. This article also describes several case studies of communication failure during Hurricane Katrina (2005 in the USA, as well as disasters in several other countries and Malaysia. The tragedies led to failure of existing communication infrastructure, and were reprieved by the help of the voluntary ARC to support the relief agencies in the evacuation and assistance the disaster victims. Therefore, this article will highlight the significant issues that influence the adoption of ARCT in EC.

  13. Radio Science from an Optical Communications Signal

    Science.gov (United States)

    Moision, Bruce; Asmar, Sami; Oudrhiri, Kamal

    2013-01-01

    NASA is currently developing the capability to deploy deep space optical communications links. This creates the opportunity to utilize the optical link to obtain range, doppler, and signal intensity estimates. These may, in turn, be used to complement or extend the capabilities of current radio science. In this paper we illustrate the achievable precision in estimating range, doppler, and received signal intensity of an non-coherent optical link (the current state-of-the-art for a deep-space link). We provide a joint estimation algorithm with performance close to the bound. We draw comparisons to estimates based on a coherent radio frequency signal, illustrating that large gains in either precision or observation time are possible with an optical link.

  14. Multimode Communication Protocols Enabling Reconfigurable Radios

    Directory of Open Access Journals (Sweden)

    Berlemann Lars

    2005-01-01

    Full Text Available This paper focuses on the realization and application of a generic protocol stack for reconfigurable wireless communication systems. This focus extends the field of software-defined radios which usually concentrates on the physical layer. The generic protocol stack comprises common protocol functionality and behavior which are extended through specific parts of the targeted radio access technology. This paper considers parameterizable modules of basic protocol functions residing in the data link layer of the ISO/OSI model. System-specific functionality of the protocol software is realized through adequate parameterization and composition of the generic modules. The generic protocol stack allows an efficient realization of reconfigurable protocol software and enables a completely reconfigurable wireless communication system. It is a first step from side-by-side realized, preinstalled modes in a terminal towards a dynamic reconfigurable anymode terminal. The presented modules of the generic protocol stack can also be regarded as a toolbox for the accelerated and cost-efficient development of future communication protocols.

  15. Npl Ionospheric Model for Radio Communication and Navigational Applications

    Science.gov (United States)

    Singh Dabas, Raj

    In the areas of Radio Communication and Navigation, present day need of the users are to achieve higher performance communication, better navigation, positioning which can only be possible through improved Ionospheric Modeling, its now casting and forecast-ing. Therefore, National Physical Laboratory (NPL), New Delhi has develop a user friendly, Empirical Ionospheric Model (NPL Model) for the Indian zone which gives all the F-region Parameters like foF2, NmF2, hmF2, Ne Profiles and the Ionospheric Electron Content (IEC) for different Radio Communication/Navigational applications. Basically, two HF prediction models for short and long term predictions are developed for equatorial and low latitude iono-sphere. Short term HF prediction model is based on Multiple Regression Analysis (MRA) for the dependence of F-region parameters namely foF2 and M(3000)F2, on solar 2800 MHz flux (F10), and geomagnetic index Ap whereas for long term prediction, Second Degree (SD) coefficients are generated by fitting monthly median foF2 and M(3000)F2 with corresponding 12 monthly mean sunspot numbers (R12) using data over three solar cycles. For generating MRA coefficients, daily foF2, M(3000)F2 values for each hour, obtained from Delhi (28.6N, 77.1E) digital ionosonde for about half a solar cycle are used. MRA coefficients, separately for quiet (Ap25) periods, for foF2 and M(3000)F2, are obtained for every month over 24 UT times using daily F10 and Ap values. Whereas SD coefficients are obtained each month at all local times for all the 14 stations covering a geographic latitude range from about 0 to 45 N. IEC model is developed in two ways. Firstly, IEC model is also developed using monthly median foF2 and hmF2 values for each hours for all the 14 stations which are feed into IRI 2000 model to calculate respective IEC values for two altitudes namely 1000km and 2000km. Then, second degree coefficients are generated by fitting monthly median IEC with corresponding 12 monthly mean

  16. Software-Defined Radio for Space-to-Space Communications

    Science.gov (United States)

    Fisher, Ken; Jih, Cindy; Moore, Michael S.; Price, Jeremy C.; Abbott, Ben A.; Fritz, Justin A.

    2011-01-01

    A paper describes the Space- to-Space Communications System (SSCS) Software- Defined Radio (SDR) research project to determine the most appropriate method for creating flexible and reconfigurable radios to implement wireless communications channels for space vehicles so that fewer radios are required, and commonality in hardware and software architecture can be leveraged for future missions. The ability to reconfigure the SDR through software enables one radio platform to be reconfigured to interoperate with many different waveforms. This means a reduction in the number of physical radio platforms necessary to support a space mission s communication requirements, thus decreasing the total size, weight, and power needed for a mission.

  17. At the Dawn of Radio Communications

    Directory of Open Access Journals (Sweden)

    V. P. Samokhin

    2017-01-01

    Full Text Available A brief review of the history of radio communications, which were used before the advent of humanity tubes, in the context of the essays in the series "At the root of media", published in the "History of Technical Progress" section of the supplement to our journal "Science and Education". The review covers the main stages of the development of spark radio-telegraph systems, the creation of the first powerful arc and electric machine generators of non-stopping oscillations of the carrier frequency for radiotelephony and the detection features. The first experiments of Mahlon Loomis, scientific and technical achievements of James Maxwell, Henry Hertz, Eduard Branly, Alexander Popov, Oliver Lodge, Jagadish Bosch, Karl Brown, Lee de Forest, Louis Austin, Herman Simon, William Duddel, Valdemar Paulsen, Ernst Alexander, Valentin Vologdin, Semyon Eisenstein and other creators of the nascent radio engineering. Particular attention is paid to the intersections of their work with the work of Thomas Edison, Nikola Tesla, Guglielmo Marconi, Reginald Fessenden and other heroes of our essays.

  18. Rhetorical Perspectives in Radio Communications: The Speaker and the Loudspeaker.

    Science.gov (United States)

    Godfrey, Donald G.

    Radio rhetoric is set apart from traditional rhetoric by the efficacy it commands. This study focuses on rhetorical perspective in radio communication, noting 10 identifiable aspects of radio rhetoric noteworthy in undertaking rhetorical criticism: (1) the pressures of federal regulations which require balanced presentation affect preparation; (2)…

  19. Design and Experimental Investigation for Improving the High Frequency Radio Communication Links between Benghazi-Libya and Sfax-Tunisia.

    Directory of Open Access Journals (Sweden)

    Mohamed Yousef Ahmed Abou-Hussein

    2014-02-01

    Full Text Available In this study, we have experimentally planned to replicate the positive results of the application of ionospheric prediction method to design and improve the high frequency (HF radio communication links between Benghazi-Libya and Sfax-Tunisia. The central radio propagation laboratory (CRPL method of ionospheric prediction of the National Bureau of Standards (NBS in U.S.A was used in the calculations of the optimal working frequencies for reliable HF radio communication links between Benghazi-Libya and Sfax-Tunisia. The results were drawn in the form of curves by using the computer. The computer was used to measure the received signal level variation of a frequency 17.500 Megahertz (MHz, which was transmitted with a power of 100 Kilowatt (KW from the Tunis Republic Broadcasting station in SFAX city, directed to the east region. The measurements were taken during daytime's for winter (December, January& February and summer (June, July & August seasons.

  20. Experimental radio frequency link for Ka-band communications applications

    Science.gov (United States)

    Fujikawa, Gene; Conray, Martin J.; Saunders, Alan L.; Pope, Dale E.

    1988-01-01

    An experimental radio frequency link has been demonstrated to provide two-way communication between a remote user ground terminal and a ground-based Ka-band transponder. Bit-error-rate performance and radio frequency characteristics of the communication link were investigated.

  1. Phenomena in the ionosphere-magnetosphere system induced by injection of powerful HF radio waves into nightside auroral ionosphere

    Directory of Open Access Journals (Sweden)

    N. F. Blagoveshchenskaya

    2005-01-01

    Full Text Available Experimental results from three ionospheric HF pumping experiments in overdense E or F regions are summarized. The experiments were conducted by the use of the EISCAT HF Heating facility located near Tromsø, Norway, allowing HF pumping the ionosphere in a near geomagnetic field-aligned direction. Distinctive features related to auroral activations in the course of the experiments are identified. Typical features observed in all experiments are the following: generation of scattered components in dynamic HF radio scatter Doppler spectra; strong increase of ion temperatures Ti and local ionospheric electric field E0; modification of the auroral arc and local spiral-like formation. However, some effects were observed only when the HF pump wave was reflected from the F2 layer. Among them are the generation of intense field-aligned ion outflows, and a strong increase in the electron temperature Te with altitude. A possible scenario for the substorm triggering due to HF pumping into an auroral ionosphere is discussed. The authors present their interpretation of the data as follows. It is suggested that two populations of charged particles are at play. One of them is the runaway population of electrons and ions from the ionosphere caused by the effects of the powerful HF radio wave. The other is the population of electrons that precipitate from the magnetosphere. It is shown that the hydrodynamical equilibrium was disrupted due to the effects of the HF pumping. We estimate that the parallel electric field can reach values of the order of 30mV/m during substorm triggering.

  2. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  3. Science on air: the role of radio in science communication

    Directory of Open Access Journals (Sweden)

    Merzagora Matteo

    2004-12-01

    Full Text Available The international symposium “Science on air: the role of radio in science communication” was held inTrieste on 1 and 2 October, 2004. To our knowledge, it is the first conference ever specifically held on science on radio, and it is certainly the first time science radio journalists, researchers, and mediaexperts from 16 different countries met to discuss their journalistic practice and the role of radio in science communication.The main results are presented in this article.

  4. HF Propagation Directions Observed by the e-POP Radio Receiver Instrument

    Science.gov (United States)

    James, H. G.; Perry, G. W.

    2016-12-01

    We have investigated high-frequency (HF) propagation direction measurements by the e-POP Radio Receiver Instrument (RRI) on the CASSIOPE spacecraft. The measurement of the direction of arrival (DOA) of electromagnetic waves propagating in the ionosphere is a desirable technique for the analysis of both spontaneous emissions and waves emitted by ground transmitters. In the case of detection of waves launched by HF radars, DOA evidence at low earth orbit close to regions of (coherent) backscatter may help to understand the details of the physics of scatter of radar waves, by the examination of waves both incident on and scattered by irregularities of density. The RRI has been used to observe direct transmissions from the ground for evaluation of a DOA detection algorithm. Signals are detected with two orthogonal 6-m distributed dipoles on RRI working at frequencies up to about 18 MHz. When ground sources emit electric-field polarisation of one of the Ordinary (O) and Extraordinary (X) cold-plasma modes, the DOA of transmissions propagating near the bore sight of the RRI crossed dipoles can be determined. In the instance of transversely polarized transmissions from a SuperDARN source, the emissions are the sum of the two cold-plasma modes and we depend on differential refraction to temporally resolve the pulsed transmissions into two modes for DOA measurement by the RRI. DOA information can help to confirm the existence of horizontal density gradients that can bend rays away from the great-circle beam paths traditionally assumed in the SuperDARN fields of view.

  5. Radio Gaga? Intra-team communication of Australian Rules Football umpires - effect of radio communication on content, structure and frequency.

    Science.gov (United States)

    Neville, Timothy J; Salmon, Paul M; Read, Gemma J M

    2017-07-31

    Intra-team communication plays an important role in team effectiveness in various domains including sport. As such, it is a key consideration when introducing new tools within systems that utilise teams. The difference in intra-team communication of Australian Rules Football (AFL) umpiring teams was studied when umpiring with or without radio communications technology. A cross-sectional observational study was conducted to analyse the verbal communication of seven umpiring teams (20 participants) grouped according to their experience with radio communication. The results identified that radio communication technology increased the frequency and altered the structure of intra-team communication. Examination of the content of the intra-team communication identified impacts on the 'Big Five' teamwork behaviours and associated coordinating mechanisms. Analysis revealed that the communications utilised did not align with the closed-loop form of communication described in the Big Five model. Implications for teamwork models, coaching and training of AFL umpires are discussed. Practitioner Summary: Assessing the impact of technology on performance is of interest to ergonomics practitioners. The impact of radio communications on teamwork is explored in the highly dynamic domain of AFL umpiring. When given radio technology, intra-team communication increased which supported teamwork behaviours, such as backup behaviour and mutual performance monitoring.

  6. Radio for formal education and for development communication.

    Science.gov (United States)

    Jamison, D T

    1978-09-01

    A substantial body of literature documents the successful use of open radio broadcasting, radio campaigns, and radio-listening groups in nonformal education and other aspects of development communication. The 4 alternative strategies for using radio in formal education -- using radio to enrich learning, direct instruction, extending in-school education, and distance learning -- need to be assessed in terms of users' needs. The use of radio to enrich in-school education holds little promise for major improvements, but the potential for the use of radio in direct instruction in 1 or more subjects is promising and presents a strong challenge to educators. Case studies of 2 Mexican projects to extend school in order to expand the rural population's access to information and schools were disappointing. Both projects showed that radio could teach about as effectively as traditional elementary school teachers, but neither expanded beyond the pilot stage. Better financing and a firmer government commitment might have made a difference. The use of radio in formal education as a component of a distance-learning system has been successful in Kenya and the Dominican Republic, among other places. The best use of open broadcast is to transmit an interesting message; the most appropriate use of listening-group strategies -- radio schools, farm forums, and radio animation -- are to promote more complex and longterm changes. Communication planners need to be aware that radio can be used in numerous ways in response to a variety of goals. 4 projects are reviewed to illustrate instances in which radio has realized its goals with special success -- the Kenyan health broadcasts, the radio program that used nutrition "ads," the Guatemalan agricultural information programs, and the Tanzania radio campaigns. These projects show that the development goals being promoted and the special characteristics of the project determine the strategy, its effects, and its transferability.

  7. e-POP Radio Science Using Amateur Radio Transmissions

    Science.gov (United States)

    Frissell, N. A.; Perry, G. W.; Miller, E. S.; Shovkoplyas, A.; Moses, M. L.; James, H. G.; Yau, A. W.

    2015-12-01

    A major component of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) mission is to utilize artificially generated radio emissions to study High Frequency (HF) radio wave propagation in the ionosphere. In the North American and European sectors, communications between amateur radio operators are a persistent and abundant source source of HF transmissions. We present the results of HF radio wave propagation experiments using amateur radio transmissions as an HF source for e-POP RRI. We detail how a distributed and autonomously operated amateur radio network can be leveraged to study HF radio wave propagation as well as the structuring and dynamics of the ionosphere over a large geographic region. In one case, the sudden disappearance of nearly two-dozen amateur radio HF sources located in the midwestern United States was used to detect a enhancement in foF2 in that same region. We compare our results to those from other more conventional radio instruments and models of the ionosphere to demonstrate the scientific merit of incorporating amateur radio networks for radio science at HF.

  8. HF Detecting Radar and Communication Frequency Selection System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Real time communication (RTC) frequency selecting system is used to the maximum usable frequency (MUF) between two communication points, then finds the best frequency between 0. 85 MUF and 1.0MUF. Determination of electric wave delay is mostly introduced, and of MUF values, the form of frequencycontrolling code and relative interface circuits in the frequency selecting system are introduced in detail.

  9. Inflatable Reflector For Solar Power And Radio Communication

    Science.gov (United States)

    Sercel, Joel; Gilchriest, Carl; Ewell, Rich; Herman, Martin; Rascoe, Daniel L.; Nesmith, Bill J.

    1995-01-01

    Report proposes installation of lightweight inflatable reflector structure aboard spacecraft required to both derive power from sunlight and communicate with Earth by radio when apparent position of Earth is at manageably small angle from line of sight to Sun. Structure contains large-aperture paraboloidal reflector aimed toward Sun and concentrates sunlight onto photovoltaic power converter and acts as main reflector of spacecraft radio-communication system.

  10. Performance evaluation of cognitive radio in advanced metering infrastructure communication

    Science.gov (United States)

    Hiew, Yik-Kuan; Mohd Aripin, Norazizah; Din, Norashidah Md

    2016-03-01

    Smart grid is an intelligent electricity grid system. A reliable two-way communication system is required to transmit both critical and non-critical smart grid data. However, it is difficult to locate a huge chunk of dedicated spectrum for smart grid communications. Hence, cognitive radio based communication is applied. Cognitive radio allows smart grid users to access licensed spectrums opportunistically with the constraint of not causing harmful interference to licensed users. In this paper, a cognitive radio based smart grid communication framework is proposed. Smart grid framework consists of Home Area Network (HAN) and Advanced Metering Infrastructure (AMI), while AMI is made up of Neighborhood Area Network (NAN) and Wide Area Network (WAN). In this paper, the authors only report the findings for AMI communication. AMI is smart grid domain that comprises smart meters, data aggregator unit, and billing center. Meter data are collected by smart meters and transmitted to data aggregator unit by using cognitive 802.11 technique; data aggregator unit then relays the data to billing center using cognitive WiMAX and TV white space. The performance of cognitive radio in AMI communication is investigated using Network Simulator 2. Simulation results show that cognitive radio improves the latency and throughput performances of AMI. Besides, cognitive radio also improves spectrum utilization efficiency of WiMAX band from 5.92% to 9.24% and duty cycle of TV band from 6.6% to 10.77%.

  11. 49 CFR 220.43 - Radio communications consistent with federal regulations and railroad operating rules.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Radio communications consistent with federal... Radio and Wireless Communication Procedures § 220.43 Radio communications consistent with federal regulations and railroad operating rules. Radio communication shall not be used in connection with a...

  12. 49 CFR 220.37 - Testing radio and wireless communication equipment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Testing radio and wireless communication equipment... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.37 Testing radio and wireless communication equipment. (a) Each radio, and...

  13. Integrated Train Ground Radio Communication System Based TD-LTE

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hongli; CAO Yuan; ZHU Li; XU Wei

    2016-01-01

    In existing metro systems, the train ground radio communication system for different applications are deployed independently. Investing and constructing the communication infrastructures repeatedly wastes substan-tial social resources, and it brings difficulties to maintain all these infrastructures. We present the communication Quality of service (QoS) requirement for different train ground radio applications. An integrated TD-LTE based train ground radio communication system for the metro system (LTE-M) is designed next. In order to test the LTE-M system performance, an indoor testing environment is set up. The channel simulator and programmable attenua-tors are used to simulate the real metro environment. Ex-tensive test results show that the designed LTE-M system performance satisfies metro communication requirements.

  14. Radio communication for Communications-Based Train Control (CBTC): A tutorial and survey

    DEFF Research Database (Denmark)

    Farooq, Jahanzeb; Soler, José

    2017-01-01

    industry. We believe that this paper fills the much-needed gap. It aims to present a comprehensive tutorial, as well as a survey of the stateof- the-art, of CBTC and the role of radio communication in it. The operation and fundamental components of a CBTC system are discussed. A summary of the evolution...... of the communication technologies used for modern railway signalling is presented. The benefits and drawbacks of using a radio communication technology, particularly Wi-Fi, and the challenges it introduces, are discussed. Best practices in the design of a CBTC radio network and the measures to optimize its......Over the last decade, railway industry has seen a huge transition from conventional railway signalling systems to modern, communication-based signalling systems. Communications-Based Train Control (CBTC) is a modern communication-based system that uses radio communication to transfer timely...

  15. Bidirectional communication in an HF hybrid organic/solution-processed metal-oxide RFID tag

    NARCIS (Netherlands)

    Myny, K.; Rockelé, M.; Chasin, A.; Pham, D.V.; Steiger, J.; Botnaras, S.; Weber, D.; Herold, B.; Ficker, J.; Van Putten, B.D.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2014-01-01

    A bidirectional communication protocol allows radio-frequency identification (RFID) tags to have readout of multiple tags in the RF field without collision of data. In this paper, we realized bidirectional communication between a reader system and thin-film RFID tag by introducing a novel protocol f

  16. Bidirectional communication in an HF hybrid organic/solution-processed metal-oxide RFID tag

    NARCIS (Netherlands)

    Myny, K.; Rockelé, M.; Chasin, A.; Pham, D.V.; Steiger, J.; Botnaras, S.; Weber, D.; Herold, B.; Ficker, J.; Van Putten, B.D.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2014-01-01

    A bidirectional communication protocol allows radio-frequency identification (RFID) tags to have readout of multiple tags in the RF field without collision of data. In this paper, we realized bidirectional communication between a reader system and thin-film RFID tag by introducing a novel protocol

  17. Bidirectional communication in an HF hybrid organic/solution-processed metal-oxide RFID tag

    NARCIS (Netherlands)

    Myny, K.; Rockelé, M.; Chasin, A.; Pham, D.V.; Steiger, J.; Botnaras, S.; Weber, D.; Herold, B.; Ficker, J.; Van Putten, B.D.; Gelinck, G.H.; Genoe, J.; Dehaene, W.; Heremans, P.

    2014-01-01

    A bidirectional communication protocol allows radio-frequency identification (RFID) tags to have readout of multiple tags in the RF field without collision of data. In this paper, we realized bidirectional communication between a reader system and thin-film RFID tag by introducing a novel protocol f

  18. Physical Layer Definition for a Long-Haul HF Antarctica to Spain Radio Link

    Directory of Open Access Journals (Sweden)

    Rosa Ma Alsina-Pagès

    2016-05-01

    Full Text Available La Salle and the Observatori de l’Ebre (OE have been involved in a remote sensing project in Antarctica for the last 11 years. The OE has been monitoring the geomagnetic activity for more than twenty years and also the ionospheric activity of the last ten years in the Spanish Antarctic Station Juan Carlos I (ASJI (62.7 ° S, 299.6 ° E. La Salle is finishing the design and testing of a low-power communication system between the ASJI and Cambrils (41.0 ° N, 1.0 ° E with a double goal: (i the transmission of data from the sensors located at the ASJI and (ii the performance of an oblique ionospheric sounding of a 12,760 km HF link. Previously, La Salle has already performed sounding and modulation tests to describe the channel performance in terms of availability, Signal-to-Noise Ratio (SNR, Doppler spread and delay spread. This paper closes the design of the physical layer, by means of the channel error study and the synchronization performance, and concludes with a new physical layer proposal for the Oblique Ionosphere Sounder. Narrowband and wideband frames have been defined to be used when the oblique sounder performs as an ionospheric sensor. Finally, two transmission modes have been defined for the modem performance: the High Robustness Mode (HRM for low SNR hours and the High Throughput Mode (HTM for the high SNR hours.

  19. Electrical properties of radio-frequency sputtered HfO{sub 2} thin films for advanced CMOS technology

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Pranab Kumar; Roy, Asim, E-mail: 28.asim@gmail.com [Department of Physics, National Institute of Technology Silchar, Silchar-788010, Assam, India Phone: +91-3842-224879 (India)

    2015-08-28

    The Hafnium oxide (HfO{sub 2}) high-k thin films have been deposited by radio frequency (rf) sputtering technique on p-type Si (100) substrate. The thickness, composition and phases of films in relation to annealing temperatures have been investigated by using cross sectional FE-SEM (Field Emission Scanning Electron Microscope) and grazing incidence x-ray diffraction (GI-XRD), respectively. GI-XRD analysis revealed that at annealing temperatures of 350°C, films phases change to crystalline from amorphous. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the annealed HfO{sub 2} film have been studied employing Al/HfO{sub 2}/p-Si metal–oxide–semiconductor (MOS) structures. The electrical properties such as dielectric constant, interface trap density and leakage current density have been also extracted from C-V and I-V Measurements. The value of dielectric constant, interface trap density and leakage current density of annealed HfO{sub 2} film is obtained as 23,7.57×1011eV{sup −1} cm{sup −2} and 2.7×10{sup −5} Acm{sup −2}, respectively. In this work we also reported the influence of post deposition annealing onto the trapping properties of hafnium oxide and optimized conditions under which no charge trapping is observed into the dielectric stack.

  20. Towards Ultrahigh Speed Impulse Radio THz Wireless Communications

    DEFF Research Database (Denmark)

    Yu, Xianbin; Galili, Michael; Morioka, Toshio

    2015-01-01

    THz impulse radio technologies promise a new paradigm of fast wireless access with simplified wireless reception. However, huge loss of propagating broad bandwidth THz impulse radio signals limits THz wireless transmission distance and reduces the achievable link data rates. In this paper, we...... evaluate the realistic throughput and accessible wireless range of a THz impulse radio communication link based on a uni-travelling photodiode (UTC-PD) as THz emitter and a photoconductive antenna (PCA) as THz receiver. The impact of highly frequency-selective THz channel and the noise in the system...

  1. Excitation of small-scale waves in the F region of the ionosphere by powerful HF radio waves

    Science.gov (United States)

    Blagoveshchenskaya, N. F.; Chernyshev, M. Y.; Kornienko, V. A.

    1998-01-01

    Ionospheric small-scale waves in the F region, initiated by heating facilities in Nizhniy Novgorod, have been studied by the method of field-aligned scattering of diagnostic HF radio signals. Experimental data have been obtained on the radio path Kiev-N. Novgorod-St. Petersburg during heating campaigns with heater radiated power ERP = 20 MW and 100 MW. Observations of scattered HF signals have been made by a Doppler spectrum device with high temporal resolution. Analysis of the experimental data shows a relation between the heater power level and the parameters of ionospheric small-scale oscillations falling within the range of Pc 3-4 magnetic pulsations. It is found that the periods of wave processes in the F region of the ionosphere, induced by the heating facility, decrease with increasing heating power. The level of heating power also has an impact on the horizontal east-west component of the electric field E, the vertical component of the Doppler velocity Vd and the amplitude of the vertical displacements M of the heated region. Typical magnitudes of these parameters are the following: E = 1.25 mVm, Vd = 6 ms, M = 600-1500 m for ERP = 20 MW and E = 2.5-4.5 mVm, Vd = 11-25 ms, M = 1000-5000 m for ERP = 100 MW. The results obtained confirm the hypothesis of excitation of the Alfvén resonator by powerful HF radio waves which leads to the generation of magnetic field oscillations in the heated region giving rise to artificial Pc 3-4 magnetic pulsations and ionospheric small-scale wave processes. In this situation an increase of the heater power would lead to a growth of the electric field of hydromagnetic waves propagating in the ionosphere as well as the amplitude of the vertical displacements of the heated region.

  2. Communicating radio astronomy with the public: Another point of view

    Science.gov (United States)

    Varano, S.

    2008-06-01

    Radio waves cannot be sensed directly, but they are used in daily life by almost everybody. Even so, the majority of the general public do not even know that celestial bodies emit radio waves. Presenting invisible radiation to a general audience with little or no background knowledge in physics is a difficult task. In addition, much important technology now commonplace in many other scientific fields was pioneered by radio observatories in their efforts to detect and process radio signals from the Universe. Radio astronomy outreach does not have such a well-established background as optical astronomy outreach. In order to make radio astronomy accessible to the public, it is necessary either to add more scientific detail or to find a different way of communicating. In this paper we present examples from our work at the Visitor Centre "Marcello Ceccarelli", which is part of the Medicina Radio Observatory, operated by the Institute of Radio Astronomy (IRA) in Bologna, which in turn is part of the National Institute for Astrophysics (INAF).

  3. Voice Communications Over Packet Radio Networks.

    Science.gov (United States)

    1985-03-01

    standpoint, the major difference between telephone networks and packet radio networks concerns the availabilty of time slots over each frame. The...mentioning that simulations require large amounts of detailed knowledge about the structure of the system and about patterns of usage . Simulation is...proposed time slot algorithm adopts. Moreover, the proposed time slot scheme may give more uniform usage of time slots in each time frame. In addition

  4. 75 FR 20951 - Amendment of the Commission's Rules Regarding Amateur Radio Service Communications During...

    Science.gov (United States)

    2010-04-22

    ... COMMISSION 47 CFR Part 97 Amendment of the Commission's Rules Regarding Amateur Radio Service Communications...-based communications for emergency responders, experience has shown that amateur radio has played an... radio communication at its disposal to provide essential communication needs in connection with...

  5. 49 CFR 220.21 - Railroad operating rules; radio communications; recordkeeping.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Railroad operating rules; radio communications...) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.21 Railroad operating rules; radio communications; recordkeeping. (a)...

  6. Technology Evaluation of Programmable Communicating Thermostats with Radio Broadcast Data System Communications

    Energy Technology Data Exchange (ETDEWEB)

    Herter, Karen; Wayland, Seth

    2008-10-31

    Programmable Communicating Thermostats are thermostats that can be programmed by the user to respond to signals indicating a grid-level system emergency or pricing event. The California Energy Commission is considering standards that would include a requirement for Programmable Communicating Thermostats in residential and small commercial applications. The current specification for Programmable Communicating Thermostats requires Radio Data System communications to Programmable Communicating Thermostats. This study tested the signal strength and reliability of Radio Data System signals at 40 customer sites within the Sacramento Municipal Utility District, which is serviced by 17 radio stations that already transmit Radio Data System signals. The study also tested the functionality of a commercially available Programmable Communicating Thermostat for compliance with California Energy Commission design standards. Test results demonstrated that Radio Data System is capable of reliably sending price and emergency signals. This study also provides evidence that existing Programmable Communicating Thermostats, on receiving a Radio Data System pricing or event signal, are capable of automatically increasing set points to a customer-determined or utility-determined level, thus providing air-conditioning demand response within seconds or just a few (less than 5) minutes.

  7. A cellular-based solution for radio communications in MOUT

    NARCIS (Netherlands)

    Overduin, R.

    2005-01-01

    A short-term and potentially cost-effective solution is proposed for tactical radio communications in Military Operations in Urban Terrain (MOUT) for the Royal Netherlands Army (RNLA). Measurements and computer simulations presented show that on average, outdoor ranges in MOUT as attainable with

  8. Rainfall measurement using radio links from cellular communication networks

    NARCIS (Netherlands)

    Leijnse, H.; Uijlenhoet, R.; Stricker, J.N.M.

    2007-01-01

    We investigate the potential of radio links such as employed by commercial cellular communication companies to monitor path-averaged rainfall. We present an analysis of data collected using two 38-GHz links during eight rainfall events over a 2-month period (October¿November 2003) during mostly stra

  9. A cellular-based solution for radio communications in MOUT

    NARCIS (Netherlands)

    Overduin, R.

    2005-01-01

    A short-term and potentially cost-effective solution is proposed for tactical radio communications in Military Operations in Urban Terrain (MOUT) for the Royal Netherlands Army (RNLA). Measurements and computer simulations presented show that on average, outdoor ranges in MOUT as attainable with RNL

  10. Extended x-ray absorption fine structure measurements on radio frequency magnetron sputtered HfO2 thin films deposited with different oxygen partial pressures.

    Science.gov (United States)

    Maidul Haque, S; Nayak, C; Bhattacharyya, Dibyendu; Jha, S N; Sahoo, N K

    2016-03-20

    Two sets of HfO2 thin film have been deposited by the radio frequency magnetron sputtering technique at various oxygen partial pressures, one set without any substrate bias and another set with a 50 W pulsed dc substrate bias. The films have been characterized by extended x-ray absorption fine structure (EXAFS) measurements at the Hf L3 edge, and the structural information obtained from analysis of the EXAFS data has been used to explain the macroscopic behavior of the refractive index obtained from spectroscopic ellipsometry measurements. It has been observed that the variation of refractive index with oxygen partial pressure depends on the Hf-Hf bond length for the set of films deposited without substrate bias, while for the other set of films deposited with pulsed dc substrate bias, it depends on the oxygen coordination of the nearest neighbor shell surrounding Hf sites.

  11. MicrobeWorld Radio and Communications Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Barbara Hyde

    2006-11-22

    MicrobeWorld is a 90-second feature broadcast daily on more than 90 public radio stations and available from several sources as a podcast, including www.microbeworld.org. The feature has a strong focus on the use and adapatbility of microbes as alternative sources of energy, in bioremediation, their role in climate, and especially the many benefits and scientific advances that have resulting from decoding microbial genomes. These audio features are permanantly archived on an educational outreach site, microbeworld.org, where they are linked to the National Science Education Standards. They are also being used by instructors at all levels to introduce students to the multiple roles and potential of microbes, including a pilot curriculum program for middle-school students in New York.

  12. Speech Communication Via Radio and Television.

    Science.gov (United States)

    Starlin, Glenn; Sherriffs, Ronald

    Designed to serve as a practical introduction to the functions of the broadcast media and as a guide to adjustment to demands imposed by the media on speakers, this book attempts to deal with special problems of the ordinary citizen in preparation for broadcast talks. A first part focuses on the media--changing patterns of communication,…

  13. Integrated Radio and Optical Communication (iROC)

    Science.gov (United States)

    Raible, Daniel; Romanofsky, Robert; Pease, Gary; Kacpura, Thomas

    2016-01-01

    This is an overview of the Integrated Radio and Optical Communication (iROC) Project for Space Communication and Navigation Industry Days. The Goal is to develop and demonstrate new, high payoff space technologies that will promote mission utilization of optical communications, thereby expanding the capabilities of NASA's exploration, science, and discovery missions. This is an overview that combines the paramount features of select deep space RF and optical communications elements into an integrated system, scalable from deep space to near earth. It will realize Ka-band RF and 1550 nanometer optical capability. The approach is to prototype and demonstrate performance of key components to increase to TRL-5, leading to integrated hybrid communications system demonstration to increase to TRL-5, leading to integrated hybrid communications system demonstration.

  14. Electromagnetic compatibility fundamentals applied to spacecraft radio communication systems

    Science.gov (United States)

    Haber, F.; Celebiler, M.; Weil-Malherbe, C.

    1971-01-01

    A design guide for minimizing electromagnetic interference in aerospace communication equipment for ground stations is presented. Specifically treated are the mechanisms of generating unwanted radio emissions that may affect station operations as well as other communications services, the mechanisms by which sensitive receivers become susceptible to interference, means for reducing interference, standard methods of measurement, and the problems of site selection. The sources of interference are viewed primarily as originating from communications transmitters aboard spacecraft and aircraft, ground transmitters within and outside the ground stations, and other electrical sources on the ground that are not intended to radiate.

  15. Radio propagation for space communications systems

    Science.gov (United States)

    Ippolito, L. J.

    1981-01-01

    This paper presents a review of the most recent information on the effects of the earth's atmosphere on space communications systems. Models and techniques used in the prediction of atmospheric effects as influenced by frequency, geography, elevation angle, and type of transmission are discussed. Recent data on performance characteristics obtained from direct measurements on satellite links operating to above 30 GHz are reviewed. Particular emphasis is placed on the effects of precipitation on the earth-space path, including rain attenuation, and rain and ice-particle depolarization. Sky noise, antenna gain degradation, scintillations, and bandwidth coherence are also discussed. The impact of the various propagation factors on communications system design criteria is presented. These criteria include link reliability, power margins, noise contributions, modulation and polarization factors, channel crosstalk, error-rate, and bandwidth limitations.

  16. 77 FR 28797 - Redundancy of Communications Systems: Backup Power Private Land Mobile Radio Services: Selection...

    Science.gov (United States)

    2012-05-16

    ..., Communications common carriers, Communications equipment, Radio, Telecommunications, Telephone, Television... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 12 and 90 Redundancy of Communications Systems: Backup Power Private Land...

  17. Currents, HF Radio-derived, Monterey Bay, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  18. Currents, HF Radio-derived, SF Bay, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  19. Currents, HF Radio-derived, Monterey Bay, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  20. Currents, HF Radio-derived, Ano Nuevo, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  1. Currents, HF Radio-derived, SF Bay Outlet, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  2. Currents, HF Radio-derived, SF Bay Outlet, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  3. Currents, HF Radio-derived, SF Bay Outlet, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  4. Currents, HF Radio-derived, SF Bay, 33 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 33 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  5. Currents, HF Radio-derived, Bodega Bay, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  6. Currents, HF Radio-derived, Bodega Bay, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  7. Currents, HF Radio-derived, Bodega Bay, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  8. Currents, HF Radio-derived, Ano Nuevo, 1 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  9. Currents, HF Radio-derived, Ano Nuevo, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  10. Currents, HF Radio-derived, Ano Nuevo, 1 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 1 hour average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN EXPERIMENTAL...

  11. Currents, HF Radio-derived, Ano Nuevo, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  12. Currents, HF Radio-derived, Ano Nuevo, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  13. Currents, HF Radio-derived, SF Bay Outlet, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  14. Currents, HF Radio-derived, Monterey Bay, Normal Model, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal model....

  15. Currents, HF Radio-derived, Monterey Bay, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  16. Currents, HF Radio-derived, SF Bay Outlet, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  17. Currents, HF Radio-derived, Bodega Bay, 25 hr, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  18. Currents, HF Radio-derived, Monterey Bay, 25 hr, Zonal, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the 25 hour running average of the zonal component of ocean surface currents derived from High Frequency Radio-derived measurements. THIS IS AN...

  19. Currents, HF Radio-derived, SF Bay Outlet, Normal Model, Meridional, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data is the meridional component of ocean surface currents derived from High Frequency Radio-derived measurements, with missing values filled in by a normal...

  20. An Optical Receiver Post-Processing System for the Integrated Radio and Optical Communications Software Defined Radio Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Tokars, Roger P.; Wroblewski, Adam C.

    2016-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration's (NASA) Glenn Research Center is investigating the feasibility of a hybrid radio frequency (RF) and optical communication system for future deep space missions. As a part of this investigation, a test bed for a radio frequency (RF) and optical software defined radio (SDR) has been built. Receivers and modems for the NASA deep space optical waveform are not commercially available so a custom ground optical receiver system has been built. This paper documents the ground optical receiver, which is used in order to test the RF and optical SDR in a free space optical communications link.

  1. Mitigating Doppler shift effect in HF multitone data modem

    Science.gov (United States)

    Sonlu, Yasar

    1989-09-01

    Digital communications over High Frequency (HF) radio channels are getting important in recent years. Current HF requirements are for data transmission at rates 2.4 kbps or more to accommodate computer data links and digital secure voice. HF modems which were produced to meet these speeds are, serial modems and parallel modems. On the other hand, the HF sky-wave communication medium, the ionosphere, has some propagation problems such as multipath and Doppler shift. The effect of Doppler shift in a parallel modem which employs Differential Quadrature Phase Shift Keying (DQPSK) modulation is considered and a correction method to mitigate the Doppler Shift effect is introduced.

  2. SOCIOLINGUISTIC ASPECTS OF THE STUDY OF PECULIARITIES OF RADIO COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Nataliya Pazyura

    2016-06-01

    Full Text Available Purpose. Flight safety has always been in the center of attention of scientists and practitioners in aviation. That is why in the end of the last century the ICAO assembly recognized inadequate English proficiency among flight crews and controllers as a contributing factor in aviation accidents. It also directed the ICAO’s Air Navigation Commission (ANC to strengthen the provisions for the use of English in aeronautical radiotelephony (air traffic communications in Annex 1 - Personnel Licensing and Annex 10 – Aeronautical Telecommunications. Results. The article is devoted to the study of peculiarities of communication in aviation – radio communication between an air traffic controller and pilot, which is very important for promotion of flight safety. The author pays special attention to the study of social factors influencing the choice of certain lexical units and functional styles. Methods. For our research we used scientific general methods which are main ways of studying scientific sources, and comparative-historical method for synchronic comparison of event in the same region. Discussion. The factors that explain such linguistic choice during communication have been characterized. Similar and different features of professional radio communication and usual every day communication have been revealed. Some examples are given and explained according to specific professional activity.

  3. Software Defined Radio Architecture Contributions to Next Generation Space Communications

    Science.gov (United States)

    Kacpura, Thomas J.; Eddy, Wesley M.; Smith, Carl R.; Liebetreu, John

    2015-01-01

    systems, as well as those communications and navigation systems operated by international space agencies and civilian and government agencies. In this paper, we review the philosophies, technologies, architectural attributes, mission services, and communications capabilities that form the structure of candidate next-generation integrated communication architectures for space communications and navigation. A key area that this paper explores is from the development and operation of the software defined radio for the NASA Space Communications and Navigation (SCaN) Testbed currently on the International Space Station (ISS). Evaluating the lessons learned from development and operation feed back into the communications architecture. Leveraging the reconfigurability provides a change in the way that operations are done and must be considered. Quantifying the impact on the NASA Space Telecommunications Radio System (STRS) software defined radio architecture provides feedback to keep the standard useful and up to date. NASA is not the only customer of these radios. Software defined radios are developed for other applications, and taking advantage of these developments promotes an architecture that is cost effective and sustainable. Developments in the following areas such as an updated operating environment, higher data rates, networking and security can be leveraged. The ability to sustain an architecture that uses radios for multiple markets can lower costs and keep new technology infused.

  4. Modeling radio communication blackout and blackout mitigation in hypersonic vehicles

    CERN Document Server

    Kundrapu, Madhusudhan; Beckwith, Kristian; Stoltz, Peter; Shashurin, Alexey; Keidar, Michael

    2014-01-01

    A procedure for the modeling and analysis of radio communication blackout of hypersonic vehicles is presented. A weakly ionized plasma generated around the surface of a hypersonic reentry vehicle traveling at Mach 23 was simulated using full Navier-Stokes equations in multi-species single fluid form. A seven species air chemistry model is used to compute the individual species densities in air including ionization - plasma densities are compared with experiment. The electromagnetic wave's interaction with the plasma layer is modeled using multi-fluid equations for fluid transport and full Maxwell's equations for the electromagnetic fields. The multi-fluid solver is verified for a whistler wave propagating through a slab. First principles radio communication blackout over a hypersonic vehicle is demonstrated along with a simple blackout mitigation scheme using a magnetic window.

  5. The effect of plasma density structure on HF radio wave propagation at auroral and polar latitudes measured by e-POP

    Science.gov (United States)

    Perry, G. W.; James, H. G.; Gillies, R.; McWilliams, K. A.; St-Maurice, J. P.; Yau, A. W.

    2015-12-01

    One of the scientific objectives of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) is to study ionospheric density structure and its impact on High Frequency (HF) radio wave propagation. We present a survey of several ePOP RRI transits through isolated beams of the Super Dual Auroral Radar Network (SuperDARN) Saskatoon and Rankin Inlet radars. It reveals that the spreading of a SuperDARN beam beyond its nominal azimuthal beam width of 3.24° is a common occurrence at auroral and polar latitudes. Furthermore, on multiple occasions, lateral deviations of a beam's power peak by several beam widths was measured, indicating the presence of significant plasma density gradients along the ray path. The e-POP RRI measurements illustrate that our understanding and recognition of plasma density gradients and their influence on HF radio wave propagation is limited. We report on the results of employing HF ray tracing techniques to quantify the impact of ionospheric structuring on HF radio wave propagation, and consider the source of the gradients contributing to the spreading of the SuperDARN beams.

  6. Tunnel radio communications system at Stanford Linear Accelerator Center

    Energy Technology Data Exchange (ETDEWEB)

    Struven, W.C.

    1980-07-01

    A unique single frequency, dual daisy chain tunnel radio communication system has been developed for use in our new Positron-Electron Storage Ring. Communications are possible between portables in the underground ring and between a portable in the ring and all control rooms on the site. The system is designed as a wide band facility and therefore can carry many simplex and duplex transmissions. This system utilizes TV twinlead as a distributed antenna and repeater amplifiers to cover more than 7000 feet of underground tunnel. The design philosophy, tests and initial design are discussed and contrasted with the final implementation of the system. Future uses of the system are discussed.

  7. Implantable radio frequency identification sensors: wireless power and communication.

    Science.gov (United States)

    Hutchens, Chriswell; Rennaker, Robert L; Venkataraman, Srinivasan; Ahmed, Rehan; Liao, Ran; Ibrahim, Tamer

    2011-01-01

    There are significant technical challenges in the development of a fully implantable wirelessly powered neural interface. Challenges include wireless transmission of sufficient power to the implanted device to ensure reliable operation for decades without replacement, minimizing tissue heating, and adequate reliable communications bandwidth. Overcoming these challenges is essential for the development of implantable closed loop system for the treatment of disorders ranging from epilepsy, incontinence, stroke and spinal cord injury. We discuss the development of the wireless power, communication and control for a Radio-Frequency Identification Sensor (RFIDS) system with targeted power range for a 700 mV, 30 to 40 uA load attained at -2 dBm.

  8. Networked Operations of Hybrid Radio Optical Communications Satellites

    Science.gov (United States)

    Hylton, Alan; Raible, Daniel

    2014-01-01

    In order to address the increasing communications needs of modern equipment in space, and to address the increasing number of objects in space, NASA is demonstrating the potential capability of optical communications for both deep space and near-Earth applications. The Integrated Radio Optical Communications (iROC) is a hybrid communications system that capitalizes on the best of both the optical and RF domains while using each technology to compensate for the other's shortcomings. Specifically, the data rates of the optical links can be higher than their RF counterparts, whereas the RF links have greater link availability. The focus of this paper is twofold: to consider the operations of one or more iROC nodes from a networking point of view, and to suggest specific areas of research to further the field. We consider the utility of Disruption Tolerant Networking (DTN) and the Virtual Mission Operation Center (VMOC) model.

  9. 25 CFR 169.26 - Telephone and telegraph lines; radio, television, and other communications facilities.

    Science.gov (United States)

    2010-04-01

    ...; radio, television, and other communications facilities. (a) The Act of February 15, 1901 (31 Stat. 790... communication purposes, and for radio, television, and other forms of communication transmitting, relay, and... relative positions. (e) Rights-of-way for poles and lines for communication purposes, and for...

  10. Detection of Transionospheric SuperDARN HF Waves by the Radio Receiver Instrument on the enhanced Polar Outflow Probe Satellite

    Science.gov (United States)

    Gillies, R. G.; Yau, A. W.; James, H. G.; Hussey, G. C.; McWilliams, K. A.

    2014-12-01

    The enhanced Polar Outflow Probe (ePOP) Canadian small-satellite was launched in September 2013. Included in this suite of eight scientific instruments is the Radio Receiver Instrument (RRI). The RRI has been used to measure VLF and HF radio waves from various ground and spontaneous ionospheric sources. The first dedicated ground transmission that was detected by RRI was from the Saskatoon Super Dual Auroral Radar Network (SuperDARN) radar on Nov. 7, 2013 at 14 MHz. Several other passes over the Saskatoon SuperDARN radar have been recorded since then. Ground transmissions have also been observed from other radars, such as the SPEAR, HAARP, and SURA ionospheric heaters. However, the focus of this study will be on the results obtained from the SuperDARN passes. An analysis of the signal recorded by the RRI provides estimates of signal power, Doppler shift, polarization, absolute time delay, differential mode delay, and angle of arrival. By comparing these parameters to similar parameters derived from ray tracing simulations, ionospheric electron density structures may be detected and measured. Further analysis of the results from the other ground transmitters and future SuperDARN passes will be used to refine these results.

  11. Rapid Prototyping by 3D Printing for Advanced Radio Communications at 80 GHz and Above

    DEFF Research Database (Denmark)

    Salazar, Adrian Ruiz; Rommel, Simon; Anufriyev, Eldar

    2016-01-01

    This paper discusses the potential of 3D printing for the manufacturing of spiral phase plates for the generation of radio vortex beams for advanced radio communications. The design and prototyping of a number of phase plates for communications at 80GHz with radio vortex beams is discussed...

  12. Irregular HF radio propagation on a subauroral path during magnetospheric substorms

    Directory of Open Access Journals (Sweden)

    D. V. Blagoveshchensky

    2006-08-01

    Full Text Available The impact of the main ionospheric trough, sporadic structures, gradients and inhomogeneities of the subpolar ionosphere during substorms on the signal amplitude, azimuthal angles of arrival, and propagation modes for the radio path Ottawa (Canada-St. Petersburg (Russia was considered. This subauroral path with the length of about 6600 km has approximately an east-west orientation. The main goals are to carry out numerical modeling of radio propagation for the path and to compare the model calculations with experimental results. Wave absorption and effects of focusing and divergence of rays were taken into consideration in the radio wave modeling process. The following basic results were obtained: The signal amplitude increases by 20–30 dB 1–1.5 h before the substorm expansion phase onset. At the same time the signal azimuth deviates towards north of the great circle arc for the propagation path. Compared with quiet periods there are effects due to irregularities and gradients in the area of the polar edge of the main ionospheric trough on the passing signals. Propagation mechanisms also change during substorms. The growth of signal amplitude before the substorm can be physically explained by both a decrease of the F2-layer ionization and a growth of the F2-layer height that leads to a decrease of the signal field divergence and to a drop of the collision frequency. Ionospheric gradients are also important. This increase of signal level prior to a substorm could be used for forecasting of space weather disturbed conditions.

  13. Ionospheric Modification by High Power, Obliquely Propagated HF Radio Wave Transmissions. Part 1. Experimental

    Science.gov (United States)

    1993-07-01

    frequency of the disturbing transmitter is greater than the i.. asma frequency in the ionospheric interaction region. In fact, with many practical radio...NY) lay in the Gulf of Mexico and it was not possible to use an oblique probe system similar to- the technique used by the Soviets in their...using a vertical incidence sounder at Albuquerque, New Mexico (35.11N, 106.8 0W) at the midpoint of the 2400 km path. This technique insures that the

  14. RFID Transponders' Radio Frequency Emissions in Aircraft Communication and Navigation Radio Bands

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Williams, Reuben A.; Koppen, Sandra V.; Salud, Maria Theresa P.

    2006-01-01

    Radiated emissions in aircraft communication and navigation bands are measured from several active radio frequency identification (RFID) tags. The individual tags are different in design and operations. They may also operate in different frequency bands. The process for measuring the emissions is discussed, and includes tag interrogation, reverberation chamber testing, and instrument settings selection. The measurement results are described and compared against aircraft emission limits. In addition, interference path loss for the cargo bays of passenger aircraft is measured. Cargo bay path loss is more appropriate for RFID tags than passenger cabin path loss. The path loss data are reported for several aircraft radio systems on a Boeing 747 and an Airbus A320.

  15. 49 CFR 220.29 - Statement of letters and numbers in radio communications.

    Science.gov (United States)

    2010-10-01

    ...) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.29 Statement of letters and numbers in radio communications. (a) If necessary for... 49 Transportation 4 2010-10-01 2010-10-01 false Statement of letters and numbers in...

  16. Experimental Characterization of Extremely Broadband THz Impulse Radio Communication Systems

    DEFF Research Database (Denmark)

    Yu, Xianbin; Vidal, Borja; Galili, Michael

    2015-01-01

    We experimentally characterize a ultrabroadband terahertz (THz) impulse radio system with up to 10 GHz repetition rate. THz generation and radiation are realized in an antenna-integrated uni-traveling-carrier photodiode (UTC-PD), and THz reception is implemented based on photoconductive sampling...... by using a photoconductive antenna (PCA). We analyze the performance in terms of bandwidth and the features of the THz pulses. A 15 dB bandwidth of 1 THz confirms that this THz impulse system has a great potential of supporting ultrafast data rates, eventually for Terabit wireless communication era....

  17. Coordination procedure for radio relay and communication satellite services

    Science.gov (United States)

    Eckerman, J.

    1973-01-01

    A global rain rate statistic model is used to link microwave propagation statistics to measurable rain statistics in order to develop international telecommunication site criteria for radio relay and communication satellite services that minimize interference between receivers and transmitters. This rain coordination procedure utilizes a rain storm cell size, a statistical description of the rainfall rate within the cell valid for most of the earth's surface, approximations between Raleigh scatter and constancy of precipitation with altitude, and an analytic relation between radar reflectivity and rain rate.

  18. Interpole Communication in Radio Pulsars and the Resulting Theoretical Challenges

    Science.gov (United States)

    Weltevrede, P.; Wright, G.; Johnston, S.

    2012-12-01

    Here we discuss some recent, and less recent, radio observations that demonstrate an intimate link between the emission generated by opposite magnetic poles of neutron stars. More specifically, there are examples of pulsars which show quasi-periodic brightening of the emission generated by both poles with a time delay which remains fixed on a timescale of at least years. This implies that the opposite magnetic poles do not operate independently of each other, leading to the question about the nature of the communication channel. In the case of PSR B1055-52 this time delay is very large, corresponding to a light travel distance of many times the light cylinder radius. A number of physical models are explored and significant objections can be made to each model. So the communication channel between the magnetic poles of pulsars remains elusive, although its understanding could prove crucial to understanding the large-scale structure of magnetospheres.

  19. Electron-ion temperature ratio estimations in the summer polar mesosphere when subject to HF radio wave heating

    Science.gov (United States)

    Pinedo, H.; La Hoz, C.; Havnes, O.; Rietveld, M.

    2014-10-01

    We have inferred the electron temperature enhancements above mesospheric altitudes under Polar Mesospheric Summer Echoes (PMSE) conditions when the ionosphere is exposed to artificial HF radio wave heating. The proposed method uses the dependence of the radar cross section on the electron-to-ion temperature ratio to infer the heating factor from incoherent scatter radar (ISR) power measurements above 90 km. Model heating temperatures match our ISR estimations between 90 and 130 km with 0.94 Pearson correlation index. The PMSE strength measured by the MORRO MST radar is about 50% weaker during the heater-on period when the modeled electron-to-ion mesospheric temperature is approximately 10 times greater than the unperturbed value. No PMSE weakening is found when the mesospheric temperature enhancement is by a factor of three or less. The PMSE weakening and its absence are consistent with the modeled mesospheric electron temperatures. This consistency supports to the proposed method for estimating mesospheric electron temperatures achieved by independent MST and ISR radar measurements.

  20. A COTS RF/Optical Software Defined Radio for the Integrated Radio and Optical Communications Test Bed

    Science.gov (United States)

    Nappier, Jennifer M.; Zeleznikar, Daniel J.; Wroblewski, Adam C.; Tokars, Roger P.; Schoenholz, Bryan L.; Lantz, Nicholas C.

    2017-01-01

    The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration (NASA) is investigating the merits of a hybrid radio frequency (RF) and optical communication system for deep space missions. In an effort to demonstrate the feasibility and advantages of a hybrid RF/Optical software defined radio (SDR), a laboratory prototype was assembled from primarily commercial-off-the-shelf (COTS) hardware components. This COTS platform has been used to demonstrate simultaneous transmission of the radio and optical communications waveforms through to the physical layer (telescope and antenna). This paper details the hardware and software used in the platform and various measures of its performance. A laboratory optical receiver platform has also been assembled in order to demonstrate hybrid free space links in combination with the transmitter.

  1. Localization and cooperative communication methods for cognitive radio

    Science.gov (United States)

    Duval, Olivier

    We study localization of nearby nodes and cooperative communication for cognitive radios. Cognitive radios sensing their environment to estimate the channel gain between nodes can cooperate and adapt their transmission power to maximize the capacity of the communication between two nodes. We study the end-to-end capacity of a cooperative relaying scheme using orthogonal frequency-division modulation (OFDM) modulation, under power constraints for both the base station and the relay station. The relay uses amplify-and-forward and decode-and-forward cooperative relaying techniques to retransmit messages on a subset of the available subcarriers. The power used in the base station and the relay station transmitters is allocated to maximize the overall system capacity. The subcarrier selection and power allocation are obtained based on convex optimization formulations and an iterative algorithm. Additionally, decode-and-forward relaying schemes are allowed to pair source and relayed subcarriers to increase further the capacity of the system. The proposed techniques outperforms non-selective relaying schemes over a range of relay power budgets. Cognitive radios can be used for opportunistic access of the radio spectrum by detecting spectrum holes left unused by licensed primary users. We introduce a spectrum holes detection approach, which combines blind modulation classification, angle of arrival estimation and number of sources detection. We perform eigenspace analysis to determine the number of sources, and estimate their angles of arrival (AOA). In addition, we classify detected sources as primary or secondary users with their distinct second-orde one-conjugate cyclostationarity features. Extensive simulations carried out indicate that the proposed system identifies and locates individual sources correctly, even at -4 dB signal-to-noise ratios (SNR). In environments with a high density of scatterers, several wireless channels experience nonline-of-sight (NLOS

  2. Software-Defined Ultra-wideband Radio Communications: A New RF Technology for Emergency Response Applications

    Energy Technology Data Exchange (ETDEWEB)

    Nekoogar, F; Dowla, F

    2009-10-19

    Reliable wireless communication links for local-area (short-range) and regional (long-range) reach capabilities are crucial for emergency response to disasters. Lack of a dependable communication system can result in disruptions in the situational awareness between the local responders in the field and the emergency command and control centers. To date, all wireless communications systems such as cell phones and walkie-talkies use narrowband radio frequency (RF) signaling for data communication. However, the hostile radio propagation environment caused by collapsed structures and rubble in various disaster sites results in significant degradation and attenuation of narrowband RF signals, which ends up in frequent communication breakdowns. To address the challenges of reliable radio communication in disaster fields, we propose an approach to use ultra-wideband (UWB) or wideband RF waveforms for implementation on Software Defined Radio (SDR) platforms. Ultra-wideband communications has been proven by many research groups to be effective in addressing many of the limitations faced by conventional narrowband radio technologies. In addition, LLNL's radio and wireless team have shown significant success in field deployment of various UWB communications system for harsh environments based on LLNL's patented UWB modulation and equalization techniques. Furthermore, using software defined radio platform for UWB communications offers a great deal of flexibility in operational parameters and helps the radio system to dynamically adapt itself to its environment for optimal performance.

  3. STS-37 Pilot Cameron uses SAREX to communicate amateur radio operators

    Science.gov (United States)

    1991-01-01

    STS-37 Pilot Kenneth D. Cameron, wearing Shuttle Amateur Radio Experiment (SAREX) headset (HDST), communicates with amateur radio operators and students while on aft flight deck aboard Atlantis, Orbiter Vehicle (OV) 104. SAREX provided radio transmissions between ground based amateur radio operators around the world and Cameron (call sign KB5AWP) and the other crewmembers, all of whom are licensed amateur radio operators. SAREX enabled students from all over the United States to have a chance to communicate with an astronaut in space. The cloud-covered surface of the Earth is visible above Cameron framed in the overhead window W8.

  4. Radio Synthesis Imaging - A High Performance Computing and Communications Project

    Science.gov (United States)

    Crutcher, Richard M.

    The National Science Foundation has funded a five-year High Performance Computing and Communications project at the National Center for Supercomputing Applications (NCSA) for the direct implementation of several of the computing recommendations of the Astronomy and Astrophysics Survey Committee (the "Bahcall report"). This paper is a summary of the project goals and a progress report. The project will implement a prototype of the next generation of astronomical telescope systems - remotely located telescopes connected by high-speed networks to very high performance, scalable architecture computers and on-line data archives, which are accessed by astronomers over Gbit/sec networks. Specifically, a data link has been installed between the BIMA millimeter-wave synthesis array at Hat Creek, California and NCSA at Urbana, Illinois for real-time transmission of data to NCSA. Data are automatically archived, and may be browsed and retrieved by astronomers using the NCSA Mosaic software. In addition, an on-line digital library of processed images will be established. BIMA data will be processed on a very high performance distributed computing system, with I/O, user interface, and most of the software system running on the NCSA Convex C3880 supercomputer or Silicon Graphics Onyx workstations connected by HiPPI to the high performance, massively parallel Thinking Machines Corporation CM-5. The very computationally intensive algorithms for calibration and imaging of radio synthesis array observations will be optimized for the CM-5 and new algorithms which utilize the massively parallel architecture will be developed. Code running simultaneously on the distributed computers will communicate using the Data Transport Mechanism developed by NCSA. The project will also use the BLANCA Gbit/s testbed network between Urbana and Madison, Wisconsin to connect an Onyx workstation in the University of Wisconsin Astronomy Department to the NCSA CM-5, for development of long

  5. FQPSK techniques for satellite and mobile radio communications systems

    Science.gov (United States)

    Li, Yazhuo; Tang, Jing; Tao, Xiaofeng

    2005-11-01

    A continuous phase modulation (CPM) and constant envelope modulation (CEM) alternative of Feher-Patented quadrature phase-shift keying (FQPSK) modulation technique is presented. It is found to provide good spectral efficiencies, power efficiencies, and bit error rate (BER) performance. The modulation schemes of FQPSK are described. The spectral efficiencies, BER performance are also compared with FQPSK and other modulation techniques which are widely used in current mobile and cordless radio standards. The results show that FQPSK modulated signal exhibits much less spectrum spreading than QPSK, OQPSK, and MSK, and the error probability performance of the FQPSK is superior to those in narrow-band nonlinear channels. Based on that, the system capacity and power dissipation are also analyzed for communication systems. It is found that the encoder or receiver for the FQPSK signal to be fully compatible with original I/Q modulated one. FQPSK technique is suitable for nonlinear channels, such as satellite and mobile communications systems reducing the AM/AM and AM/PM adverse effects. At last it is also attempted to extend the application in 3G (CDMA) and 4G (OFDM) mobile communications systems.

  6. Radio-wave propagation for space communications systems

    Science.gov (United States)

    Ippolito, L. J.

    1981-01-01

    The most recent information on the effects of Earth's atmosphere on space communications systems is reviewed. The design and reliable operation of satellite systems that provide the many applications in space which rely on the transmission of radio waves for communications and scientific purposes are dependent on the propagation characteristics of the transmission path. The presence of atmospheric gases, clouds, fog, precipitation, and turbulence causes uncontrolled variations in the signal characteristics. These variations can result in a reduction of the quality and reliability of the transmitted information. Models and other techniques are used in the prediction of atmospheric effects as influenced by frequency, geography, elevation angle, and type of transmission. Recent data on performance characteristics obtained from direct measurements on satellite links operating to above 30 GHz have been reviewed. Particular emphasis has been placed on the effects of precipitation on the Earth/space path, including rain attenuation, and ice particle depolarization. Other factors are sky noise, antenna gain degradation, scintillations, and bandwidth coherence. Each of the various propagation factors has an effect on design criteria for communications systems. These criteria include link reliability, power margins, noise contribution, modulation and polarization factors, channel cross talk, error rate, and bandwidth limitations.

  7. Radio Wave Propagation Handbook for Communication on and Around Mars

    Science.gov (United States)

    Ho, Christian; Golshan, Nasser; Kliore, Arvydas

    2002-01-01

    This handbook examines the effects of the Martian environment on radio wave propagation on Mars and in the space near the planet. The environmental effects include these from the Martian atmosphere, ionosphere, global dust storms, aerosols, clouds, and geomorphologic features. Relevant Martian environmental parameters were extracted from the measurements of Mars missions during the past 30 years, especially from Mars Pathfinder and Mars Global Surveyor. The results derived from measurements and analyses have been reviewed through an extensive literature search. The updated parameters have been theoretically analyzed to study their effects on radio propagation. This handbook also provides basic information about the entire telecommunications environment on and around Mars for propagation researchers, system engineers, and link analysts. Based on these original analyses, some important recommendations have been made, including the use of the Martian ionosphere as a reflector for Mars global or trans-horizon communication between future Martian colonies, reducing dust storm scattering effects, etc. These results have extended our wave propagation knowledge to a planet other than Earth; and the tables, models, and graphics included in this handbook will benefit telecommunication system engineers and scientific researchers.

  8. Full Duplex Wireless Communications for Cognitive Radio Networks

    CERN Document Server

    Cheng, Wenchi; Zhang, Hailin

    2011-01-01

    As a key in cognitive radio networks (CRNs), dynamic spectrum access needs to be carefully designed to minimize the interference and delay to the \\emph{primary} (licensed) users. One of the main challenges in dynamic spectrum access is to determine when the \\emph{secondary} (unlicensed) users can use the spectrum. In particular, when the secondary user is using the spectrum, if the primary user becomes active to use the spectrum, it is usually hard for the secondary user to detect the primary user instantaneously, thus causing unexpected interference and delay to primary users. The secondary user cannot detect the presence of primary users instantaneously because the secondary user is unable to detect the spectrum at the same time while it is transmitting. To solve this problem, we propose the full duplex wireless communications scheme for CRNs. In particular, we employ the Antennas Cancellation (AC), the RF Interference Cancellation (RIC), and the Digital Interference Cancellation (DIC) techniques for second...

  9. Practical Limits in the Sensitivity-Linearity Trade-off for Radio Telescope Front Ends in the HF and VHF-low Bands

    CERN Document Server

    Tillman, R H; Brendler, J

    2016-01-01

    Radio telescope front ends must have simultaneously low noise and sufficiently-high linearity to accommodate interfering signals. Typically these are opposing design goals. For modern radio telescopes operating in the HF (3-30 MHz) and VHF-low (30-88 MHz) bands, the problem is more nuanced in that front end noise temperature may be a relatively small component of the system temperature, and increased linearity may be required due to the particular interference problems associated with this spectrum. In this paper we present an analysis of the sensitivity-linearity trade off at these frequencies, applicable to existing commercially-available monolithic microwave integrated circuit (MMIC) amplifiers in single-ended, differential, and parallelized configurations. This analysis and associated findings should be useful in the design and upgrade of front ends for low frequency radio telescopes. The analysis is demonstrated explicitly for one of the better-performing amplifiers encountered in this study, the Mini-Ci...

  10. Radio communication for motor sports; Motor sports ni okeru musen tsushin

    Energy Technology Data Exchange (ETDEWEB)

    Ota, K. [Kenwood Corp., Tokyo (Japan)

    2000-02-01

    This paper describes general radio communication, and radio telephone and data communication for motor sports. The radio communication for racing cars is largely disturbed by car noises and peripheral noises. The adverse effect of noises caused by on-board computer on communication, and that of radio waves on a computer are unavoidable. The radio communication is also disturbed by various radio devices in a racing circuit. As disturbance measures, change of radio frequency and filtering are necessary. For the radio telephone communication between a driver and a manager or a manager and team staffs, a close-talking microphone or a microphone with a noise canceler are used to pick up proper voices from strong roaring. However, although the frequency band of engine noises is nearly equal to that of human voices, separation of voices is extremely difficult. The car data during racing are transmitted rapidly to a pit by microwave communication, and used for the planning of a race strategy in a pit. (NEDO)

  11. Incorporating the Campus Radio Station into Your Emergency Communications Plan

    Science.gov (United States)

    Johnson, Thomas C.

    2008-01-01

    Radio stations have been a mainstay of American life since the 1920s. Broadcasting primarily over AM and FM frequencies, American radio stations have been used to provide entertainment, news, weather, and advertising to the public. Beginning in 1963 and continuing until 1997, local radio stations were part of the Emergency Broadcast System (EBS)…

  12. A Simple Radio Receiver Aids Understanding of Wireless Communication

    Science.gov (United States)

    Straulino, S.; Orlando, A.

    2012-01-01

    The basic theory of radio broadcasting is discussed from an experimental point of view. First, concepts like wave modulation and tuning are explained with the use of instruments in the physics laboratory. Then, a very basic radio receiver is described and assembled, whose most important feature, like in the old "crystal radios", is the absence of…

  13. Assessing Evaporation Duct Variability In The Eastern Mediterranean Sea In Support Of Radar And Radio Communications

    Science.gov (United States)

    2016-12-01

    EVAPORATION DUCT VARIABILITY IN THE EASTERN MEDITERRANEAN SEA IN SUPPORT OF RADAR AND RADIO COMMUNICATIONS by Süleyman C. Gürbüz December 2016...MEDITERRANEAN SEA IN SUPPORT OF RADAR AND RADIO COMMUNICATIONS 5. FUNDING NUMBERS 6. AUTHOR(S) Süleyman C. Gürbüz 7. PERFORMING ORGANIZATION NAME(S...IN THE EASTERN MEDITERRANEAN SEA IN SUPPORT OF RADAR AND RADIO COMMUNICATIONS Süleyman C. Gürbüz Lieutenant Junior Grade, Turkish Navy B.S

  14. Estimation of the Potential Interference Immunity of Radio Reception with Spatial Signal Processing in Multipath Radio-Communication Channels. I. Decameter Range

    Science.gov (United States)

    Metelev, S. A.; Lvov, A. V.

    2016-09-01

    We propose a method for estimating potential interference immunity of radio reception in the multipath radio-communication channels. Using this method for the modified Watterson model of the decameter radio channel, we study the achievable interference immunity of devices with spatial signal processing.

  15. [Problems of harmonization of sanitary regulations of the electromagnetic fields of mobile radio communication equipment].

    Science.gov (United States)

    Pal'tsev, Iu P; Pokhodzeĭ, L V; Rubtsova, N B; Bogacheva, E V

    2013-01-01

    In the article there are presented data on the probable adverse effects of electromagnetic fields generated by means of mobile cellulary radio communication equipment, a comparative analysis of hygienic rating and methods of measurement of their parameters in Russia and abroad has been performed, and the ways of harmonizing hygienic rules have been outlined, the necessity of further research to risk assessment of the use of cellular radio communication devices by population and preventive measures have been substantiated.

  16. Radiation effects on communication performance of radio frequency identification tags.

    Science.gov (United States)

    Mori, Kazuyuki; Meng, Zhaowu; Kikuchi, Hirosumi; Kataoka, Yasuhide; Nakazato, Kazuhisa; Deji, Shizuhiko; Ito, Shigeki; Saze, Takuya; Hirota, Masahiro; Nishizawa, Kunihide

    2010-11-01

    Radioactive materials (sources) are managed by bookkeeping and stocktaking. The radiation protection section staffs should check the sources manually. Annual effective dose concerning stocktaking of them are estimated at some mSv concerning fingers. A radio frequency identification (RFID) tag's absorbed dose is estimated at some dozen Gy. RFID for stocktaking automatically was devised. Radiation effects on the communication performance of RFID tags were investigated by using response times and read ranges as indices. The RFID system was composed of a computer, a detector, and transponders (tag) consisting of an integrated circuit chip and an antenna. The tag is joined to the source for identification. The tags were irradiated at doses between 5 and 5,000 Gy by an x-ray irradiator. The response times and the read ranges were tracked from 40 to 23,200 min after irradiation. Relative read ranges fluctuated between 0.9 and 1.1 in the dose region less than 2,000 Gy, but fluctuated greatly in the dose region beyond 2,000 Gy. Malfunctioning tags appeared from 3,000 Gy, and all tags malfunctioned in the dose region over 4,500 Gy. The threshold dose leading to malfunction was determined to be 2,100 Gy. Time variation of relative read ranges was classified into four patterns. The pattern shifted from pattern 1 to 4 when the dose was increased. The relative read ranges lengthened in pattern 1. The relative read rages were approximately 1.0 in pattern 2. The read ranges tentatively shortened, then recovered in pattern 3. The tags malfunctioned in pattern 4. Once the tags malfunctioned, they never recovered their performance. Radiation enhances or deteriorates communication performance depending on dosage. Tags can spontaneously recover from radiation deterioration. The time variation of the read ranges can be illustrated by enhancement, deterioration, and recovery. The mechanism of four patterns is explained based on the variation of the frequency harmonization strength and

  17. When all else fails: 21st century Amateur Radio as an emergency communications medium.

    Science.gov (United States)

    Nollet, Kenneth E; Ohto, Hitoshi

    2013-12-01

    Twenty-first century demand for radio spectrum continues to increase with the explosive growth of wireless devices, but authorities reserve slices of the spectrum for licensed Amateur Radio operators, recognizing their value to the public, particularly with respect to providing emergency communications. Blood banking and transfusion medicine are among the specialties that should also recognize the value of Amateur Radio as an emergency communications medium, because blood collection, testing, processing, storage, and transfusion are life-saving activities that in modern times can be separated by considerable distance.

  18. The paraboloidal reflector antenna in radio astronomy and communication theory and practice

    CERN Document Server

    Baars, Jacob W M

    2007-01-01

    Reflector antennas are widely used in the microwave and millimeter wavelength domain. Radio astronomers have developed techniques of calibration of large antennas with radio astronomical methods. These have not been comprehensively described. This text aims to fill this gap. The Paraboloidal Reflector Antenna in Radio Astronomy and Communication: Theory and Practice takes a practical approach to the characterization of antennas. All calculations and results in the form of tables and figures have been made with Mathematica by Wolfram Research. The reader can use the procedures for the implementation of his/her own input data. The book should be of use to all who are involved in the design and calibration of large antennas, like ground station managers and engineers, practicing radio astronomers, and finally, graduate students in radio astronomy and communication technology.

  19. Experimental Investigation Related To Some Predicted Results Of Reliable High Frequency Radio Communication Links Between Benghazi-Libya And Cairo-Egypt.

    Directory of Open Access Journals (Sweden)

    Mohamed Yousef Ahmed Abou-Hussein

    2014-01-01

    Full Text Available In this study, the central radio propagation laboratory (CRPL method of ionospheric prediction of the National Bureau of Standards (NBS in U.S.A was used in practical calculations of the optimal working frequencies for reliable high frequency (HF radio communication links between Benghazi-Libya and Cairo-Egypt. The results were drawn in the form of curves by using the computer. The computer was used to measure the received signal level variation of frequencies 11.980 MHz, 11.785 MHz which were transmitted with a power of 250 KW, 100 KW respectively from the Egypt Arabic Republic Broadcasting station in Cairo city, directed to the North Africa and South Europe regions. The measurements were taken during daytime's for winter (December, January& February and summer (June, July & August seasons.

  20. IonRayTrace: An HF Propagation Model for Communications and Radar Applications

    Science.gov (United States)

    2014-12-01

    this report was performed by the Atmospheric Propagation Branch (Code 55280), Space and Naval Warfare Systems Center Pacific (SSC Pacific), San Diego...the 2- to 7-MHz (red), 7- to 12-MHz (green), and 12- to 17-MHz (blue) bands ..................... 9 1 1. OVERVIEW The Advanced Refractivity ...density of free electrons (102 to 104 cm-3) and has negligible refractive effect on electromagnetic waves in the HF band [5]. However, in general

  1. Implementation of wireless communication based on Software Defined Radio

    OpenAIRE

    Zhang, Lei

    2013-01-01

    In current communication systems, there are many new challenges like various competitive standards, the scarcity of frequency resource, etc., especially the development of personal wireless communication systems result the new system update faster than ever before, the conventional hardware-based wireless communication system is difficult to adapt to this situation. The emergence of SDR enabled the third revolution of wireless communication which from hardware to software and build a flexible...

  2. Next generation wireless communications using radio over fiber

    CERN Document Server

    Gomes, Nathan J; Gameiro, Atilio

    2012-01-01

    Taking a coherent and logical approach, this book describes the potential use of co-ordinated multipoint systems supported by radio over fiber. It covers an impressive breadth of topics, ranging from components, subsystem and system architecture, to network management and business perspectives. The authors show the importance of radio over fiber in eliminating or mitigating against the current, perceived barriers to the use of co-ordinated multipoint, and the drivers for standardisation activities in future mobile/wireless systems over the next few years. The book brings together the

  3. Multi-Objective Reinforcement Learning for Cognitive Radio-Based Satellite Communications

    Science.gov (United States)

    Ferreira, Paulo Victor R.; Paffenroth, Randy; Wyglinski, Alexander M.; Hackett, Timothy M.; Bilen, Sven G.; Reinhart, Richard C.; Mortensen, Dale J.

    2016-01-01

    Previous research on cognitive radios has addressed the performance of various machine-learning and optimization techniques for decision making of terrestrial link properties. In this paper, we present our recent investigations with respect to reinforcement learning that potentially can be employed by future cognitive radios installed onboard satellite communications systems specifically tasked with radio resource management. This work analyzes the performance of learning, reasoning, and decision making while considering multiple objectives for time-varying communications channels, as well as different cross-layer requirements. Based on the urgent demand for increased bandwidth, which is being addressed by the next generation of high-throughput satellites, the performance of cognitive radio is assessed considering links between a geostationary satellite and a fixed ground station operating at Ka-band (26 GHz). Simulation results show multiple objective performance improvements of more than 3.5 times for clear sky conditions and 6.8 times for rain conditions.

  4. Advanced Multimode Radio for Wireless & Mobile Broadband Communication

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Lanzani, Christian

    2009-01-01

    of a digital predistortion (DPD) block is emphasized and an adaptive polynomial approach based on cartesian to polar conversion is then proposed. Such radio architecture has successfully been implemented on a low-cost FPGA family meeting the WiMAX/LTE spectrum and Error Vector Magnitude (EVM) requirements....

  5. Radio Channel Modelling for UAV Communication over Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Nguyen, Huan Cong; Mogensen, Preben Elgaard

    2017-01-01

    The main goal of this paper is to obtain models for path loss exponents and shadowing for the radio channel between airborne Unmanned Aerial Vehicles (UAVs) and cellular networks. In this pursuit, field measurements were conducted in live LTE networks at the 800 MHz frequency band, using...

  6. Development of radio dramas for health communication pilot intervention in Canadian Inuit communities.

    Science.gov (United States)

    Racicot-Matta, Cassandra; Wilcke, Markus; Egeland, Grace M

    2016-03-01

    A mixed-methods approach was used to develop a culturally appropriate health intervention over radio within the Inuit community of Pangnirtung, Nunavut (NU), Canada. The radio dramas were developed, recorded and tested pre-intervention through the use of Participatory Process and informed by the extended elaboration likelihood model (EELM) for education-communication. The radio messages were tested in two focus groups (n = 4 and n = 5) to determine fidelity of the radio dramas to the EELM theory. Focus group feedback identified that revisions needed to be made to two characteristics required of educational programmes by the EELM theorem: first, the quality of the production was improved by adding Inuit youth recorded music and second, the homophily (relatability of characters) of radio dramas was improved by re-recording the dramas with voices of local youth who had been trained in media communication studies. These adjustments would not have been implemented had pre-intervention testing of the radio dramas not taken place and could have reduced effectiveness of the overall intervention. Therefore, it is highly recommended that media tools for health communication/education be tested with the intended target audience before commencement of programmes. Participatory Process was identified to be a powerful tool in the development and sustainability of culturally appropriate community health programming.

  7. Communication: Mode specific quantum dynamics of the F + CHD3 → HF + CD3 reaction.

    Science.gov (United States)

    Qi, Ji; Song, Hongwei; Yang, Minghui; Palma, Juliana; Manthe, Uwe; Guo, Hua

    2016-05-01

    The mode specific reactivity of the F + CHD3 → HF + CD3 reaction is investigated using an eight-dimensional quantum dynamical model on a recently developed ab initio based full-dimensional potential energy surface. Our results indicate prominent resonance structures at low collision energies and absence of an energy threshold in reaction probabilities. It was also found that excitation of the C-D stretching or CD3 umbrella mode has a relatively small impact on reactivity. On the other hand, the excitation of the C-H vibration (v1) in CHD3 is shown to significantly increase the reactivity, which, like several recent quasi-classical trajectory studies, is at odds with the available experimental data. Possible sources of the disagreement are discussed.

  8. Estimation of Potential Interference Immunity of Radio Reception with Spatial Signal Processing in Mutipath Radio-Communication Channels. Part II. Meter and Decimeter Ranges

    Science.gov (United States)

    Lvov, A. V.; Metelev, S. L.

    2016-11-01

    We propose simulation models for estimating the interference immunity of radio reception using the spatial processing of signals in the airborne and ground-based communication channels of the meter and decimeter wavelength ranges. The ultimate achievable interference immunity under various radio-wave propagation conditions is studied.

  9. Keeping Communications Flowing During Large-scale Disasters: Leveraging Amateur Radio Innovations for Disaster Medicine.

    Science.gov (United States)

    Cid, Victor H; Mitz, Andrew R; Arnesen, Stacey J

    2017-09-25

    Medical facilities may struggle to maintain effective communications during a major disaster. Natural and man-made disasters threaten connectivity by degrading or crippling Internet, cellular/mobile, and landline telephone services across wide areas. Communications among staff, between facilities, and to resources outside the disaster area may be lost for an extended time. A prototype communications system created by the National Library of Medicine (NLM) provides basic communication services that ensure essential connectivity in the face of widespread infrastructure loss. It leverages amateur radio to provide resilient email service to local users, enabling them to reach intact communications networks outside the disaster zone. Because amateur radio is inexpensive, always available, and sufficiently independent of terrestrial telecommunications infrastructure, it has often augmented telecommunications capabilities of medical facilities. NLM's solution is unique in that it provides end-user to end-user direct email communications, without requiring the intervention of a radio operator in the handling of the messages. Medical staff can exchange email among themselves and with others outside the communications blackout zone. The technology is portable, is deployable on short notice, and can be powered in a variety of ways to adapt to the circumstances of each crisis. (Disaster Med Public Health Preparedness. 2017; page 1 of 8).

  10. Cooperative device-to-device communication in cognitive radio cellular networks

    CERN Document Server

    Li, Peng

    2014-01-01

    This brief examines current research on cooperative device-to-device (D2D) communication as an enhanced offloading technology to improve the performance of cognitive radio cellular networks. By providing an extensive review of recent advances in D2D communication, the authors demonstrate that the quality of D2D links significantly affects offloading performance in cellular networks, which motivates the design of cooperative D2D communication. After presenting the architecture of cooperative D2D communication, the challenges of capacity maximization and energy efficiency are addressed by optimi

  11. A review of radio channel models for body centric communications.

    Science.gov (United States)

    Cotton, Simon L; D'Errico, Raffaele; Oestges, Claude

    2014-06-01

    The human body is an extremely challenging environment for the operation of wireless communications systems, not least because of the complex antenna-body electromagnetic interaction effects which can occur. This is further compounded by the impact of movement and the propagation characteristics of the local environment which all have an effect upon body centric communications channels. As the successful design of body area networks (BANs) and other types of body centric system is inextricably linked to a thorough understanding of these factors, the aim of this paper is to conduct a survey of the current state of the art in relation to propagation and channel models primarily for BANs but also considering other types of body centric communications. We initially discuss some of the standardization efforts performed by the Institute of Electrical and Electronics Engineers 802.15.6 task group before focusing on the two most popular types of technologies currently being considered for BANs, namely narrowband and Ultrawideband (UWB) communications. For narrowband communications the applicability of a generic path loss model is contended, before presenting some of the scenario specific models which have proven successful. The impacts of human body shadowing and small-scale fading are also presented alongside some of the most recent research into the Doppler and time dependencies of BANs. For UWB BAN communications, we again consider the path loss as well as empirical tap delay line models developed from a number of extensive channel measurement campaigns conducted by research institutions around the world. Ongoing efforts within collaborative projects such as Committee on Science and Technology Action IC1004 are also described. Finally, recent years have also seen significant developments in other areas of body centric communications such as off-body and body-to-body communications. We highlight some of the newest relevant research in these areas as well as discussing

  12. A review of radio channel models for body centric communications

    Science.gov (United States)

    Cotton, Simon L.; D'Errico, Raffaele; Oestges, Claude

    2014-06-01

    The human body is an extremely challenging environment for the operation of wireless communications systems, not least because of the complex antenna-body electromagnetic interaction effects which can occur. This is further compounded by the impact of movement and the propagation characteristics of the local environment which all have an effect upon body centric communications channels. As the successful design of body area networks (BANs) and other types of body centric system is inextricably linked to a thorough understanding of these factors, the aim of this paper is to conduct a survey of the current state of the art in relation to propagation and channel models primarily for BANs but also considering other types of body centric communications. We initially discuss some of the standardization efforts performed by the Institute of Electrical and Electronics Engineers 802.15.6 task group before focusing on the two most popular types of technologies currently being considered for BANs, namely narrowband and Ultrawideband (UWB) communications. For narrowband communications the applicability of a generic path loss model is contended, before presenting some of the scenario specific models which have proven successful. The impacts of human body shadowing and small-scale fading are also presented alongside some of the most recent research into the Doppler and time dependencies of BANs. For UWB BAN communications, we again consider the path loss as well as empirical tap delay line models developed from a number of extensive channel measurement campaigns conducted by research institutions around the world. Ongoing efforts within collaborative projects such as Committee on Science and Technology Action IC1004 are also described. Finally, recent years have also seen significant developments in other areas of body centric communications such as off-body and body-to-body communications. We highlight some of the newest relevant research in these areas as well as discussing

  13. Underwater Multi-Node Radio Communication Solutions for Planetary Exploration

    Science.gov (United States)

    Kawar, Zaid Fares Yousef; Haddad, Sanad Atef Sari; Mestariheh, Feras R. M.; Jonsson, Lars Jonas

    2015-01-01

    The exploration of the presumably life harboring subsurface ocean of Europa will provide scientists with extensive new knowledge in the search for extraterrestrial life. A highly miniaturized payload is required to penetrate a narrow passage through the thick ice crust covering Europa's surface. Underwater wireless communications may be the most viable means of communication for such exploratory missions, accounting for size and weight restrictions. This presents a challenge to achieve satisfactory data rates and a range that permits autonomous underwater vehicles (AUVs) to communicate within their region of operation, as well as with a surface lander or orbiter. This work presents thorough prototype experimentation on an underwater communication system established between several nodes using RF signals. During an eight-week internship experience at NASA's Ames Research Center in September-October 2014, our team developed a Europa exploration mission concept, built representative hardware, and carried out tests to assess the feasibility of key aspects of the concept. Experiments demonstrating the viability of RF communication underwater comprised inspecting the effect of depth and horizontal distance on signal strength as well as the optimum positioning of antennas. To test the system's performance, two submersibles were designed and built. A commercially available remotely operated vehicle (ROV) was also modified and used as a main communication node. The two submersibles were wirelessly connected and accommodated sensors capable of characterizing water properties and equipped with 2.4 GHz, 1 mW transceivers to communicate the measured data. The communication procedure is that the main communication node requests the collected data from the two submersibles when in range and receives it instantly through RF. This work models what may take place during an actual mission to Europa. The developed mission concept involved a hybrid communication system consisting of

  14. Executive summary. [application of laser oriented and radio frequency techniques for space communication

    Science.gov (United States)

    1973-01-01

    The scope of Technology Forecasting for Space Communications is very wide, covering virtually every technology that can directly or indirectly affect space communications. The assigned effort, however, was directed toward a series of studies which individually examined important aspects of space communications and which collectively was interrelated. The contributions of the individual tasks and their interrelationship are indicated. The total effort of the tasks was fairly evenly divided between laser oriented and radio frequency tasks. The investigations show that laser communications have a current state of the art which would allow operational systems to be implemented in the 1975 to 1980 time frame. Further, these systems, when operated over ranges in the order of synchronous ranges (42,000 km)and transmitting data rates of 10 to the 8th power 10 to the 9th power bits per second will have a smaller total weight impact on a spacecraft than do radio systems.

  15. A New Signaling Architecture THREP with Autonomous Radio-Link Control for Wireless Communications Systems

    Science.gov (United States)

    Hirono, Masahiko; Nojima, Toshio

    This paper presents a new signaling architecture for radio-access control in wireless communications systems. Called THREP (for THREe-phase link set-up Process), it enables systems with low-cost configurations to provide tetherless access and wide-ranging mobility by using autonomous radio-link controls for fast cell searching and distributed call management. A signaling architecture generally consists of a radio-access part and a service-entity-access part. In THREP, the latter part is divided into two steps: preparing a communication channel, and sustaining it. Access control in THREP is thus composed of three separated parts, or protocol phases. The specifications of each phase are determined independently according to system requirements. In the proposed architecture, the first phase uses autonomous radio-link control because we want to construct low-power indoor wireless communications systems. Evaluation of channel usage efficiency and hand-over loss probability in the personal handy-phone system (PHS) shows that THREP makes the radio-access sub-system operations in a practical application model highly efficient, and the results of a field experiment show that THREP provides sufficient protection against severe fast CNR degradation in practical indoor propagation environments.

  16. Radio resource management for next generation mobile communication systems

    DEFF Research Database (Denmark)

    Wang, Hua

    technological novelties. Those technological breaks impose significant challenges on the design of advanced and completely new Radio Resource Management (RRM) algorithms, such as channel assignments and packet scheduling. Among the emerging technologies for broadband wireless access, special attention has been...... paid on IEEE 802.16 based technology, also known as WiMAX, for its capability to support high transmission rates and diverse QoS requirements. The objective of this Ph.D. thesis has two-fold: to design advanced RRM algorithms with different QoS support in single-hop 802.16j relay network, from physical...

  17. A History of Radio Communications in the Baltimore District

    Science.gov (United States)

    1974-09-30

    K3AKN AA3AKN WAYNE L. LEITER THOMPSONTOWN, PA. Wayne has been a licensed amateur since 1957 and a member of the Susquehanna Emergency Net since...1959. He is shown here with his radio equipment including a Heathkit m\\1-l2 transceiver, which he uses on the net. Since Wayne retired, he finds...WA3GUB BAeD BALTIMORE COUNTY CIVIL DEFENSE TOWSON , MD. I BALTI110RE COUNTY CD HEADQUARTERS, Towson , Maryland J. Alan Nollmeyer, W3YVQ, RACES

  18. A low-power photovoltaic system with energy storage for radio communications: Description and design methodology

    Science.gov (United States)

    Chapman, C. P.; Chapman, P. D.; Lewison, A. H.

    1982-01-01

    A low power photovoltaic system was constructed with approximately 500 amp hours of battery energy storage to provide power to an emergency amateur radio communications center. The system can power the communications center for about 72 hours of continuous nonsun operation. Complete construction details and a design methodology algorithm are given with abundant engineering data and adequate theory to allow similar systems to be constructed, scaled up or down, with minimum design effort.

  19. The reach and effect of radio communication campaigns on condom use in Malawi.

    Science.gov (United States)

    Meekers, Dominique; Van Rossem, Ronan; Silva, Martha; Koleros, Andrew

    2007-06-01

    This study uses data from the 2004 Malawi Demographic and Health Survey to assess the reach of selected radio programs about family planning and health in Malawi and their effect on condom use and discussion of family planning. The results show that such radio programs in Malawi reach a broad audience: eight of the 12 programs were heard by at least half of the respondents, although women were less effectively reached than men. For both women and men, the radio programs were found to have a significant impact on family planning discussion with one's partner. The programs' effect on condom use was limited, however. A positive association was found with ever use of condoms, but no association was found with condom use at last intercourse. This limited impact suggests that such radio communication campaigns need to be informed by research identifying the specific constraints to current condom use in Malawi.

  20. Personal communication networks and the effects of an entertainment-education radio soap opera in Tanzania.

    Science.gov (United States)

    Mohammed, S

    2001-01-01

    The personal networks of listeners and nonlisteners to an entertainment-education radio soap opera in Tanzania are examined to determine the effects of interpersonal discussion of the soap opera's educational themes of family planning and HIV prevention. Listeners are more likely to discuss these two educational issues in their personal communication networks and are also more likely to have other listeners to the radio program in their personal communication networks. Respondents demonstrate a relatively high degree of homophily with their network partners and are more likely to discuss matters arising from the radio program with their network partners who are of similar tribal membership, religious affiliation, and gender, and those who are equally or more highly educated than themselves.

  1. Is the current level of training in the use of equipment for prehospital radio communication sufficient?

    DEFF Research Database (Denmark)

    Holm, Jimmy Højberg

    2017-01-01

    BACKGROUND: Physicians working in prehospital care are expected to handle radio communication both within their own sector as well as with other divisions of the National Emergency Services. To date, no study has been conducted on the level of training received by physicians in the use of the equ......BACKGROUND: Physicians working in prehospital care are expected to handle radio communication both within their own sector as well as with other divisions of the National Emergency Services. To date, no study has been conducted on the level of training received by physicians in the use...... of the equipment provided or on the level of competency acquired by physicians. METHODS: In order to investigate the self-assessed skill level acquired in the use of the TETRA (TErrestrial Trunked RAdio) authority radio for communication in a prehospital setting, a cross-sectional study was conducted...... setting 38% of physicians reported having received no training in the use of the equipment, while 80% of physicians reported having received one1 hour of training or less. Among the majority of physicians their current level of training was sufficient for their everyday needs for prehospital communication...

  2. Eleanor Roosevelt, the United Nations and the Role of Radio Communications

    NARCIS (Netherlands)

    Luscombe, Anya

    Eleanor Roosevelt communicated with the public through a variety of media, both before, during and following her time in the White House. In 1946 she became part of the US delegation to the newly formed United Nations and she used newspaper columns, speeches and radio broadcasts to converse with

  3. Eleanor Roosevelt, the United Nations and the Role of Radio Communications

    NARCIS (Netherlands)

    Luscombe, Anya

    2016-01-01

    Eleanor Roosevelt communicated with the public through a variety of media, both before, during and following her time in the White House. In 1946 she became part of the US delegation to the newly formed United Nations and she used newspaper columns, speeches and radio broadcasts to converse with cit

  4. Optimal One Bit Time Reversal For UWB Impulse Radio In Multi-User Wireless Communications

    DEFF Research Database (Denmark)

    Nguyen, Hung Tuan

    2008-01-01

    In this paper, with the purpose of further reducing the complexity of the system, while keeping its temporal and spatial focusing performance, we investigate the possibility of using optimal one bit time reversal (TR) system for impulse radio ultra wideband multi-user wireless communications...

  5. Application of IRI-Plas in Ionospheric Tomography and HF Communication Studies with Assimilation of GPS-TEC

    Science.gov (United States)

    Arikan, Feza; Gulyaeva, Tamara; Sezen, Umut; Arikan, Orhan; Toker, Cenk; Hakan Tuna, MR.; Erdem, Esra

    2016-07-01

    International Reference Ionosphere is the most acknowledged climatic model of ionosphere that provides electron density profile and hourly, monthly median values of critical layer parameters of the ionosphere for a desired location, date and time between 60 to 2,000 km altitude. IRI is also accepted as the International Standard Ionosphere model. Recently, the IRI model is extended to the Global Positioning System (GPS) satellite orbital range of 20,000 km. The new version is called IRI-Plas and it can be obtained from http://ftp.izmiran.ru/pub/izmiran /SPIM/. A user-friendly online version is also provided at www.ionolab.org as a space weather service. Total Electron Content (TEC), which is defined as the line integral of electron density on a given ray path, is an observable parameter that can be estimated from earth based GPS receivers in a cost-effective manner as GPS-TEC. One of the most important advantages of IRI-Plas is the possible input of GPS-TEC to update the background deterministic ionospheric model to the current ionospheric state. This option is highly useful in regional and global tomography studies and HF link assessments. IONOLAB group currently implements IRI-Plas as a background model and updates the ionospheric state using GPS-TEC in IONOLAB-CIT and IONOLAB-RAY algorithms. The improved state of ionosphere allows the most reliable 4-D imaging of electron density profiles and HF and satellite communication link simulations.This study is supported by TUBITAK 115E915 and joint TUBITAK 114E092 and AS CR 14/001.

  6. Applications of Microwave Photonics in Radio Astronomy and Space Communication

    Science.gov (United States)

    D'Addario, Larry R.; Shillue, William P.

    2006-01-01

    An overview of narrow band vs wide band signals is given. Topics discussed included signal transmission, reference distribution and photonic antenna metrology. Examples of VLA, ALMA, ATA and DSN arrays are given. . Arrays of small antennas have become more cost-effective than large antennas for achieving large total aperture or gain, both for astronomy and for communication. It is concluded that emerging applications involving arrays of many antennas require low-cost optical communication of both wide bandwidth and narrow bandwidth; development of round-trip correction schemes enables timing precision; and free-space laser beams with microwave modulation allow structural metrology with approx 100 micrometer precision over distances of 200 meters.

  7. The Sandblaster Software-Defined Radio Platform for Mobile 4G Wireless Communications

    Directory of Open Access Journals (Sweden)

    V. Surducan

    2009-01-01

    Full Text Available We present a tier 2 Software Defined-Radio platform (SDR, built around the latest Sandbridge Technologies' multithreaded Digital Signal Processor (DSP SB3500, along with the description of major design steps taken to ensure the best radio link and computational performance. This SDR platform is capable of executing 4G wireless communication standards such as WiMAX Wave 2, WLAN 802.11 g, and LTE. Performance results for WiMAX are presented in the conclusion section.

  8. Numerical arc segmentation algorithm for a radio conference - A software tool for communication satellite systems planning

    Science.gov (United States)

    Whyte, W. A.; Heyward, A. O.; Ponchak, D. S.; Spence, R. L.; Zuzek, J. E.

    1988-01-01

    A detailed description of a Numerical Arc Segmentation Algorithm for a Radio Conference (NASARC) software package for communication satellite systems planning is presented. This software provides a method of generating predetermined arc segments for use in the development of an allotment planning procedure to be carried out at the 1988 World Administrative Radio Conference (WARC - 88) on the use of the GEO and the planning of space services utilizing GEO. The features of the NASARC software package are described, and detailed information is given about the function of each of the four NASARC program modules. The results of a sample world scenario are presented and discussed.

  9. Survey of Green Radio Communications Networks: Techniques and Recent Advances

    Directory of Open Access Journals (Sweden)

    Mohammed H. Alsharif

    2013-01-01

    Full Text Available Energy efficiency in cellular networks has received significant attention from both academia and industry because of the importance of reducing the operational expenditures and maintaining the profitability of cellular networks, in addition to making these networks “greener.” Because the base station is the primary energy consumer in the network, efforts have been made to study base station energy consumption and to find ways to improve energy efficiency. In this paper, we present a brief review of the techniques that have been used recently to improve energy efficiency, such as energy-efficient power amplifier techniques, time-domain techniques, cell switching, management of the physical layer through multiple-input multiple-output (MIMO management, heterogeneous network architectures based on Micro-Pico-Femtocells, cell zooming, and relay techniques. In addition, this paper discusses the advantages and disadvantages of each technique to contribute to a better understanding of each of the techniques and thereby offer clear insights to researchers about how to choose the best ways to reduce energy consumption in future green radio networks.

  10. Polarization features of the ELF emissions excited in the outer ionosphere through modification of the ionospheric F-region by high-power HF radio emission

    Science.gov (United States)

    Belov, Alexey

    indent=1cm The results of in-situ measurements performed by the onboard equipment of the DEMETER satellite show that the guided ELF emissions can be excited through modification of the ionospheric F-region by high-power HF radio emission from the SURA heating facility. The power spectra of the excited ELF waves have a sharp upper frequency cutoff at the local proton gyrofrequency. In this work, we study the propagation and polarization characteristics of the observed ELF emissions using multicomponent measurement of electric and magnetic fields from the DEMETER satellite. For analysis we make use of singular value decomposition (SVD) technique. It is shown that the polar angle of the observed emissions wave vector with respect to ambient magnetic field is less than pi/6. The waves propagate upward in the left-hand-polarized mode. The wave polarization changes from right- to left-handed at the so-called crossover frequency. The obtained results improve the understanding of the generation mechanisms of observed ELF emissions. This work was supported by the Russian Foundation for Basic Research (project No. 12-02-00747-a), and the Government of the Russian Federation (contract No. 11.G34.31.0048).

  11. An Archeological Overview and Management Plan for the H.F. Denton Radio Station Property, Denton County, Texas.

    Science.gov (United States)

    1984-06-04

    Frank. 1975. Texas Plants - A Checklist and Ecological Sunmary. College Station: The Texas A & M University System, The Texas Agriculture Experiment... Ecology of North America. Urbana: University of Illinois Press. Shope, Bill. 1983. Personal communication. Facility Engineering Division, Red River Army...Ammunition Plant. Simpson, G.G. 1941. Large Pleistocene Felines of North America. American Museum Noviatiates, No. 1136:19-27. • 1945. Notes on

  12. Cognitive radio networks efficient resource allocation in cooperative sensing, cellular communications, high-speed vehicles, and smart grid

    CERN Document Server

    Jiang, Tao; Cao, Yang

    2015-01-01

    PrefaceAcknowledgmentsAbout the AuthorsIntroductionCognitive Radio-Based NetworksOpportunistic Spectrum Access NetworksCognitive Radio Networks with Cooperative SensingCognitive Radio Networks for Cellular CommunicationsCognitive Radio Networks for High-Speed VehiclesCognitive Radio Networks for a Smart GridContent and OrganizationTransmission Slot Allocation in an Opportunistic Spectrum Access NetworkSingle-User Single-Channel System ModelProbabilistic Slot Allocation SchemeOptimal Probabilistic Slot AllocationBaseline PerformanceExponential DistributionHyper-Erlang DistributionPerformance An

  13. Radio propagation and adaptive antennas for wireless communication networks

    CERN Document Server

    Blaunstein, Nathan

    2014-01-01

    Explores novel wireless networks beyond 3G, and advanced 4G technologies, such as MIMO, via propagation phenomena and the fundamentals of adapted antenna usage.Explains how adaptive antennas can improve GoS and QoS for any wireless channel, with specific examples and applications in land, aircraft and satellite communications.Introduces new stochastic approach based on several multi-parametric models describing various terrestrial scenarios, which have been experimentally verified in different environmental conditionsNew chapters on fundamentals of wireless networks, cellular and non-cellular,

  14. VibeComm: radio-free wireless communication for smart devices using vibration.

    Science.gov (United States)

    Hwang, Inhwan; Cho, Jungchan; Oh, Songhwai

    2014-11-10

    This paper proposes VibeComm, a novel communication method for smart devices using a built-in vibrator and accelerometer. The proposed approach is ideal for low-rate off-line communication, and its communication medium is an object on which smart devices are placed, such as tables and desks. When more than two smart devices are placed on an object and one device wants to transmit a message to the other devices, the transmitting device generates a sequence of vibrations. The vibrations are propagated through the object on which the devices are placed. The receiving devices analyze their accelerometer readings to decode incoming messages. The proposed method can be the alternative communication method when general types of radio communication methods are not available. VibeComm is implemented on Android smartphones, and a comprehensive set of experiments is conducted to show its feasibility.

  15. VibeComm: Radio-Free Wireless Communication for Smart Devices Using Vibration

    Directory of Open Access Journals (Sweden)

    Inhwan Hwang

    2014-11-01

    Full Text Available This paper proposes VibeComm, a novel communication method for smart devices using a built-in vibrator and accelerometer. The proposed approach is ideal for low-rate off-line communication, and its communication medium is an object on which smart devices are placed, such as tables and desks. When more than two smart devices are placed on an object and one device wants to transmit a message to the other devices, the transmitting device generates a sequence of vibrations. The vibrations are propagated through the object on which the devices are placed. The receiving devices analyze their accelerometer readings to decode incoming messages. The proposed method can be the alternative communication method when general types of radio communication methods are not available. VibeComm is implemented on Android smartphones, and a comprehensive set of experiments is conducted to show its feasibility.

  16. Modeling of Reverberation Effects for Radio Localization and Communications

    DEFF Research Database (Denmark)

    Steinböck, Gerhard

    2013-01-01

    in indoor environments. We show that this component carries a significant portion of the total received power. Thus, the accurate modeling of it is of prime importance for both communication and positioning. To clarify the cause of the diffuse component we first experimentally investigate the spread...... into a distance dependent model of the delay power spectrum, which we then validate experimentally. From this model we derive secondary models that predict the received power, the mean delay, the rms delay spread and the kurtosis versus distance. The behavior of the diffuse component versus distance in indoor...... in the diffuse power due to opening windows, the presence of people or by changing the size of the room. As an example of the benefits of modeling the diffuse component in indoor environments we present a study of the performance of a positioning estimator that jointly utilizes the secondary models of received...

  17. Experimental implant communication of high data rate video using an ultra wideband radio link.

    Science.gov (United States)

    Chávez-Santiago, Raúl; Balasingham, Ilangko; Bergsland, Jacob; Zahid, Wasim; Takizawa, Kenichi; Miura, Ryu; Li, Huan-Bang

    2013-01-01

    Ultra wideband (UWB) is one of the radio technologies adopted by the IEEE 802.15.6™-2012 standard for on-body communication in body area networks (BANs). However, a number of simulation-based studies suggest the feasibility of using UWB for high data rate implant communication too. This paper presents an experimental verification of said predictions. We carried out radio transmissions of H.264/1280×720 pixels video at 80 Mbps through a UWB multiband orthogonal frequency division multiplexing (MB-OFDM) interface in a porcine chirurgical model. The results demonstrated successful transmission up to a maximum depth of 30 mm in the abdomen and 33 mm in the thorax within the 4.2-4.8 GHz frequency band.

  18. Analysis of the Realization of HF Communication System Based on IP Technology%浅析基于IP技术的短波通信组网实现

    Institute of Scientific and Technical Information of China (English)

    郭奇锋

    2016-01-01

    HF communication with its communication distance, it is difficult to completely destroy, easy maintenance and other characteristics, has been widely used in China and other countries in the world communication field. But in the use process, HF communication is still exists for the problem using the narrow frequency band, the communication capacity is small, the channel quality is susceptible to electromagnetic interference and single business etc.. With the development of information technology and mature, the use of IP technology, HF communication can build a normal operation of the information transmission and exchange platform, formed "to network" security, "to network" blind compensation, multi point large range with in the shortwave communication network access.%短波通信以其通信距离远、难以彻底摧毁、便于维护等特点,在我国以及世界各国通信领域得到了广泛应用。但是在使用过程中,短波通信仍存在可供使用频段窄,通信容量小,信道质量易受电磁干扰,业务单一等问题。随着信息技术的发展和成熟,利用IP技术,短波通信可以构建一个常态化运行的信息传输和交换平台,形成以网保障,以网补盲,多点大范围随遇接入的短波通信网络。

  19. RFID Transponders' RF Emissions in Aircraft Communication and Navigation Radio Bands

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Koppen Sandra V.; Fersch, Mariatheresa S.

    2008-01-01

    Radiated emission data in aircraft communication and navigation bands are presented for several active radio frequency identification (RFID) tags. The individual tags are different in design, operation and transmitting frequencies. The process for measuring the tags emissions in a reverberation chamber is discussed. Measurement issues dealing with tag interrogation, low level measurement in the presence of strong transmissions, and tags low duty factors are discussed. The results show strong emissions, far exceeding aircraft emission limits and can be of potential interference risks.

  20. Control and Non-Payload Communications Generation 1 Prototype Radio Flight Test Report

    Science.gov (United States)

    Shalkhauser, Kurt A.; Young, Daniel P.; Bretmersky, Steven C.; Ishac, Joseph A.; Walker, Steven H.; Griner, James H.; Kachmar, Brian A.

    2014-01-01

    Unmanned aircraft (UA) represent a new capability that will provide a variety of services in the Government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized because of the lack of a common understanding of what is required to safely operate Unmanned Aircraft Systems in the National Airspace System (UAS in the NAS). The desire and ability to fly UA is of increasing urgency. The application of UA to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UA to the NAS. Existing Federal Aviation Regulations, procedures, and technologies do not allow routine UA access to the NAS. Access to the NAS is hampered by challenges such as the lack of an onboard pilot to see and avoid other aircraft; the ability of a single pilot or operator to control multiple UA; the reliance on command and control (C2) links; the altitudes, speeds, and duration at which the aircraft fly; and the wide variation in UA size and performance. NASA is working with other Government agencies to provide solutions that reduce technical barriers and make access to the NAS routine. This goal will be accomplished through system-level integration of key concepts, technologies, or procedures and through demonstrations of these integrated capabilities in an operationally relevant environment. This project provides an opportunity to transition the acquired empirical data and knowledge to the Federal Aviation Administration and other stakeholders to help them define the requirements for routine UA access to the NAS.Radio communications channels for UA are currently managed through exceptions and use either Department of Defense frequencies for line-of-sight (LOS) and satellite-based communications links, low-power LOS links in amateur bands, or unlicensed Industrial/Scientific/Medical (ISM) frequencies. None of these frequency bands are designated for safety and

  1. Communications, Navigation, and Timing Constraints for the Solar Imaging Radio Array (SIRA)

    Science.gov (United States)

    Lemaster, E. A.; Byler, E. A.; Aschwanden, M. J.

    2003-12-01

    The Solar Imaging Radio Array (SIRA) is a proposed NASA mission to measure solar radio emissions in the 30kHz to 30MHz region of the electromagnetic spectrum. The baseline design consists of 16 separated spacecraft in an irregular pattern several kilometers across. Each spacecraft is equipped with a pair of crossed dipole antennas that together form a 16-element radio interferometer for Fourier-type image reconstruction (120 baselines in the UV-plane). The required close coordination between this formation of spacecraft places many unique constraints on the SIRA communications, navigation, control, and timing architectures. Current specifications call for knowledge of the relative locations of the spacecraft to approximately meter-level accuracy in order to maintain primary instrument resolution. Knowledge of the relative timing differences between the clocks on the spacecraft must likewise be maintained to tens of nanoseconds or better. This in turn sets a minimum bound on the regularity of communications updates between spacecraft. Although the actual positions of the spacecraft are not tightly constrained, enough control authority and system autonomy must be present to keep the spacecraft from colliding due to orbital perturbations. Each of these constraints has an important effect on the design of the architecture for the entire array. This paper examines the engineering requirements and design tradeoffs for the communications, navigation, and timing architectures for SIRA. Topics include the choice of navigation sensor, communications methodology and modulation schemes, and clock type to meet the overall system performance goals while overcoming issues such as communications dynamic range, bandwidth limitations, power constraints, available antenna beam patterns, and processing limitations. In addition, this paper discusses how the projected use of smaller spacecraft buses with their corresponding payload and cost limits has important consequences for the

  2. Reconfigurable Transceiver and Software-Defined Radio Architecture and Technology Evaluated for NASA Space Communications

    Science.gov (United States)

    Reinhart, Richard C.; Kacpura, Thomas J.

    2004-01-01

    The NASA Glenn Research Center is investigating the development and suitability of a software-based open-architecture for space-based reconfigurable transceivers (RTs) and software-defined radios (SDRs). The main objectives of this project are to enable advanced operations and reduce mission costs. SDRs are becoming more common because of the capabilities of reconfigurable digital signal processing technologies such as field programmable gate arrays and digital signal processors, which place radio functions in firmware and software that were traditionally performed with analog hardware components. Features of interest of this communications architecture include nonproprietary open standards and application programming interfaces to enable software reuse and portability, independent hardware and software development, and hardware and software functional separation. The goals for RT and SDR technologies for NASA space missions include prelaunch and on-orbit frequency and waveform reconfigurability and programmability, high data rate capability, and overall communications and processing flexibility. These operational advances over current state-of-art transceivers will be provided to reduce the power, mass, and cost of RTs and SDRs for space communications. The open architecture for NASA communications will support existing (legacy) communications needs and capabilities while providing a path to more capable, advanced waveform development and mission concepts (e.g., ad hoc constellations with self-healing networks and high-rate science data return). A study was completed to assess the state of the art in RT architectures, implementations, and technologies. In-house researchers conducted literature searches and analysis, interviewed Government and industry contacts, and solicited information and white papers from industry on space-qualifiable RTs and SDRs and their associated technologies for space-based NASA applications. The white papers were evaluated, compiled, and

  3. High-Sensitivity Phased Arrays for Radio Astronomy and Satellite Communications

    Science.gov (United States)

    Diao, Junming

    Radio astronomy is used to study stars, galaxies, black holes and gas clouds radiation at radio frequencies. Detecting extremely weak signals from deep space radio sources requires high sensitive feed system associated with large dish antennas. The key figure of merit is survey speed, or the time required to map a region of the sky to a given source flux density. Survey speed is proportional to the frequency bandwidth, the field of view or observable region of the sky, and the squared sensitivity, where sensitivity is related to reflector aperture efficiency and system noise temperature. Compared to the traditional single feed, phased array feeds with significantly expanded field of view are considered as the next generation feed for radio telescope. This dissertation outlines the design, analysis and measurement of high sensitivity L-band and mm-wave phased array feeds for the 100-meter Green Bank Telescope. Theoretical works for radio astronomy includes design guideline for high sensitivity phased array feed, fundamental frequency bandwidth limit, array antenna loss influenced by mutual coupling and beamformer coefficients and possibility of superdirectivity for radio telescopes and other antennas. These study are helpful to understand and guide the design of a phased array feed system. In the absence of dish antennas, sparse phased arrays with aperiodic structure have been developed for satellite communications. A compromise between the peak side lobe level, array element density, directivity and design complexity is studied. We have found that the array peak side lobe level can be reduced by enhancing the array element direction at the main lobe direction, increasing the array element density and enlarging the array size. A Poynting streamline approach develops to understand the properties of a receiving antenna and the mutual coupling effects between array elements. This method has been successfully used to generate effective area shape for many types of

  4. Resource Dependent Radio Allocation For Battlefield Communications - A Data Model Approach

    Directory of Open Access Journals (Sweden)

    Gregor Thomeczek

    2014-10-01

    Full Text Available Network Enabled Capability (NEC and the Land Open Systems Architecture (LOSA are novel approaches to enable interoperability between a heterogeneous collection of assets in the battlefield. These paradigms utilise an underlying network for cooperation between deployed battlefield equipment. NEC and LOSA have great potential to transform military communications and enhance integrated survivability as well as situational awareness, but the Achilles’ heel of NEC and LOSA is the wireless spectrum over which they must communicate. A noisy and dynamic battlefield wireless spectrum as well as an array of heterogeneous wireless communications equipment handling multiple types of data with different Quality of Service (QoS requirements requires a system which manages and allocates these communication resources effectively. This paper presents the High Availability Wireless Communications (HAWC system, a hardware agnostic communications controller middleware to manage any combination of existing and future multiband wireless resources. The system utilises a vehicle’s data model to gather information about available radio resources and enable LOSA by meeting communications data requirements and delivering appropriate QoS to the appropriate traffic in a fleet of vehicles. The functionality of the system is verified by using behavioural simulation on a virtual battlefield.

  5. Communicating astronomy in a small island state: The unique role of the Mauritius Radio Telescope

    Science.gov (United States)

    Saddul-Hauzaree, S.

    2008-06-01

    The Mauritius Radio Telescope (MRT) is a 2 km x 1 km T-shaped aperture synthesis array that can generate radio images of the southern sky at 151.6 MHz. The sky surveyed can be in the declination range of -70o to -10o. It is located at Bras d'Eau, northeast of Mauritius at latitude 20oS and longitude 60oE. The MRT is a joint project of the University of Mauritius, the Indian Institute of Astrophysics and the Raman Research Institute. One of the main objectives of the MRT is to generate public interest in astronomy. Thus, it is involved in a wide range of onsite outreach activities for young school children. More mature students visiting the telescope learn about sky observation with a radio telescope, get to explore some sets of data, interact with the scientific personnel, get the opportunity to have hands-on experience with image manipulation and can ask a lot of questions on astronomy. This poster gives an overview of the Mauritius Radio Telescope and the attempts of MRT ito communicate astronomy to students as a process and not just as a vast expanse of knowledge. The challenges and dilemmas faced by MRT in conveying astronomy to the general public in a small island state are investigated and presented.

  6. A Modified Energy Detection Based Spectrum Sensing Algorithm for Green Cognitive Radio Communication

    Directory of Open Access Journals (Sweden)

    Sidra Rajput

    2015-10-01

    Full Text Available Spectrum Sensing is the first and fundamental function of Cognitive Cycle which plays a vital role in the success of CRs (Cognitive Radios. Spectrum Sensing indicate the presence and absence of PUs (Primary Users in RF (Radio Frequency spectrum occupancy measurements. In order to correctly determine the presence and absence of Primary Users, the algorithms in practice include complex mathematics which increases the computational complexity of the algorithm, thus shifted the CRs to operate as ?green? communication systems. In this paper, an energy efficient and computationally less complex, energy detection based Spectrum Sensing algorithm have been proposed. The design goals of the proposed algorithm are to save the processing and sensing energies. At first, by using less MAC (Multiply and Accumulate operation, it saves the processing energy needed to determine the presence and absence of PUs. Secondly, it saves the sensing energy by providing a way to find lowest possible sensing time at which spectrum is to be sensed. Two scenarios have been defined for testing the proposed algorithm i.e. simulate detection capability of Primary Users in ideal and noisy scenarios. Detection of PUs in both of these scenarios have been compared to obtain the probability of detection. Energy Efficiency of the proposed algorithm has been proved by making performance comparison between the proposed (less complex algorithm and the legacy energy detection algorithm. With reduced complexity, the proposed spectrum sensing algorithm can be considered under the paradigm of Green Cognitive Radio Communication

  7. Development of data communication system with ultra high frequency radio wave for implantable artificial hearts.

    Science.gov (United States)

    Tsujimura, Shinichi; Yamagishi, Hiroto; Sankai, Yoshiyuki

    2009-01-01

    In order to minimize infection risks of patients with artificial hearts, wireless data transmission methods with electromagnetic induction or light have been developed. However, these methods tend to become difficult to transmit data if the external data transmission unit moves from its proper position. To resolve this serious problem, the purpose of this study is to develop a prototype wireless data communication system with ultra high frequency radio wave and confirm its performance. Due to its high-speed communication rate, low power consumption, high tolerance to electromagnetic disturbances, and secure wireless communication, we adopted Bluetooth radio wave technology for our system. The system consists of an internal data transmission unit and an external data transmission unit (53 by 64 by 16 mm, each), and each has a Bluetooth module (radio field intensity: 4 dBm, receiver sensitivity: -80 dBm). The internal unit also has a micro controller with an 8-channel 10-bit A/D converter, and the external unit also has a RS-232C converter. We experimented with the internal unit implanted into pig meat, and carried out data transmission tests to evaluate the performance of this system in tissue thickness of up to 3 mm. As a result, data transfer speeds of about 20 kbps were achieved within the communication distance of 10 m. In conclusion, we confirmed that the system can wirelessly transmit the data from the inside of the body to the outside, and it promises to resolve unstable data transmission due to accidental movements of an external data transmission unit.

  8. Control and Non-Payload Communications (CNPC) Prototype Radio - Generation 2 Flight Test Report

    Science.gov (United States)

    Ishac, Joseph A.; Iannicca, Dennis C.; Shalkhauser, Kurt A.; Kachmar, Brian A.

    2014-01-01

    NASA Glenn Research Center conducted a series of flight tests for the purpose of evaluating air-to-ground communications links for future unmanned aircraft systems (UAS). The primary objective of the test effort was to evaluate the transition of the aircraft communications from one ground station to the next, and to monitor data flow during the "hand-off" event. To facilitate the testing, ground stations were installed at locations in Cleveland, Ohio and Albany, Ohio that each provides line-of-sight radio communications with an overflying aircraft. This report describes results from the flight tests including flight parameters, received signal strength measurements, data latency times, and performance observations for the air-to-ground channel.

  9. OptoRadio: a method of wireless communication using orthogonal M-ary PSK (OMPSK) modulation

    Science.gov (United States)

    Gaire, Sunil Kumar; Faruque, Saleh; Ahamed, Md. Maruf

    2016-09-01

    Laser based radio communication system, i.e. OptoRadio, using Orthogonal M-ary PSK Modulation scheme is presented in this paper. In this scheme, when a block of data needs to be transmitted, the corresponding block of biorthogonal code is transmitted by means of multi-phase shift keying. At the receiver, two photo diodes are cross coupled. The effect is that the net output power due to ambient light is close to zero. The laser signal is then transmitted only into one of the receivers. With all other signals being cancelled out, the laser signal is an overwhelmingly dominant signal. The detailed design, bit error correction capabilities, and bandwidth efficiency are presented to illustrate the concept.

  10. Impulse Radio Ultra-Wideband Communication Over Free-Space Optical Links

    CERN Document Server

    Davaslioglu, Kemal

    2013-01-01

    A composite impulse radio ultra-wideband (IR-UWB) communication system is presented. The proposed system model aims to transmit UWB pulses over several kilometers through free-space optical (FSO) links and depending on the link design, the electrical estimates of the FSO system can be directly used or distributed to end-user through radio-frequency (RF) links over short ranges. However, inhomogeneities on the FSO transmission path cause random fluctuations in the received signal intensity and these effects induced by atmospheric turbulence closely effect the system performance. Several distinct probability distributions based on experimental measurements are used to characterize FSO channels and using these probabilistic models, detection error probability analysis of the proposed system for different link designs are carried out under weak, moderate and strong turbulence conditions. The results of the analysis show that depending on the atmospheric conditions, system performance of the composite link can hav...

  11. Radio frequency interference protection of communications between the Deep Space Network and deep space flight projects

    Science.gov (United States)

    Johnston, D. W. H.

    1981-01-01

    The increasing density of electrical and electronic circuits in Deep Space Station systems for computation, control, and numerous related functions has combined with the extension of system performance requirements calling for higher speed circuitry along with broader bandwidths. This has progressively increased the number of potential sources of radio frequency interference inside the stations. Also, the extension of spectrum usage both in power and frequency as well as the greater density of usage at all frequencies for national and international satellite communications, space research, Earth resource operations and defense, and particularly the huge expansion of airborne electronic warfare and electronic countermeasures operations in the Mojave area have greatly increased the potential number and severity of radio frequency interference incidents. The various facets of this problem and the efforts to eliminate or minimize the impact of interference on Deep Space Network support of deep space flight projects are described.

  12. Modern HF Communications.

    Science.gov (United States)

    1983-05-01

    vertically directed pulRe,’ radar , measures the delay time of the reflected siqnals in the frequency ranqe 1-20 MHz. This delay time is converted to a...qensitive and sophisticated iH or UHF- radars which detect weak reflections from plasma irregularit ies. There are ooil a few such installations in operation...terms of a few measurable parameeprs, so that the raytracing through the simplified model ionosphere yields realistic signal characteristics, for

  13. Multi-carrier transmission for hybrid radio frequency with optical wireless communications

    Science.gov (United States)

    Wang, Gang; Chen, Genshe; Shen, Dan; Pham, Khanh; Blasch, Erik; Nguyen, Tien M.

    2015-05-01

    Radio frequency (RF) wireless communication is reaching its capacity to support large data rate transmissions due to hardware constraints (e.g., silicon processes), software strategies (e.g., information theory), and consumer desire for timely large file exchanges (e.g., big data and mobile cloud computing). A high transmission rate performance must keep pace with the generated huge volumes of data for real-time processing. Integrated RF and optical wireless communications (RF/OWC) could be the next generation transmission technology to satisfy both the increased data rate exchange and the communications constraints. However, with the promising benefits of RF/OWC, challenges remain to fully develop hybrid RF with wireless optical communications such as uniform waveform design for information transmission and detection. In this paper, an orthogonal frequency division multiplexing (OFDM) transmission scheme, which widely employed in RF communications, is developed for optical communications. The traditional high peak-to-average power ratio (PAPR) in OFDM is reduced to improve system performance. The proposed multi-carrier waveform is evaluated with a frequency-selective fading channel. The results demonstrate that bit error rate (BER) performance of our proposed optical OFDM transmission technique outperforms the traditional OWC on-off keying (OOK) transmission scheme.

  14. The Hitachi and Takahagi 32 m radio telescopes: Upgrade of the antennas from satellite communication to radio astronomy

    Science.gov (United States)

    Yonekura, Yoshinori; Saito, Yu; Sugiyama, Koichiro; Soon, Kang Lou; Momose, Munetake; Yokosawa, Masayoshi; Ogawa, Hideo; Kimura, Kimihiro; Abe, Yasuhiro; Nishimura, Atsushi; Hasegawa, Yutaka; Fujisawa, Kenta; Ohyama, Tomoaki; Kono, Yusuke; Miyamoto, Yusuke; Sawada-Satoh, Satoko; Kobayashi, Hideyuki; Kawaguchi, Noriyuki; Honma, Mareki; Shibata, Katsunori M.; Sato, Katsuhisa; Ueno, Yuji; Jike, Takaaki; Tamura, Yoshiaki; Hirota, Tomoya; Miyazaki, Atsushi; Niinuma, Kotaro; Sorai, Kazuo; Takaba, Hiroshi; Hachisuka, Kazuya; Kondo, Tetsuro; Sekido, Mamoru; Murata, Yasuhiro; Nakai, Naomasa; Omodaka, Toshihiro

    2016-10-01

    The Hitachi and Takahagi 32 m radio telescopes (former satellite communication antennas) were so upgraded as to work at 6, 8, and 22 GHz. We developed the receiver systems, IF systems, back-end systems (including samplers and recorders), and reference systems. We measured the performance of the antennas. The system temperature including the atmosphere toward the zenith, T_sys^{ast }, is measured to be ˜30-40 K for 6 GHz and ˜25-35 K for 8 GHz. T_sys^{ast } for 22 GHz is measured to be ˜40-100 K in winter and ˜150-500 K in summer seasons, respectively. The aperture efficiency is 55%-75% for Hitachi at 6 GHz and 8 GHz, and 55%-65% for Takahagi at 8 GHz. The beam sizes at 6 GHz and 8 GHz are ˜4.6° and ˜3.8°, respectively. The side-lobe level is less than 3%-4% at 6 and 8 GHz. Pointing accuracy was measured to be better than ˜0.3° for Hitachi and ˜0.6° for Takahagi. We succeeded in VLBI observations in 2010 August, indicating good performance of the antenna. We started single-dish monitoring observations of 6.7 GHz methanol maser sources in 2012 December, and found several new sources showing short-term periodic variation of the flux density.

  15. HF Interference, Procedures and Tools (Interferences HF, procedures et outils)

    Science.gov (United States)

    2007-06-01

    such sources. The existing HF background noise possibly may be increased via ground wave and/or sky wave propagation. Increase of the existing HF...télécommunications filaires à large bande. Les télécommunications via le réseau électrique courant, dites PowerLine Communications (PLT ou PLC) et diverses...cumulative de nombreuses sources de même type. Le bruit de fond HF existant risque d’être augmenté par propagation de l’onde terrestre et/ou aérienne

  16. Wearable ECG Based on Impulse-Radio-Type Human Body Communication.

    Science.gov (United States)

    Wang, Jianqing; Fujiwara, Takuya; Kato, Taku; Anzai, Daisuke

    2016-09-01

    Human body communication (HBC) provides a promising physical layer for wireless body area networks (BANs) in healthcare and medical applications, because of its low propagation loss and high security characteristics. In this study, we have developed a wearable electrocardiogram (ECG) which employs impulse radio (IR)-type HBC technology for transmitting vital signals on the human body in a wearable BAN scenario. The HBC-based wearable ECG has two excellent features. First, the wideband performance of the IR scheme contributed to very low radiation power so that the transceiver is easy to satisfy the extremely weak radio laws, which does not need a license. This feature can provide big convenience in the use and spread of the wearable ECG. Second, the realization of common use of sensing and transmitting electrodes based on time sharing and capacitive coupling largely simplified the HBC-based ECG structure and contributed to its miniaturization. To verify the validity of the HBC-based ECG, we evaluated its communication performance and ECG acquisition performance. The measured bit error rate, smaller than 10 (-3) at 1.25 Mb/s, showed a good physical layer communication performance, and the acquired ECG waveform and various heart-rate variability parameters in time and frequency domains exhibited good agreement with a commercially available radio-frequency ECG and a Holter ECG. These results sufficiently showed the validity and feasibility of the HBC-based ECG for healthcare applications. This should be the first time to have realized a real-time ECG transmission by using the HBC technology.

  17. Radio over fiber for wireless communications from fundamentals to advanced topics

    CERN Document Server

    Fernando, Xavier N

    2014-01-01

    A comprehensive evaluation of Fi-Wi,  enabling readers to design links using channel estimation and equalization algorithms  This book provides a detailed study of radio over fiber (ROF) based wireless communication systems, otherwise called fiber wireless (Fi-Wi) systems. This is an emerging hot topic where the abundant bandwidth of optical fiber is directly combined with the flexibility and mobility of wireless networks to provide broadband connectivity.  Its application is increasing because of the growing demand for broadband wireless services. In such a system the transmission of the ra

  18. A MATLAB Library for Rapid Prototyping of Wireless Communications Algorithms with the Universal Software Radio Peripheral (USRP) Radio Family

    Science.gov (United States)

    2013-06-01

    Peripheral (USRP) family of radio hardware using MATLAB. This library enables fast prototyping of algorithms on SDRs. 15. SUBJECT TERMS USRP, MATLAB, GNU ...code) (301) 394-3102 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 Contents 1. Introduction 1 1.1 Challenges of GNU Radio ...multiply conjugate cc block (conjugate multiply) in GNU Radio . Arrows denote inheritance from the target block. Note the complexity of the hierarchy

  19. Impact of the integrated Radio Communication Project in Nepal, 1994-1997.

    Science.gov (United States)

    Storey, D; Boulay, M; Karki, Y; Heckert, K; Karmacharya, D M

    1999-01-01

    The Radio Communication Project (RCP) in Nepal is an ongoing, theory-based, multimedia reproductive health campaign which began in 1995. It consists of two entertainment-education radio serials (a soap opera for the general public and a dramatized distance education serial for health workers), additional radio spot advertisements and promotions, and complementary print materials. This paper examines impact data from a variety of sources, including a pre- and postpanel survey of currently married women (N = 1905), three waves of clinic-based observations of client-provider interactions (N = 240 per wave) and client exit interviews (N = 240 per wave), and 2 years of clinic service statistics, in order to draw inferences about the separate and combined effects of the RCP components. The study found increased health worker interpersonal interaction skills, improved quality of client-provider interactions, increased client self-efficacy in dealing with health workers, improved client attitudes toward health services and toward the practice of family planning, increased adoption of family planning, and increased family planning service utilization, all attributable to the RCP. The panel data allowed statistical control of the influence of predisposing factors before the campaign on postcampaign ideation and behavior. The effect of the RCP on contraceptive behavior was largely indirect through its influence on ideation. Implications for the design of integrated, multimedia, entertainment-education campaigns and integrated evaluation designs are discussed.

  20. Software Defined Electronics: A Revolutionary Change in Design and Teaching Paradigm of RF Radio Communications Systems

    Directory of Open Access Journals (Sweden)

    Géza Kolumbán

    2015-06-01

    Full Text Available Band-pass signals are used everywhere in radio communications. The band-pass property makes the substitution of each RF/microwave/ optical analog signal processing possible with a low-frequency digital one in Software Defined Electronics (SDE. In SDE, the high frequency band-pass signals are transformed into the BaseBand (BB by a universal HW device and every application is implemented in BB, entirely in software. SDE concept uses (i the lowest sampling rate attainable theoretically and (ii the same universal HW device in every application. The huge level of flexibility offered by the SW implementation is essential in many applications from cognitive radio to adaptive reconfigurable systems. This tutorial, written for interested readers who have no solid background in software defined radio, virtual instrumentation and SoC technology, surveys the SDE theory, uses a step-by-step approach for the derivation of BB equivalents and demonstrates the application of SDE concept in scientific research, prototyping and education.

  1. A Lightweight Radio Propagation Model for Vehicular Communication in Road Tunnels.

    Science.gov (United States)

    Qureshi, Muhammad Ahsan; Noor, Rafidah Md; Shamim, Azra; Shamshirband, Shahaboddin; Raymond Choo, Kim-Kwang

    2016-01-01

    Radio propagation models (RPMs) are generally employed in Vehicular Ad Hoc Networks (VANETs) to predict path loss in multiple operating environments (e.g. modern road infrastructure such as flyovers, underpasses and road tunnels). For example, different RPMs have been developed to predict propagation behaviour in road tunnels. However, most existing RPMs for road tunnels are computationally complex and are based on field measurements in frequency band not suitable for VANET deployment. Furthermore, in tunnel applications, consequences of moving radio obstacles, such as large buses and delivery trucks, are generally not considered in existing RPMs. This paper proposes a computationally inexpensive RPM with minimal set of parameters to predict path loss in an acceptable range for road tunnels. The proposed RPM utilizes geometric properties of the tunnel, such as height and width along with the distance between sender and receiver, to predict the path loss. The proposed RPM also considers the additional attenuation caused by the moving radio obstacles in road tunnels, while requiring a negligible overhead in terms of computational complexity. To demonstrate the utility of our proposed RPM, we conduct a comparative summary and evaluate its performance. Specifically, an extensive data gathering campaign is carried out in order to evaluate the proposed RPM. The field measurements use the 5 GHz frequency band, which is suitable for vehicular communication. The results demonstrate that a close match exists between the predicted values and measured values of path loss. In particular, an average accuracy of 94% is found with R2 = 0.86.

  2. Pulsed radio frequency interference effects on data communications via satellite transponder

    Science.gov (United States)

    Weinberg, A.; Hong, Y.

    1979-01-01

    Power-limited communication links may be susceptible to significant degradation if intentional or unintentional pulsed high level radio frequency interference (RFI) is present. Pulsed RFI is, in fact, of current interest to NASA in studies relating to its Tracking and Data Relay Satellite System (TDRSS). The present paper examines the impact of pulsed RFI on the error probability performance of a power-limited satellite communication link: the assumed modulation scheme is PN coded binary PSK. The composite effects of thermal noise, pulsed CW and pulsed Gaussian noise are analyzed, where RFI arrivals are assumed to follow Poisson statistics. Under the assumption that the satellite repeater is ideal and that integrate and dump filtering is employed at the ground receiver, an exact error probability expression and associated approximations are derived. Computed results are generated using an arbitrarily specified RFI model.

  3. Characterization of Impulse Radio Intrabody Communication System for Wireless Body Area Networks.

    Science.gov (United States)

    Cai, Zibo; Seyedi, MirHojjat; Zhang, Weiwei; Rivet, Francois; Lai, Daniel T H

    2017-01-01

    Intrabody communication (IBC) is a promising data communication technique for body area networks. This short-distance communication approach uses human body tissue as the medium of signal propagation. IBC is defined as one of the physical layers for the new IEEE 802.15.6 or wireless body area network (WBAN) standard, which can provide a suitable data rate for real-time physiological data communication while consuming lower power compared to that of radio-frequency protocols such as Bluetooth. In this paper, impulse radio (IR) IBC (IR-IBC) is examined using a field-programmable gate array (FPGA) implementation of an IBC system. A carrier-free pulse position modulation (PPM) scheme is implemented using an IBC transmitter in an FPGA board. PPM is a modulation technique that uses time-based pulse characteristics to encode data based on IR concepts. The transmission performance of the scheme was evaluated through signal propagation measurements of the human arm using 4- and 8-PPM transmitters, respectively. 4 or 8 is the number of symbols during modulations. It was found that the received signal-to-noise ratio (SNR) decreases approximately 8.0 dB for a range of arm distances (5-50 cm) between the transmitter and receiver electrodes with constant noise power and various signal amplitudes. The SNR for the 4-PPM scheme is approximately 2 dB higher than that for the 8-PPM one. In addition, the bit error rate (BER) is theoretically analyzed for the human body channel with additive white Gaussian noise. The 4- and 8-PPM IBC systems have average BER values of 10(-5) and 10(-10), respectively. The results indicate the superiority of the 8-PPM scheme compared to the 4-PPM one when implementing the IBC system. The performance evaluation of the proposed IBC system will improve further IBC transceiver design.

  4. Chaotic communication in radio-over-fiber transmission based on optoelectronic feedback semiconductor lasers.

    Science.gov (United States)

    Lin, Fan-Yi; Tsai, Meng-Chiao

    2007-01-22

    Performance of chaotic communication in radio-over-fiber (ROF) transmission based on optoelectronic feedback semiconductor lasers is studied numerically. The chaotic carrier is generated by optoelectronic feedback semiconductor lasers, where chaotic communication is realized by synchronizing a receiver laser with a transmitter laser. Transmission quality of different message encoding schemes, including additive chaos modulation (ACM) and on-off shift keying (OOSK), are investigated and compared. In this study, the dispersion and nonlinearity effects in the fiber transmission module and the amplified spontaneous emission noise from the optical amplifiers are considered. In the wireless channel, effects of additive white Gaussian noise, multipath, and path loss are included. To quantitatively study the performance of this chaotic communication system in the ROF transmission, bit-error-rates (BER) of different transmission lengths, message bit-rates, and signal-to-noise ratios are studied. The optimal launched power and message strength that minimize the BER while assuring effective communication security are discussed. While the ACM scheme is shown to perform better in a fiber only configuration, the OOSK scheme shows better immunity to the random effects and waveform distortions presented in the wireless channel.

  5. Radios in the Classroom: Curriculum Integration and Communication Skills. ERIC Digest.

    Science.gov (United States)

    Ninno, Anton

    Teachers have explored the use of radio in the classroom almost since radio technology entered into the mainstream of society, yet radio remains a relatively unused mode of instruction. This Digest describes several radio applications and summarizes various radio activities to assist teachers in integrating technology into the curriculum.…

  6. Experimental evaluation of a radio-on-FSO communication system for multiple RF signal transmission

    Science.gov (United States)

    Kazaura, Kamugisha; Dat, Pham; Bekkali, Abdelmoula; Shah, Alam; Suzuki, Toshiji; Wakamori, Kazuhiko; Matsumoto, Mitsuji; Nakamura, Takuya; Takahashi, Koichi; Higashino, Takeshi; Aburakawa, Yuji; Tsukamoto, Katsutoshi; Komaki, Shozo

    2009-02-01

    In this paper we present the design concept plus experimental results and evaluation of a newly developed advanced DWDM Radio-on-Free-Space Optical (RoFSO) communication system capable of simultaneous transmission of multiple RF signals. The RoFSO system is evaluated based on the performance metric parameters defined for the various RF signals comprising of different wireless services including terrestrial digital broadcasting signals, cellular 3GPP W-CDMA signals, IEEE 802.11 WLAN based signals etc being transmitted over the RoFSO link. The performance metric parameters being considered include standard optical received power, CNR and BER characteristics, W-CDMA signal transmission metric parameters like Adjacent Channel Leakage Ratio (ACLR) and Error Vector Magnitude (EVM), modulation error ratio (MER) for digital terrestrial television broadcasting signals as well as spectrum mask and EVM for IEEE 802.11 Wireless LAN signal transmission.

  7. A paid radio advertising campaign to promote parent-child communication about alcohol.

    Science.gov (United States)

    Surkan, Pamela J; Dejong, William; Herr-Zaya, Kathleen M; Rodriguez-Howard, Mayra; Fay, Kevin

    2003-01-01

    This study assessed the impact of a paid radio commercial designed to promote parent-child communication about alcohol use and sponsored by the Bureau of Substance Abuse Services, Massachusetts Department of Public Health. A random-digit-dial telephone survey of parents or guardians of children ages 10-17 years was conducted after a four-week advertising flight. Respondents with unassisted recall of the commercial more often disagreed that parent-child discussion is useful only if children have begun to experiment with alcohol, and more often reported having three or more parent-child discussions about alcohol compared to those who did not recall the commercial. Findings suggest the potential benefit of paid media campaigns to encourage parents to talk with their children about alcohol.

  8. Concurrent communication and sensing in cognitive radio devices: challenges and an enabling solution

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Alrabadi, Osama; Tatomirescu, Alexandru

    2014-01-01

    Cognitive Radios (CRs) need to continuously monitor the availability of unoccupied spectrum. Prior work on spectrum sensing mainly focused on time-slotted schemes where sensing and communication take place on different time periods in the same frequency. This however leads to a) limited CR...... throughput as data transmissions need to be interrupted for the sensing task, and b) unreliable detection performance since sensing happens in specific confined time durations. The paper describes the basic design challenges and hardware requirements that restrain CRs from simultaneously and continuously...... sensing the spectrum while transmitting in the same frequency band. The paper then describes a novel approach based on spatial filtering that promises to empower CRs with concurrent transmission and sensing capabilities. The idea is to equip the CR with redundant transmit antennas for forming an adaptive...

  9. Transmit-reference methods in software defined radio platforms for communication in harsh propagation environments and systems thereof

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, Farid; Nekoogar, Faranak

    2017-01-03

    A method for adaptive Radio Frequency (RF) jamming according to one embodiment includes dynamically monitoring a RF spectrum; detecting any undesired signals in real time from the RF spectrum; and sending a directional countermeasure signal to jam the undesired signals. A method for adaptive Radio Frequency (RF) communications according to another embodiment includes transmitting a data pulse in a RF spectrum; and transmitting a reference pulse separated by a predetermined period of time from the data pulse; wherein the data pulse is modulated with data, wherein the reference pulse is unmodulated. A method for adaptive Radio Frequency (RF) communications according to yet another embodiment includes receiving a data pulse in a RF spectrum; and receiving a reference pulse separated in time from the data pulse, wherein the data pulse is modulated with data, wherein the reference pulse is unmodulated; and demodulating the pulses.

  10. United States Army Land Mobile Radio Communication System: Impacts of Information Assurance on Commercial Off-the-Shelf Systems

    Science.gov (United States)

    2010-06-01

    Manager; Program Manager PSTN Public Switched Telephone Network RF Radio Frequency SME Subject Matter Expert SBU Sensitive But Unclassified TDMA...Non-tactical LMRs likely to be used for communicating Sensitive But Unclassified ( SBU ) information shall meet medium or basic robustness…50

  11. Community Participation, Cultural Discourse, and Health Education Projects in Developing Areas: The Case of the Radio Communication Project in Nepal

    Science.gov (United States)

    Linn, J. Gary

    2008-01-01

    In this article, the author comments on the article by Dutta and Basnyat (see EJ802883) that provides an insightful and comprehensive critique of a United States Agency for International Development (USAID) entertainment-education program, The Radio Communication Program (RCP) in Nepal, which has been reported to be highly participatory. Despite…

  12. Radio Wave Propagation for Communication on and around Mars. Part 1; Highlights: Propagation Through Mars Environment

    Science.gov (United States)

    Ho, Christian; Golshan, Nasser

    1999-01-01

    We recommend to use the dayside Martian ionosphere as a reflector for global communication, because the dayside ionosphere has stable density peak and usable critic frequency. This is very crucial for the future Mars ground to around communication. The dayside ionosphere has been well modeled as a Chapman layer. We suggest to perform the Martian nightside ionospheric modeling study. Because the nightside ionosphere has very little measurements available, we propose to drop a digital ionosond instrument into the Mars surface for data collection. Even though the Martian tropospheric radio refractivity has small value, it still can cause the ray bending and multipath effects. We recommend to perform an accurate calculation on excess phase and group delays (range and time delays). Other effects, such as range rate errors, appearance angle deviation, defocusing loss on Mars, etc. are also needed to be estimated. Ice depolarization effects due to Martian clouds on radio waves is unknown yet, which is expected to be small, because lower optical depth and thinner layer of cloud: Total Martian atmospheric gaseous attenuation is expected to be less than 1 dB on microwaves band, because the Martian atmosphere has very low concentration in uncondensed H2O and O2. An accurate calculation for zenith opacity requires the information about scale heights of H2O and O2 distribution. An accurate water vapor altitude profile at Mars is not available yet. Under the normal condition, CO2 and N2 gases do not have electric or magnetic dipoles and do not absorb electromagnetic energy from the waves. However, they may generate the dipoles through a collision and interact with waves under a high density condition and absorb electromagnetic waves in the infrared and visible band. Dust storm is most dominant factor to the radio wave attenuation. Large Martian dust storm can cause at least 3 dB or higher loss to Ka band wave. For a normal dust storm, the attenuation is about 1 dB. The

  13. Communication: Theoretical study of HfF+ cation to search for the T,P-odd interactions

    Science.gov (United States)

    Skripnikov, L. V.

    2017-07-01

    The combined all-electron and two-step approach is applied to calculate the molecular parameters which are required to interpret the ongoing experiment to search for the effects of manifestation of the T,P-odd fundamental interactions in the HfF+ cation by Loh et al. [Science 342, 1220 (2013)] and Ni et al. [J. Mol. Spectrosc. 300, 12 (2014)]. The effective electric field that is required to interpret the experiment in terms of the electron electric dipole moment is found to be 22.5 GV/cm. In the work of Pospelov and Ritz [Phys. Rev. D 89, 056006 (2014)], it was shown that another source of the T,P-odd interaction, the scalar-pseudoscalar nucleus-electron interaction with the dimensionless strength constant kT,P can dominate over the direct contribution from the electron electric dipole moment within the standard model and some of its extensions. Therefore, for the comprehensive and correct interpretation of the HfF+ experiment, one should also know the molecular parameter WT,P, the value of which is reported here to be 20.1 kHz.

  14. Opportunistic Communication (Cognitive Radio over Primary Discarded Subchannels by Applying a Double Power Distribution

    Directory of Open Access Journals (Sweden)

    G. A. Medina-Acosta

    2010-01-01

    Full Text Available This paper proposes the establishment of a simultaneous cognitive radio communication based on a subdistribution of power made over unselected subchannels which were discarded by the primary user through an initial optimal power allotment. The aim of this work is to show the possibility of introducing an opportunistic communication into a licensed transmission where the total power constraint is shared. The analysis of the proposed transmission scheme was performed by considering 128 and 2048 independent subchannels affected by Rayleigh fading, over 10,000 channel realizations, and three different signal-to-noise ratios (8 dB, 16 dB, and 24 dB. From the system evaluation it was possible to find the optimal power allotment for the primary user, the subdistribution of power for the secondary user, as well as the attenuation and the capacity per subchannel for every channel realization. Moreover, the PDF and CDF of the total obtained capacities, as well as the generation of empirical capacity regions, were estimated as complementary results.

  15. Electrical Characterization of Metal-Insulator-Metal Capacitors with Atomic-Layer-Deposited HfO2 Dielectrics for Radio Frequency Integrated Circuit Application

    Institute of Scientific and Technical Information of China (English)

    HUANG Yu-Jian; HUANG Yue; DING Shi-Jin; ZHANG Wei; LIU Ran

    2007-01-01

    Metal-insulator-metal (MIM) capacitors with atomic-layer-deposited HfO2 dielectric and TaN electrodes are investigated for rf integrated circuit applications. For 12nm HfO2, the fabricated capacitor exhibits a high capacitance density of 15.5fF/μm2 at 100kHz, a small leakage current density of 6.4 × 10-9 A/cm2 at 1.8 V and 125℃, a breakdown electric field of 2.6 MV/cm as well as voltage coefficients of capacitance (VCCs) of 2110ppm/V2 and -824 ppm/V at 100kHz. Further, it is deduced that the conduction mechanism in the high field range is dominated by the Poole-Frenkel emission, and the conduction mechanism in the low field range is possibly related to trap-assisted tunnelling. Finally, comparison of various HfO2 MIM capacitors is present,suggesting that the present MIM capacitor is a promising candidate for future rf integrated circuit application.

  16. Collective Review: Catalyzing Sustainable Social Change through Public Communication, Radio for Development, and Participatory Monitoring and Evaluation

    Directory of Open Access Journals (Sweden)

    Levi Zeleza Manda

    2014-07-01

    Full Text Available This article reviews three recent books by four authors (two single, one joint from Australia and Africa. The three books are related in that they all discuss the need to acknowledge the role of dialogic communication and popular participation as catalysts for sustainable social development in the developing world. Specifically, "Public Relations, Activism and Social Change" proposes that public relations (PR needs to transform itself into public communication (PC, where people are made to make decisions based on dialogue and the correctness of the information rather than out of manipulative propaganda. "People's Radio" argues that radio can lead to tangible and long-lasting social change if it engages the primary beneficiaries in the planning, production presentation of the programs and management of (community radio stations. "Evaluating Communication for Development" argues that through indicators defined by the local people themselves, evaluators can find evidence of social change brought about by communication for development activities. The book suggests that to be effective, monitoring and evaluation of communication for development ought to be participatory and use qualitative data collection tools such as focus groups, in-depth interviews, and most significant change (MSC evaluations. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs140383

  17. Cryogenically cooled low-noise amplifier for radio-astronomical observations and centimeter-wave deep-space communications systems

    Science.gov (United States)

    Vdovin, V. F.; Grachev, V. G.; Dryagin, S. Yu.; Eliseev, A. I.; Kamaletdinov, R. K.; Korotaev, D. V.; Lesnov, I. V.; Mansfeld, M. A.; Pevzner, E. L.; Perminov, V. G.; Pilipenko, A. M.; Sapozhnikov, B. D.; Saurin, V. P.

    2016-01-01

    We report a design solution for a highly reliable, low-noise and extremely efficient cryogenically cooled transmit/receive unit for a large antenna system meant for radio-astronomical observations and deep-space communications in the X band. We describe our design solution and the results of a series of laboratory and antenna tests carried out in order to investigate the properties of the cryogenically cooled low-noise amplifier developed. The transmit/receive unit designed for deep-space communications (Mars missions, radio observatories located at Lagrangian point L2, etc.) was used in practice for communication with live satellites including "Radioastron" observatory, which moves in a highly elliptical orbit.

  18. Software-Defined Radio Global System for Mobile Communications Transmitter Development for Heterogeneous Network Vulnerability Testing

    Science.gov (United States)

    2013-12-01

    48  3.  Results .................................................................................................48  a.  GNU Radio ...56  b.  GNU Radio Collection...by GNU Radio of the baseband signal created by the GSM transmitter code mimicking the GSM BTS BCH prior to USRP transmission. The blue signal shows

  19. Talk radio as the soundtrack of our lives: Participatory HIV/AIDS communication, public self-expression and Positive Talk.

    Science.gov (United States)

    Burger, Mariekie

    2015-01-01

    Despite the many HIV/AIDS communication initiatives, combined with support and infrastructural support in South Africa, risky behaviour associated with the spread of the epidemic is increasing amongst many groups. This calls for a re-evaluation of endeavours aimed at curbing the spread of the epidemic. This article is only concerned with the communicational aspects of the epidemic, but does not negate the interaction of these with other measures taken to address the epidemic. As is the case with most health communication initiatives, HIV/AIDS communication initiatives have evolved to favour the participatory approach above one-directional transmission of information to the public. The participatory approach rests on the assumption that an HIV/AIDS communication initiative stands the best chance of resulting in behaviour change if members of the target community participate in the communication initiative. The assumption is that as many people as possible should be involved in the maximum number of phases of the communicative initiative (such as initial research, planning, implementation and evaluation of the project). Some research has recently started to explore new forms of community participation, including inviting community participation through, for example, internet-based platforms such as social media, and mobile phone platforms such as WhatsApp and BBM. However, the reality broadcast genre--more specifically, talk radio--has been neglected, as only a few research investigations focused on talk radio and most of these are not exclusively about HIV/AIDS communication but focus on other health topics. From a participatory communication perspective, two sets of critique against the existing HIV/AIDS communication projects hold water: firstly, they do not make the maximum use of participatory communication principles and, secondly, they are externally initiated projects and emanate from outside the target community. To address both of these concerns, this

  20. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs

    Science.gov (United States)

    Sayyed, Ali; Medeiros de Araújo, Gustavo; Bodanese, João Paulo; Buss Becker, Leandro

    2015-01-01

    The use of mobile nodes to collect data in a Wireless Sensor Network (WSN) has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs) as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA), which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node. PMID:26389911

  1. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs.

    Science.gov (United States)

    Sayyed, Ali; de Araújo, Gustavo Medeiros; Bodanese, João Paulo; Becker, Leandro Buss

    2015-09-16

    The use of mobile nodes to collect data in a Wireless Sensor Network (WSN) has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs) as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA), which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node.

  2. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs

    Directory of Open Access Journals (Sweden)

    Ali Sayyed

    2015-09-01

    Full Text Available The use of mobile nodes to collect data in a Wireless Sensor Network (WSN has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA, which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node.

  3. Socio-Economic Aspects of National Communication Systems: III. Radio Broadcasting in Venezuela. Communication and Society, 12.

    Science.gov (United States)

    Capriles, Oswaldo; And Others

    The third in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Venezuela. An overview of radio broadcasting in Venezuela describes various aspects and provides…

  4. Redes de participación e intercambios en la radio pública: los podcasting Networks of Participation and Communicative Interchanges in Public Radio: Podcasting

    Directory of Open Access Journals (Sweden)

    Carmen Salgado Santamaría

    2009-10-01

    Full Text Available El desarrollo de los podcasting, como sistema añadido de la ciberradio, impulsa a las redes de participación e intercambios comunicativos de interés social, que exhiben numerosas ventajas frente a las prácticas radiofónicas conocidas. La difusión que la radio pública realiza de los podcasts, la colocan en el actual proceso de convergencia tecnológica, y la sitúan en una sociedad de la información y del conocimiento, capaz de ofrecer diferentes servicios al alcance de todos los ciudadanos. Sólo la introducción de nuevos contenidos y servicios que aporten valor añadido a los existentes y satisfagan las necesidades de sus usuarios, procurarán la rentabilidad de este sistema. The development of podcasting as an additional system of cyberradio stimulates the appearance of networks of participation and communicative interchanges of social interest, and has numerous advantages over conventional radio practices. The spreading of podcasts through public radio situates it within the process of technological convergence and in an Information and Knowledge society which is able to offer different services within reach of all citizens. Only the introduction of new contents and services that contribute added value to the existing ones and satisfy the needs of users will make this system profitable.

  5. Conversion of a 30-m former satellite communications antenna to a radio telescope

    Science.gov (United States)

    Deboer, David R.; Steffes, Paul G.; Glowacki, John M.

    1998-05-01

    A class of large satellite communication antennas built in the mid-1970's comprise a potential set of large antennas available for use by radio astronomers upon upgrade. With the advent of low noise technology these facilities have been superseded in the communications industry by smaller, more manageable facilities. Although many have sat idle and decaying over the intervening years, these facilities remain a potential resource for research and education. A pair of such dishes has been acquired by Georgia Tech and one of the 30 meter antennas has been completely mechanically and electrically stripped and new mechanical, control, RF, and electrical systems installed. The antenna is now driven by four continuous-speed vector-controlled three-phase AC induction motors with variable frequency vector motor drives. Sixteen bit resolution optical absolute position encoders on each axis provide telescope pointing data. Sixteen bit resolution optical absolute position encoders on each axis provide telescope pointing data. A programmable logic controller provides interlock monitoring and control. The antenna is controllable both manually via a portable remote control unit and via a Pentium PC running control software on a real-time UNIX-based platform. The manual unit allows limited control at two user-selectable speeds while computer control allows full tracking capability with accuracies of better than 0.3 arcminutes. The facility can be remotely controlled via the internet, although currently only a dedicated line is used. The antenna has been refitted with an ultra-broadband feed system capable of operating from 1-7 GHz.

  6. Control and Non-Payload Communications (CNPC) Prototype Radio - Generation 2 Security Flight Test Report

    Science.gov (United States)

    Iannicca, Dennis C.; Ishac, Joseph A.; Shalkhauser, Kurt A.

    2015-01-01

    NASA Glenn Research Center (GRC), in cooperation with Rockwell Collins, is working to develop a prototype Control and Non-Payload Communications (CNPC) radio platform as part of NASA Integrated Systems Research Program's (ISRP) Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) project. A primary focus of the project is to work with the Federal Aviation Administration (FAA) and industry standards bodies to build and demonstrate a safe, secure, and efficient CNPC architecture that can be used by industry to evaluate the feasibility of deploying a system using these technologies in an operational capacity. GRC has been working in conjunction with these groups to assess threats, identify security requirements, and to develop a system of standards-based security controls that can be applied to the GRC prototype CNPC architecture as a demonstration platform. The proposed security controls were integrated into the GRC flight test system aboard our S-3B Viking surrogate aircraft and several network tests were conducted during a flight on November 15th, 2014 to determine whether the controls were working properly within the flight environment. The flight test was also the first to integrate Robust Header Compression (ROHC) as a means of reducing the additional overhead introduced by the security controls and Mobile IPv6. The effort demonstrated the complete end-to-end secure CNPC link in a relevant flight environment.

  7. Radio Frequency Identification (RFID) and communication technologies for solid waste bin and truck monitoring system.

    Science.gov (United States)

    Hannan, M A; Arebey, Maher; Begum, R A; Basri, Hassan

    2011-12-01

    This paper deals with a system of integration of Radio Frequency Identification (RFID) and communication technologies for solid waste bin and truck monitoring system. RFID, GPS, GPRS and GIS along with camera technologies have been integrated and developed the bin and truck intelligent monitoring system. A new kind of integrated theoretical framework, hardware architecture and interface algorithm has been introduced between the technologies for the successful implementation of the proposed system. In this system, bin and truck database have been developed such a way that the information of bin and truck ID, date and time of waste collection, bin status, amount of waste and bin and truck GPS coordinates etc. are complied and stored for monitoring and management activities. The results showed that the real-time image processing, histogram analysis, waste estimation and other bin information have been displayed in the GUI of the monitoring system. The real-time test and experimental results showed that the performance of the developed system was stable and satisfied the monitoring system with high practicability and validity.

  8. Comparative Study of Optical and Radio-Frequency Communication Systems for a Deep-Space Mission

    Science.gov (United States)

    Hemmati, H.; Wilson, K.; Sue, M. K.; Harcke, L. J.; Wilhelm, M.; Chen, C.-C.; Lesh, J.; Feria, Y.; Rascoe, D.; Lansing, F.

    1997-01-01

    We have performed a study on telecommunication systems for a hypothetical mission to Mars. The objective of the study was to evaluate and compare the benefits that microwave-X-band (8.4 GHz) and Ka-band (32 GHz) - and optical communications technologies a afford to future missions. The telecommunication systems were required to return data after launch and in orbit at 2.7 AU with daily data volumes of 0.1, 1.0, or 10.0 Gbits (Gb). Spacecraft terminals capable of delivering each of the three data volumes were proposed and characterized in terms of mass, power consumption, size, and cost. The estimated parameters for X-band, Ka-band, and optical frequencies are compared and presented here. For all cases, the optical light terminal exhibits about 60 percent of the mass of the corresponding radio frequency (RF) subsystem. Power consumption is comparable for all three technologies at a 0.1 Gb/day data volume, but the power required at either Ka-band or optical is less than half of the X-band requirement at 10 Gb/day. These benefits can be obtained only with a suitable investment in reception facilities for Ka-band or optical frequencies.

  9. Energy Efficiency in MIMO Underlay and Overlay Device-to-Device Communications and Cognitive Radio Systems

    Science.gov (United States)

    Zappone, Alessio; Matthiesen, Bho; Jorswieck, Eduard Axel

    2017-02-01

    This paper addresses the problem of resource allocation for systems in which a primary and a secondary link share the available spectrum by an underlay or overlay approach. After observing that such a scenario models both cognitive radio and D2D communications, we formulate the problem as the maximization of the secondary energy efficiency subject to a minimum rate requirement for the primary user. This leads to challenging non-convex, fractional problems. In the underlay scenario, we obtain the global solution by means of a suitable reformulation. In the overlay scenario, two algorithms are proposed. The first one yields a resource allocation fulfilling the first-order optimality conditions of the resource allocation problem, by solving a sequence of easier fractional problems. The second one enjoys a weaker optimality claim, but an even lower computational complexity. Numerical results demonstrate the merits of the proposed algorithms both in terms of energy-efficient performance and complexity, also showing that the two proposed algorithms for the overlay scenario perform very similarly, despite the different complexity.

  10. Jitter-Robust Orthogonal Hermite Pulses for Ultra-Wideband Impulse Radio Communications

    Directory of Open Access Journals (Sweden)

    Ryuji Kohno

    2005-03-01

    Full Text Available The design of a class of jitter-robust, Hermite polynomial-based, orthogonal pulses for ultra-wideband impulse radio (UWB-IR communications systems is presented. A unified and exact closed-form expression of the auto- and cross-correlation functions of Hermite pulses is provided. Under the assumption that jitter values are sufficiently smaller than pulse widths, this formula is used to decompose jitter-shifted pulses over an orthonormal basis of the Hermite space. For any given jitter probability density function (pdf, the decomposition yields an equivalent distribution of N-by-N matrices which simplifies the convolutional jitter channel model onto a multiplicative matrix model. The design of jitter-robust orthogonal pulses is then transformed into a generalized eigendecomposition problem whose solution is obtained with a Jacobi-like simultaneous diagonalization algorithm applied over a subset of samples of the channel matrix distribution. Examples of the waveforms obtained with the proposed design and their improved auto- and cross-correlation functions are given. Simulation results are presented, which demonstrate the superior performance of a pulse-shape modulated (PSM- UWB-IR system using the proposed pulses, over the same system using conventional orthogonal Hermite pulses, in jitter channels with additive white Gaussian noise (AWGN.

  11. A staged model of communication effects: evidence from an entertainment-education radio soap opera in Tanzania.

    Science.gov (United States)

    Vaughan, P W; Rogers, E M

    2000-01-01

    The authors draw on (1) the hierarchy-of-effects (HOE) model, (2) the stages-of-change (SOC) model, (3) social learning theory (SLT), and (4) the diffusion of innovations (DOI) to synthesize a staged model through which communication messages have effects on individual behavior change by stimulating (1) involvement with media characters and role modeling of their actions, and (2) interpersonal communication. Data from a field experiment in Tanzania on the effects of an entertainment-education radio soap opera, Twende na Wakati (Let's Go With the Times), on the adoption of family planning, are analyzed in light of a six-staged model of communication effects. It is found that (1) the model provides a useful framework for understanding the effects of an entertainment-education program, and (2) the radio soap opera promoted progress through the stages for family planning adoption in the treatment area in three of the four years of broadcast, and in the comparison area after broadcasts of the radio program began there.

  12. Enhanced UWB Radio Channel Model for Short-Range Communication Scenarios Including User Dynamics

    DEFF Research Database (Denmark)

    Kovacs, Istvan Zsolt; Nguyen, Tuan Hung; Eggers, Patrick Claus F.

    2005-01-01

    In this paper we propose a SISO UWB radio channel model for short-range radio link scenarios between a fixed device and a dynamic user hand-held device. The channel model is derived based on novel experimental UWB radio propagation investigations carried out in typical indoor PAN scenarios...... including realistic device and user terminal antenna configurations. The radio channel measurements have been performed in the lower UWB frequency band of 3GHz to 5GHz with a 2x4 MIMO antenna configuration. Several environments, user scenarios and two types of user terminals have been used. The developed...

  13. Control and Non-Payload Communications (CNPC) Prototype Radio - Generation 2 Security Architecture Lab Test Report

    Science.gov (United States)

    Iannicca, Dennis C.; McKim, James H.; Stewart, David H.; Thadhani, Suresh K.; Young, Daniel P.

    2015-01-01

    NASA Glenn Research Center, in cooperation with Rockwell Collins, is working to develop a prototype Control and Non-Payload Communications (CNPC) radio platform as part of NASA Integrated Systems Research Program's (ISRP) Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) project. A primary focus of the project is to work with the FAA and industry standards bodies to build and demonstrate a safe, secure, and efficient CNPC architecture that can be used by industry to evaluate the feasibility of deploying a system using these technologies in an operational capacity. GRC has been working in conjunction with these groups to assess threats, identify security requirements, and to develop a system of standards-based security controls that can be applied to the current GRC prototype CNPC architecture as a demonstration platform. The security controls were integrated into a lab test bed mock-up of the Mobile IPv6 architecture currently being used for NASA flight testing, and a series of network tests were conducted to evaluate the security overhead of the controls compared to the baseline CNPC link without any security. The aim of testing was to evaluate the performance impact of the additional security control overhead when added to the Mobile IPv6 architecture in various modes of operation. The statistics collected included packet captures at points along the path to gauge packet size as the sample data traversed the CNPC network, round trip latency, jitter, and throughput. The effort involved a series of tests of the baseline link, a link with Robust Header Compression (ROHC) and without security controls, a link with security controls and without ROHC, and finally a link with both ROHC and security controls enabled. The effort demonstrated that ROHC is both desirable and necessary to offset the additional expected overhead of applying security controls to the CNPC link.

  14. Socio-Economic Aspects of National Communication Systems. I. Radio Broadcasting in Austria. Communication and Society, 10.

    Science.gov (United States)

    Signitzer, Benno; Luger, Kurt

    The first in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Austria. It deals with the cultural implications of broadcasting structures and their ownership…

  15. Socio-Economic Aspects of National Communication Systems: II. Radio Broadcasting in Czechoslovakia. Communication and Society, 11.

    Science.gov (United States)

    Bunzlova, Alice; Slovak, Leopold

    The second in a series that examines the role of radio broadcasting in the process of socioeconomic and cultural change in three countries with different types of broadcasting organization--Austria, Czechoslovakia, and Venezuela--this volume focuses on Czechoslovakia. It deals with the cultural implications of broadcasting structures and their…

  16. MF-CRA: Multi-Function Cognitive Radio Architecture for Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — EpiSys Science, Inc. and University of Arizona propose to develop, implement, and demonstrate Multi-Function Cognitive Radio Architecture (MF-CRA) for Space...

  17. The Deep Space Network: A Radio Communications Instrument for Deep Space Exploration

    Science.gov (United States)

    Renzetti, N. A.; Stelzried, C. T.; Noreen, G. K.; Slobin, S. D.; Petty, S. M.; Trowbridge, D. L.; Donnelly, H.; Kinman, P. W.; Armstrong, J. W.; Burow, N. A.

    1983-01-01

    The primary purpose of the Deep Space Network (DSN) is to serve as a communications instrument for deep space exploration, providing communications between the spacecraft and the ground facilities. The uplink communications channel provides instructions or commands to the spacecraft. The downlink communications channel provides command verification and spacecraft engineering and science instrument payload data.

  18. UAS in the NAS Project: Large-Scale Communication Architecture Simulations with NASA GRC Gen5 Radio Model

    Science.gov (United States)

    Kubat, Gregory

    2016-01-01

    This report provides a description and performance characterization of the large-scale, Relay architecture, UAS communications simulation capability developed for the NASA GRC, UAS in the NAS Project. The system uses a validated model of the GRC Gen5 CNPC, Flight-Test Radio model. Contained in the report is a description of the simulation system and its model components, recent changes made to the system to improve performance, descriptions and objectives of sample simulations used for test and verification, and a sampling and observations of results and performance data.

  19. L'arrivée du WiFi, technologie de télécommunication radio

    OpenAIRE

    Dumé, Bel; Ubéda, Stéphane

    2012-01-01

    National audience; La technologie radio 802.11, désormais bien connue sous le nom de Wi-Fi, est développée à la fin des années 1990, mais sa mise en oeuvre est assez compliquée et il faudra attendre les années 2002-2003 pour que les vraies cartes Wi-Fi arrivent sur le marché et ouvrent le champ des applications d'objets mobiles communicants.

  20. RFID UHF i HF w bibliotekach

    Directory of Open Access Journals (Sweden)

    Gładysz Bartłomiej

    2015-06-01

    Full Text Available The potential of the innovative Radio Frequency Identification (RFID technology to be applied for support, acceleration and automation of the circulation process of library collection is presented. Technology basics, and hardware and software components are described. Two different radio standards used in libraries are compared. The goal is to present the potential of RFID technology for libraries, to highlight the differences and to build a basis for further consideration of UHF and HF alternatives.

  1. Subjective voice quality, communicative ability and swallowing after definitive radio(chemo)therapy, laryngectomy plus radio(chemo)therapy, or organ conservation surgery plus radio(chemo)therapy for laryngeal and hypopharyngeal cancer.

    Science.gov (United States)

    Szuecs, Marcella; Kuhnt, Thomas; Punke, Christoph; Witt, Gabriele; Klautke, Gunther; Kramp, Burkhard; Hildebrandt, Guido

    2015-01-01

    This retrospective analysis focusses on the impact of therapy on perceived long-term post-cancer treatment function. A validated questionnaire including items and components for the assessment of communicative ability, quality of voice and swallowing was sent to 129 patients. All patients were treated between 1998 and 2007. A total of 76 patients (58.9%) with carcinoma of the larynx or hypopharynx replied to the questionnaire. Data was evaluated retrospectively. Therapy delivered was definitive radio(chemo)therapy (defchRT/RT) (21/76, 28%), laryngectomy + radio(chemo)therapy (LE + chRT/RT) (28/76, 37%), or larynx conservation surgery + radio(chemo)therapy (LCS + chRT/RT) (27/76, 36%). Radiotherapy was administered using 2D- or 3D-conformal planning. The most common concomitant chemotherapy delivered was cisplatin + 5FU. For statistical analyses of the components, averages were calculated and tested using the Kruskal-Wallis test and the U-test of Mann and Whitney. Differences were assessed by the Monte Carlo method or Fisher's exact test. The single item rates were compared with Fisher's exact test. Mean follow-up was 56.7 months (range, 8-130 months). After defchRT/RT, patients trended towards more substantial-strong hoarseness compared with LCS + chRT/RT (P = 0.2). After LE, patients were dissatisfied with their artificial larynx/electrolarynx and the tone of their voice (P = 0.3, P = 0.07) and communicative ability (P = 0.005, P = 0.008) compared with those treated with defchRT/RT and LCS + chRT/RT, respectively. Dysphagia and additional percutaneous endoscopic gastrostomy (PEG) feeding were more frequent after defchRT/RT in comparison with the other two groups (P < 0.05). Voice quality and communicative ability were slightly worse after defchRT/RT and LE + chRT/RT, but satisfying with all treatment modalities. Further development of the therapy approach is necessary to reduce long-term side effects, with measures of post-treatment function as important endpoints.

  2. The Radio Communication Project in Nepal: A Culture-Centered Approach to Participation

    Science.gov (United States)

    Dutta, Mohan Jyoti; Basnyat, Iccha

    2008-01-01

    Considerable research has been conducted on the topic of entertainment-education (EE), the method of using entertainment platforms such as popular music, radio, and television programming to diffuse information, attitudes, and behaviors via role modeling. A significant portion of the recently published EE literature has used the case of the Radio…

  3. 75 FR 46854 - Amendment of the Commission's Rules Regarding Amateur Radio Service Communications During...

    Science.gov (United States)

    2010-08-04

    ... the NPRM, public safety agencies and other emergency first responder entities voiced general support... radio. This integrative activity is essential to allow for a practiced response on the part of the first responder community in the event of an emergency. Because some of those drills and exercises include...

  4. Army Communicator. Volume 31, Number 2, Spring 2006

    Science.gov (United States)

    2006-01-01

    see Army Commu- nicator article titled HF Combat Net Radio Lesson Learned Again, by David M. Fiedler , Spring 2004). Integrating more communications...year- round,” said Drew. According to Fred Porzio, project leader for this effort with PM DCATS’ Product Manager, Defense Wide Transmission Systems, the...Army Communicator 49 singling out Fred Porzio, the project lead for PM DWTS; Greg Parks, who designed the system for prime contractor Eaton/Powerware

  5. 电离层信道特征参数对短波通信质量影响的试验分析%Experimental Study on the Impact of Ionospheric Channel Characteristic Parameters on HF Communication Quality

    Institute of Scientific and Technical Information of China (English)

    孙凤娟; 柳文; 李铁成

    2012-01-01

    Based on the experimental data measured by the platform which combines HF communication with ionospheric oblique sounding, the communication BER and the channel characteristic parameters are extracted. The impact of the channel characteristic parameters on the communication BER is statistically analyzed. An algorithm based on empirical mode is proposed to evaluate HF communication quality, and the results show the proposed algorithm is effective in the case of DPSK modulation.%基于新乡至青岛之间融短波通信和电离层斜向探测于一体的综合试验平台实录数据,提取了通信误码率及信道特征参数,统计分析了各信道参数对通信误码率的影响,并提出了一种基于经验模式的短波通信质量评估方法,该方法在DPSK编码形式下具有很高的实效性。

  6. Considerations about the Modeling of Software Defined Radio for Mobile Communications Networks

    Directory of Open Access Journals (Sweden)

    Lucian Morgos

    2009-05-01

    Full Text Available This paper presents the contribution of theauthors regarding the modeling of a software definedradio - SDR. The digital radios are base on ADCinterfaces that convert the base band signal in a digitalformat and a DSP that accomplish the demodulationaccording to a suitable digital processing algorithm. Totest the model the authors chosen a radio signal with aWeibull distribution quadrature amplitude modulationQAM that pass through a scattering medium till the RFfront end of the SDR. The fading effect was also takeninto consideration. The results of the demodulation usingthe proposed model of SDR were compared with aRayleigh distribution. The simulation results made by thehelp of MATLAB program emphasize the effects of thequantization levels of the ADC circuit.

  7. Space Telecommunications Radio System STRS Cognitive Radio

    Science.gov (United States)

    Briones, Janette C.; Handler, Louis M.

    2013-01-01

    Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

  8. Deep Null Antennas and Their Applications to Tactical VHF Radio Communications

    Science.gov (United States)

    1989-03-01

    simulations must be carried out over less than perfect grounds. Reviev; of the Antenna Engineering Handbook . Vol. I [Ref. 6] provided the needed...means of getting the desired phase and magnitude relationships was not found, and as mentioned in the ARRL Antenna Book [Ret: 3: pp. 8-l-l], a number of...Englewood Cliffs, ::\\J, 1968. 3. American Radio Relay League, The ARRL Antenna Book, 15th ed., American Ra- dio Relay League, ~e,Yington, CT, 1988. 4

  9. Impact of the Use of Object Request Broker Middleware for Inter-Component Communications in C6416 Digital Signal Processor Based Software Communications Architecture Radio Systems

    Directory of Open Access Journals (Sweden)

    Mohamed I. Yousef

    2012-01-01

    Full Text Available Problem statement: This study presents an in-depth analysis of the performance of Software Communications Architecture (SCA component-based waveform applications in terms of inter-component communications. The main limitation with SCA, in the context of embedded systems, is the additional cost introduced by the use of Object Request Broker (ORB middleware. The ORB middleware handles the interaction between components and objects in SCA distributed environment. This interaction should be highly efficient, due to the real time nature of SCA systems and transparent to the application programmer. Approach: We can achieve high efficiency in SCA systems by enhancing the Inter-Process Communications (IPC mechanisms in Operating systems (OS micro kernels, while we achieve transparency through Interface Definition Language (IDL. Different encoding mechanisms like “External Data Representation (XDR, Network Data Representation (NDR and Common Data Representation (CDR facilitate inter-component communication transparently and efficiently”. Marshalling procedures format data from the local machine representation to common network representations. A most common encoding mechanism for Common Object Request Broker Architecture (CORBA systems is CDR representation. Measurements have been performed with ORBExpress DSP as a CORBA distribution and Open Source SCA Implementation Embedded (OSSIE for SCA implementation. In order to perform these measurements we proposed two metrics for profiling the ORB that are invocation and marshalling. In addition, we propose three elements of data types to evaluate the performance of ORB middleware that are, Basic, Array and Sequence data types. Results: The CORBA bus is really the part, which brings an overhead to the SCA radio systems. This overhead is due to method invocations that have been carried out by ORB middleware. Conclusion: Performance benchmarks of ORBExpress DSP middleware show that, although using CORBA for

  10. Antenna Technology and other Radio Frequency (RF) Communications Activities at the Glenn Research Center in Support of NASA's Exploration Vision

    Science.gov (United States)

    Miranda, Felix A.

    2007-01-01

    NASA s Vision for Space Exploration outlines a very ambitious program for the next several decades of the Space Agency endeavors. Ahead is the completion of the International Space Station (ISS); safely flight the shuttle (STS) until 2010; develop and fly the Crew Exploration Vehicle (Orion) by no later than 2014; return to the moon by no later than 2020; extend human presence across the solar system and beyond; implement a sustainable and affordable human and robotic program; develop supporting innovative technologies, knowledge and infrastructure; and promote international and commercial participation in exploration. To achieve these goals, a series of enabling technologies must be developed or matured in a timely manner. Some of these technologies are: spacecraft RF technology (e.g., high power sources and large antennas which using surface receive arrays can get up to 1 Gbps from Mars), uplink arraying (reduce reliance on large ground-based antennas and high operation costs; single point of failure; enable greater data-rates or greater effective distance; scalable, evolvable, flexible scheduling), software define radio (i.e., reconfigurable, flexible interoperability allows for in flight updates open architecture; reduces mass, power, volume), and optical communications (high capacity communications with low mass/power required; significantly increases data rates for deep space). This presentation will discuss some of the work being performed at the NASA Glenn Research Center, Cleveland, Ohio, in antenna technology as well as other on-going RF communications efforts.

  11. Secure Cooperative Spectrum Sensing via a Novel User-Classification Scheme in Cognitive Radios for Future Communication Technologies

    Directory of Open Access Journals (Sweden)

    Muhammad Usman

    2015-05-01

    Full Text Available Future communication networks would be required to deliver data on a far greater scale than is known to us today, thus mandating the maximal utilization of the available radio spectrum using cognitive radios. In this paper, we have proposed a novel cooperative spectrum sensing approach for cognitive radios. In cooperative spectrum sensing, the fusion center relies on reports of the cognitive users to make a global decision. The global decision is obtained by assigning weights to the reports received from cognitive users. Computation of such weights requires prior information of the probability of detection and the probability of false alarms, which are not readily available in real scenarios. Further, the cognitive users are divided into reliable and unreliable categories based on their weighted energy by using some empirical threshold. In this paper, we propose a method to classify the cognitive users into reliable, neutral and unreliable categories without using any pre-defined or empirically-obtained threshold. Moreover, the computation of weights does not require the detection, or false alarm probabilities, or an estimate of these probabilities. Reliable cognitive users are assigned the highest weights; neutral cognitive users are assigned medium weights (less than the reliable and higher than the unreliable cognitive users’ weights; and unreliable users are assigned the least weights. We show the performance improvement of our proposed method through simulations by comparing it with the conventional cooperative spectrum sensing scheme through different metrics, like receiver operating characteristic (ROC curve and mean square error. For clarity, we also show the effect of malicious users on detection probability and false alarm probability individually through simulations.

  12. Code-expanded radio access protocol for machine-to-machine communications

    DEFF Research Database (Denmark)

    Thomsen, Henning; Kiilerich Pratas, Nuno; Stefanovic, Cedomir

    2013-01-01

    The random access methods used for support of machine-to-machine, also referred to as Machine-Type Communications, in current cellular standards are derivatives of traditional framed slotted ALOHA and therefore do not support high user loads efficiently. We propose an approach that is motivated...... subframes and orthogonal preambles, the amount of available contention resources is drastically increased, enabling the massive support of Machine-Type Communication users that is beyond the reach of current systems....

  13. New horizons in mobile and wireless communications, v.1 radio interfaces

    CERN Document Server

    Prasad, Ramjee

    2009-01-01

    Based on cutting-edge research projects in the field, this book (part of a comprehensive 4-volume series) provides the latest details and covers the most impactful aspects of mobile, wireless, and broadband communications development. These books present key systems and enabling technologies in a clear and accessible manner, offering you a detailed roadmap the future evolution of next generation communications. Other volumes cover Networks, Services and Applications; Reconfigurability; and Ad Hoc Networks.

  14. Effects of personality on territory defence in communication networks: a playback experiment with radio-tagged great tits.

    Science.gov (United States)

    Amy, Mathieu; Sprau, Philipp; de Goede, Piet; Naguib, Marc

    2010-12-07

    Individuals often differ consistently in behaviour across time and contexts, and such consistent behavioural differences are commonly described as personality. Personality can play a central role in social behaviour both in dyadic interactions and in social networks. We investigated whether explorative behaviour, as proxy of personality of territorial male great tits (Parus major), predicts their own and their neighbours' territorial responses towards simulated intruders. Several weeks prior to playback, subjects were taken from the wild to test their exploratory behaviour in a standard context in the laboratory. Exploratory behaviour provides a proxy of personality along a slow-fast explorer continuum. Upon release, males were radio-tracked and subsequently exposed to interactive playback simulating a more or a less aggressive territorial intruder (by either overlapping or alternating broadcast songs with the subjects' songs). At the same time, we radio-tracked a neighbour of the playback subject. Male vocal responses during playback and spatial movements after playback varied according to male explorative behaviour and playback treatment. Males with lower exploration scores approached the loudspeaker less, and sang more songs, shorter songs and songs with slower element rates than did males with higher exploration scores. Moreover, neighbour responses were related to the explorative behaviour of the subject receiving the playback but not to their own explorative behaviour. Our overall findings reveal for the first time how personality traits affect resource defence within a communication network providing new insights on the cause of variation in resource defence behaviour.

  15. Enhancing Radio Access Network Performance over LTE-A for Machine-to-Machine Communications under Massive Access

    Directory of Open Access Journals (Sweden)

    Fatemah Alsewaidi

    2016-01-01

    Full Text Available The expected tremendous growth of machine-to-machine (M2M devices will require solutions to improve random access channel (RACH performance. Recent studies have shown that radio access network (RAN performance is degraded under the high density of devices. In this paper, we propose three methods to enhance RAN performance for M2M communications over the LTE-A standard. The first method employs a different value for the physical RACH configuration index to increase random access opportunities. The second method addresses a heterogeneous network by using a number of picocells to increase resources and offload control traffic from the macro base station. The third method involves aggregation points and addresses their effect on RAN performance. Based on evaluation results, our methods improved RACH performance in terms of the access success probability and average access delay.

  16. Impact of cognitive radio on radio astronomy

    NARCIS (Netherlands)

    Bentum, M.J.; Boonstra, A.J.; Baan, W.A.

    2010-01-01

    The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission

  17. Studying integrated silicon-lens antennas for radio communication systems operated in the 60 GHz frequency band

    Science.gov (United States)

    Artemenko, A. A.; Mal'tsev, A. A.; Maslennikov, R. O.; Sevastyanov, A. G.; Ssorin, V. N.

    2013-01-01

    We consider the development of an integrated lens antenna for LAN radio communication systems operated in the 60 GHz frequency band. The antenna is an extended hemispherical silicon lens. On its flat surface, a microstrip antenna element is located. The use of silicon, which has a dielectric permittivity ɛ = 11.7, as the lens material ensures the maximum range of scanning angles for the minimum axial size of the lens. The approximate analytical formulas, which are used for initial calculations of the lens parameters, allow one to evaluate the basic parameters of the lens antenna integrated with the microstrip antenna element. For further optimizing the parameters of the lens and the antenna element, 3D simulation of the electromagnetic-field distribution was performed. Based on its results, we have developed and manufactured extended hemispherical silicon lenses, which had radii of 6 and 12 mm. The planar microstrip antenna element was manufactured by the low temperature co-fired ceramics (LTCC) technology. The results of simulation and experimental studies of the manufactured prototypes demonstrate that the developed lens antennas has directivities of 17.6 and 23.1 dBi for lenses with radii of 6 and 12 mm, respectively. In this case, the maximum beam deflection angle is achieved, which is equal to 55°, while the permissible decrease in the directivity is no more than 6 dBi compared with the case of a non-deflected beam. The obtained results show that the developed integrated lens antennas can find applications in high-speed radio communication systems operated in the millimeter-wave range.

  18. Simultaneous wireless information and power transfer for spectrum sharing in cognitive radio communication systems

    KAUST Repository

    Benkhelifa, Fatma

    2016-07-26

    In this paper, we consider the simultaneous wireless information and power transfer for the spectrum sharing (SS) in cognitive radio (CR) systems with a multi-antenna energy harvesting (EH) primary receiver (PR). The PR uses the antenna switching (AS) technique that assigns a subset of the PR\\'s antennas to harvest the energy from the radio frequency (RF) signals sent by the secondary transmitter (ST), and assigns the rest of the PR\\'s antennas to decode the information data. In this context, the primary network allows the secondary network to use the spectrum as long as the interference induced by the secondary transmitter (ST)\\'s signals is beneficial for the energy harvesting process at the PR side. The objective of this work is to show that the spectrum sharing is beneficial for both the SR and PR sides and leads to a win-win situation. To illustrate the incentive of the spectrum sharing cognitive system, we evaluate the mutual outage probability (MOP) introduced in [1] which declares an outage event if the PR or the secondary receiver (SR) is in an outage. Through the simulation results, we show that the performance of our system in terms of the MOP is always better than the performance of the system in the absence of ST and improves as the ST-PR interference increases. © 2016 IEEE.

  19. Numerical arc segmentation algorithm for a radio conference: A software tool for communication satellite systems planning

    Science.gov (United States)

    Whyte, W. A.; Heyward, A. O.; Ponchak, D. S.; Spence, R. L.; Zuzek, J. E.

    1988-01-01

    The Numerical Arc Segmentation Algorithm for a Radio Conference (NASARC) provides a method of generating predetermined arc segments for use in the development of an allotment planning procedure to be carried out at the 1988 World Administrative Radio Conference (WARC) on the Use of the Geostationary Satellite Orbit and the Planning of Space Services Utilizing It. Through careful selection of the predetermined arc (PDA) for each administration, flexibility can be increased in terms of choice of system technical characteristics and specific orbit location while reducing the need for coordination among administrations. The NASARC software determines pairwise compatibility between all possible service areas at discrete arc locations. NASARC then exhaustively enumerates groups of administrations whose satellites can be closely located in orbit, and finds the arc segment over which each such compatible group exists. From the set of all possible compatible groupings, groups and their associated arc segments are selected using a heuristic procedure such that a PDA is identified for each administration. Various aspects of the NASARC concept and how the software accomplishes specific features of allotment planning are discussed.

  20. Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations.

    Science.gov (United States)

    Rowley, Jack T; Joyner, Ken H

    2012-01-01

    This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles.

  1. The use of cell phones and radio communication systems to reduce delays in getting help for pregnant women in low- and middle-income countries: a scoping review

    Directory of Open Access Journals (Sweden)

    Sunday O. Oyeyemi

    2015-09-01

    Full Text Available Background: Delays in getting medical help are important factors in the deaths of many pregnant women and unborn children in the low- and middle-income countries (LMIC. Studies have suggested that the use of cell phones and radio communication systems might reduce such delays. Objectives: We review the literature regarding the impact of cell phones and radio communication systems on delays in getting medical help by pregnant women in the LMIC. Design: Cochrane Library, PubMed, Maternity and Infant care (Ovid, Web of Science (ISI, and Google Scholar were searched for studies relating to the use of cell phones for maternal and child health services, supplemented with hand searches. We included studies in LMIC and in English involving the simple use of cell phones (or radio communication to either make calls or send text messages. Results: Fifteen studies met the inclusion criteria. All the studies, while of various designs, demonstrated positive contributory effects of cell phones or radio communication systems in reducing delays experienced by pregnant women in getting medical help. Conclusions: While the results suggested that cell phones could contribute in reducing delays, more studies of a longer duration are needed to strengthen the finding.

  2. Discourse segmentation and the management of multiple tasks in single episodes of air traffic controller-pilot spoken radio communication

    Directory of Open Access Journals (Sweden)

    Paul A. Falzon

    2009-06-01

    Full Text Available Episodes of VHF radio-mediated pilot-controller spoken communication in which multiple tasks are conducted are engendered in and through the skilful deployment and combination, by the parties to the talk, of multiple orders of discourse segmentation. These orders of segmentation are manifest at the levels of transmission design and sequential organisation. Both of these features are analysed from a Conversation Analytic standpoint in order to track their segment by segment genesis, development and completion. From the analysis it emerges that in addition to the serial type of sequential organisations described by Schegloff (1986, there exists an alternative form of organisation that enables tasks to be managed in a quasi-parallel manner, and which affords controllers and pilots a number of practical advantages in the conduct of their radio-mediated service encounters.Cet article présente des extraits d’échanges oraux entre pilots et contrôleurs du ciel via la radio VHF. On peut y voir comment le déploiement et la combinaison habile de plusieurs ordres de segmentation discursive, engageant les deux coénonciateurs de la conversation, leur permet d’accomplir des tâches multiples. Ces ordres de segmentation se manifestent aux niveaux du plan de la transmission et de l’organisation séquentielle. Ces deux niveaux sont envisagées du point de vue de l’analyse conversationnelle dans le but d’examiner, segment après segment, comment ils se mettent en place, se développent puis prennent fin. Notre étude montre que, outre le type sériel d’organisations séquentielles décrit par Schegloff (1986, il existe une forme alternative d’organisation qui permet de gérer les tâches de manière quasi parallèle, et qui fournit aux contrôleurs aériens ainsi qu’aux pilotes de nombreux avantages pratiques dans la conduite de leurs radio.

  3. HF Radio Astronomy from a Small Satellite

    Science.gov (United States)

    2016-06-15

    antenna as shown in Figure 4. Dual mode loop-dipole elements are described in [25,29,30]. The 10 MHz radiation patterns of the six modes are shown in... telemetry , GPS, and vector antenna modules. Robey 14 30th Annual AIAA/USU Conference on Small Satellites Alexander Morris. Thanks to Sara Klein for

  4. Reliable Radio Access for Massive Machine-to-Machine (M2M) Communication

    DEFF Research Database (Denmark)

    Madueño, Germán Corrales

    Machine-to-Machine (M2M) communication is a term that identifies the emerging paradigm of interconnected systems, machines, and things that communicate and collaborate without human intervention. The characteristics of M2M Communications are small payloads and sporadic transmissions, while...... the service requirements can range from massive number of devices to ultra-reliable. This PhD thesis focuses on novel mechanisms to meet these requirements in a variety of wireless systems, from well-established technologies such as cellular networks, to emerging technologies like IEEE 802.11ah. Today...... an overwhelming 89% of the deployed M2M modules are GPRS-based. This motivates us to investigate the potential of GPRS as a dedicated M2M network. We show that by introducing minimal modifications to GPRS operation, a large number of devices can be reliably supported. Surprisingly, even though LTE is seen...

  5. A Novel Pulse Shaping for UWB Impulse Radio IEEE 802.15.4a Communications Systems

    Directory of Open Access Journals (Sweden)

    BARRAJ Imen

    2014-05-01

    Full Text Available This paper presents a novel pulse shape which we call modified triangular pulse (MTri for Impulse Radio-Ultra Wide Band (IR-UWB IEEE 802.15.4a systems. The MTri pulse and UWB shapes previously proposed for low power IR-UWB transceivers topologies are studied and compared. The performance measures considered are compliance with required spectral emission constrains, Mask Loss (ML power and pulse energy. Our theoretical and simulations results show the advantages of the MTri pulse over studies UWB pulses. It presents the lower ML power about 0.45dB and the higher pulse energy of 0.45nJ/p.

  6. Modeling and performance analysis of cooperative communications in cognitive radio networks

    KAUST Repository

    Khabazian, Mehdi

    2011-09-01

    In this paper, we study the performance of a network comprised of a primary user and a secondary user with the latter having cognitive radio capabilities. The secondary node uses the empty slots of the primary user to transmit its own traffic as well as to relay the primary\\'s traffic in a cooperative fashion. Taking a queuing theory approach, we find the probability generating functions of the numbers of packets in the queues of the primary and secondary users. Subsequently, we determine a number of performance measures such as the average queues\\' lengths, average packet transmission delays and secondary user\\'s queue surcharge due to cooperation. The numerical results along with the simulations show the importance of controlling the number of primary user packets admitted by the secondary user for cooperation and its impacts on the other performance measures. © 2011 IEEE.

  7. Evolution of Monolithic Technology for Wireless Communications: GaN MMIC Power Amplifiers For Microwave Radios

    Directory of Open Access Journals (Sweden)

    Vittorio Camarchia

    2014-09-01

    Full Text Available This paper presents the progress of monolithic technology for microwaveapplication, focusing on gallium nitride technology advances in the realization of integratedpower amplifiers. Three design examples, developed for microwave backhaul radios, areshown. The first design is a 7 GHz Doherty developed with a research foundry, while thesecond and the third are a 7 GHz Doherty and a 7–15 GHz dual-band combined poweramplifiers, both based on a commercial foundry process. The employed architectures, themain design steps and the pros and cons of using gallium nitride technology are highlighted.The measured performance demonstrates the potentialities of the employed technology, andthe progress in the accuracy, reliability and performance of the process.

  8. Code-expanded radio access protocol for machine-to-machine communications

    DEFF Research Database (Denmark)

    Thomsen, Henning; Kiilerich Pratas, Nuno; Stefanovic, Cedomir

    2013-01-01

    The random access methods used for support of machine-to-machine, also referred to as Machine-Type Communications, in current cellular standards are derivatives of traditional framed slotted ALOHA and therefore do not support high user loads efficiently. We propose an approach that is motivated b...

  9. Radio Interoperability: Addressing the Real Reasons We Don’t Communicate Well During Emergencies

    Science.gov (United States)

    2006-03-01

    This is an issue we cannot simply “ buy ” our way out of by merely deploying more equipment. 4 Newsday...platforms, thus enabling agency-specific communications to continue?) First responders will tend to revert to daily habits in times of crisis, instead of...recognition of the need for improved human interoperability 16 Y2K refers to millennial change of

  10. Towards Implantable Body Sensor Networks - Performance of MICS Band Radio Communication in Animal Tissue

    NARCIS (Netherlands)

    Karuppiah Ramachandran, Vignesh Raja; Meratnia, Nirvana; Zhang, Kui; Havinga, Paul J.M.

    Reliable wireless communication inside the human body is crucial for the design of implantable body sensor networks (IBSN). The tissues in human body are heterogeneous and have dierent conductivity and permitivity, which make the modeling of the wireless channel challenging. The design of upper

  11. A Study of EL2 Pilots' Radio Communication in the General Aviation Environment

    Science.gov (United States)

    Estival, Dominique; Molesworth, Brett

    2009-01-01

    This paper reports on the preliminary stages of a project designed to investigate communication problems in General Aviation and assess the utility of language technologies as a means of mitigation. The study presented in this paper is the first of a three-part study, in which we aim to investigate the extent to which the English language…

  12. HF Communication Aid Decision-Making Model based on SNR Evaluation%基于信噪比估算的短波通信辅助决策模型研究

    Institute of Scientific and Technical Information of China (English)

    董航; 徐池; 易涛; 韩东

    2014-01-01

    In order to meet the communication commander’s demands on HF communication aid-decision-making in complicated battlefield, the field-intensity prediction model and noise model are simplified and parameter programmed, thus a situation-visualized model based on the evaluation of SNR is proposed,vi-sualization implementation is beneficial to communication commander in grasping the overall situation intui-tively. Meanwhile, HF aid-decision-making model based on the model function of SNR evaluation is con-structed and defined. According to the controllable factors of function, input parameter is reasonably allo-cated via mathematical analysis, thus the aid decision-making information is provided to achieve optimum communication. Rationality of the simulation model is verified through the comparison of between simula-tion prediction result and reference data, and the proposed model can serve as a reference for the research of HF communication aid decision-making.%为满足复杂战场条件下通信指挥员的短波通信决策需求,对场强预测模型和噪声模型进行简化和参数程序化,提出了以短波通信信噪比估算为基础的态势可视化模型,可视化的实现有利于通信指挥员直观地掌握短波通信的整体态势;构建和定义了以信噪比估算模型函数为基础的短波辅助决策模型,根据函数的可控因子,运用数学分析方法对输入参数进行合理配置,为最佳通信效果的实现提供辅助决策信息。通过仿真预测结果和参考数据的对比,验证了仿真模型的合理性,对短波通信的辅助决策研究有一定的参考价值。

  13. 76 FR 67397 - Radio Broadcasting Services; Llano, Texas

    Science.gov (United States)

    2011-11-01

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Llano, Texas AGENCY: Federal Communications Commission... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez,...

  14. 77 FR 59882 - Radio Broadcasting Services; Tignall, GA

    Science.gov (United States)

    2012-10-01

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tignall, GA AGENCY: Federal Communications Commission... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief,...

  15. 76 FR 37049 - Radio Broadcasting Services; Bastrop, LA

    Science.gov (United States)

    2011-06-24

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Bastrop, LA AGENCY: Federal Communications Commission... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa...

  16. 78 FR 32 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2013-01-02

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westley, CA AGENCY: Federal Communications Commission.... 8. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications...

  17. 77 FR 58799 - Radio Broadcasting Services; Roaring Springs, TX

    Science.gov (United States)

    2012-09-24

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Roaring Springs, TX AGENCY: Federal Communications... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez,...

  18. 77 FR 64758 - Radio Broadcasting Services; Randsburg, CA

    Science.gov (United States)

    2012-10-23

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Randsburg, CA AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief,...

  19. Design of a Microstrip Bowtie Antenna for Indoor Radio-Communications

    OpenAIRE

    Fraga-Rosales Hector; Reyes-Ayala Mario; Hernandez-Valdez Genaro; Andrade-Gonzalez Edgar Alejandro; Miranda-Tello Jose Raul; Cruz-Perez Felipe Alejandro; Castellanos-Lopez Sandra Lirio

    2017-01-01

    In this paper, a microstrip bowtie patch antenna (MBPA) for wireless indoor communications is carried out. Here, a microstrip transmission-line feed network was designed in order to match the MBPA. The proposed antenna uses a ground plane with the aim of narrowing down the back lobes in comparison with bowtie sheet antennas, which radiation pattern is omni-directional. The far-field pattern of the antenna was simulated using a finite-element numerical algorithm and obtained by interpolation e...

  20. Interconnection between packet switching national networks and local packet radio communication networks

    Science.gov (United States)

    Talone, P.; Trigila, S.

    1985-07-01

    Multipoint topology networks based on a single statistically distributed radiocommunication channel are considered, referring only to restricted area networks with line of sight type links. The architecture and protocols of such networks are reviewed. The problems related to the interconnection of such networks with large public packet switching communication networks are examined. Several hypothesis are studied concluding that mainly in the case of emergencies or catastrophic events these networks are an extremely useful resource.

  1. Design, Development and Pre-Flight Testing of the Communications, Navigation, and Networking Reconfigurable Testbed (Connect) to Investigate Software Defined Radio Architecture on the International Space Station

    Science.gov (United States)

    Over, Ann P.; Barrett, Michael J.; Reinhart, Richard C.; Free, James M.; Cikanek, Harry A., III

    2011-01-01

    The Communication Navigation and Networking Reconfigurable Testbed (CoNNeCT) is a NASA-sponsored mission, which will investigate the usage of Software Defined Radios (SDRs) as a multi-function communication system for space missions. A softwaredefined radio system is a communication system in which typical components of the system (e.g., modulators) are incorporated into software. The software-defined capability allows flexibility and experimentation in different modulation, coding and other parameters to understand their effects on performance. This flexibility builds inherent redundancy and flexibility into the system for improved operational efficiency, real-time changes to space missions and enhanced reliability/redundancy. The CoNNeCT Project is a collaboration between industrial radio providers and NASA. The industrial radio providers are providing the SDRs and NASA is designing, building and testing the entire flight system. The flight system will be integrated on the Express Logistics Carrier (ELC) on the International Space Station (ISS) after launch on the H-IIB Transfer Vehicle in 2012. This paper provides an overview of the technology research objectives, payload description, design challenges and pre-flight testing results.

  2. 物联网无线技术分析及相关商业应用%Radio Communication Technology and Related Business Applications of Internet of Things

    Institute of Scientific and Technical Information of China (English)

    周明; 司文

    2015-01-01

    Radio communication technology is the core of Internet of things . It includes radio frequency technology ,NFC technology ,Infrared technology ,Wifi technology ,Bluetooth and ZigBee . T his paper analyzes technical characteristics and commercial prospects of these technologies .%无线传输技术是物联网技术的核心。本文以无线射频技术、NFC技术、红外技术、Wifi技术、蓝牙技术、ZigBee技术为切入点,分析了它们的技术特点及在物联网应用中的商业前景。

  3. Ultra Low Power, Radiation Tolerant UHF Radio Technologies for In Situ Communication Applications

    Science.gov (United States)

    Lay, N. E.

    2001-01-01

    For future deep space missions, significant reductions in the mass and power requirements for short-range telecommunication systems will be critical in enabling a wide variety of new mission concepts. These possibilities include penetrators, gliders, miniature rovers, and sensor networks. Under joint funding from NASA's Cross Enterprise and JPL's Telecommunications and Mission technology programs, recent development activity has focused on the design of ultralow mass and power transceiver systems and subsystems suitable for operation in a flight environment. For these efforts, the functionality of the transceiver has been targeted towards a specific Mars communications scenario. However, the overall architecture is well suited to any short or medium range application where a remote probe will aperiodically communicate with a base station, possibly an orbiter, for the eventual purpose of relaying science information back to Earth. In 2001, these sponsors have been augmented with collaborative expertise and funding from JPL's Center for Integrated Space Microsystems in order to migrate existing concepts and designs to a System on a Chip (SOAC) solution. Additional information is contained in the original extended abstract.

  4. Ultra Low Power, Radiation Tolerant UHF Radio Technologies for In Situ Communication Applications

    Science.gov (United States)

    Lay, N. E.

    2001-01-01

    For future deep space missions, significant reductions in the mass and power requirements for short-range telecommunication systems will be critical in enabling a wide variety of new mission concepts. These possibilities include penetrators, gliders, miniature rovers, and sensor networks. Under joint funding from NASA's Cross Enterprise and JPL's Telecommunications and Mission technology programs, recent development activity has focused on the design of ultralow mass and power transceiver systems and subsystems suitable for operation in a flight environment. For these efforts, the functionality of the transceiver has been targeted towards a specific Mars communications scenario. However, the overall architecture is well suited to any short or medium range application where a remote probe will aperiodically communicate with a base station, possibly an orbiter, for the eventual purpose of relaying science information back to Earth. In 2001, these sponsors have been augmented with collaborative expertise and funding from JPL's Center for Integrated Space Microsystems in order to migrate existing concepts and designs to a System on a Chip (SOAC) solution. Additional information is contained in the original extended abstract.

  5. Radio Frequency (RF) Micro-Electromechanical Systems (MEMS) Switches for Space Communications

    Science.gov (United States)

    Simons, Rainee N.; Ponchak, George E.; Scardelletti, Maximillian C.; Varaljay, Nicholas C.

    2000-01-01

    Micro-electromechanical systems (MEMS) is an emerging technology for radio frequency (RF) systems because it has the potential to dramatically decrease loss and improve efficiency. In this paper, we address the design and fabrication of novel MEMS switches being developed at NASA Glenn Research Center. Two types of switches are being developed: a microstrip series single pole single throw (SPST) switch and a coplanar waveguide (CPW) series SPST and single pole double throw (SPDT) switches. These are being fabricated as an integral part of 50 Ohm microstrip and CPW RF integrated circuits using microfabrication techniques. The construction of the switch relies on a cantilever beam that is partially supported by a dielectric post. The cantilever beam is electro-magnetically actuated. To decrease stiction, a Si3N4 thin film is deposited over the contact area. Thus, when the switch is closed, the ON-state insertion loss is governed by the parallel plate capacitance formed by the two contacts. The isolation in the OFF-state is governed by the parasitic capacitance when the cantilever is in the up position. RF MEMS switches have been demonstrated with 80% lower insertion loss than conventional solid state devices (GaAs Metal Semiconductor Field Effect Transistors (MESFETs) and Silicon PIN diodes) based switches. For example, a conventional GaAs five-bit phase shifter which is required for beam steering in a phased array antenna has approximately 7 dB of insertion loss at 26.5 GHz where as a comparable MEMS based phase shifter is expected to have only 2 dB of insertion loss. This translates into 56% lower power dissipation and therefore decreases the thermal load on the spacecraft and also reduces the power amplifier requirements. These benefits will enable NASA to build the next generation of deep space science crafts and micro/nano satellites.

  6. Android在数字集群通信终端中的应用%Application of Android in digital trunked radio communication terminal

    Institute of Scientific and Technical Information of China (English)

    谢拥军; 鄢楚平; 汪涵

    2012-01-01

    为了使数字集群通信终端智能化并兼容Android平台丰富的应用,对如何将目前流行的智能操作系统Android应用到数字集群通信终端中进行了研究和实现.对于数字集群通信终端的重要组成部分——电话系统,详细地分析了Android自带的Telephony框架,然后根据TETRA数字集群系统的特点对Telephony框架进行了修改,最后对已修改的Android系统在TI的OMAP3530平台上进行了验证,实现了数字集群通信终端特有的功能.%To intelligentize the digital trunked radio communication terminal and make it compatible with the abundant applications of Android platform, the problemon how to apply the current popular smartphone's Android operating system is researched and implemented to digital trunked radio communication terminal. For the important part of digital trunked radio communication terminal, the telephony framework is analyzed in detail. Then, the telephony system is modified according to the characteristics of the TETRA digital trunked system. At last, the modified Android system is verified on the OMAP3530 platform of texas instruments, and achieved the specific features of the digital trunked communication terminal.

  7. Radio frequency fields generated by the S-band communication link on OV102

    Science.gov (United States)

    Murphy, G. B.; Shawhan, S. D.

    1984-01-01

    The Space Shuttle STS-3 mission carried a Plasma Diagnostics Package (PDP) whose instrumentation included an S-band antenna and detector. The PDP was maneuvered by the Remote Manipulator System arm through a computer controlled sequence in the Orbiter's X-Z plane, above the quad and hemi S-band communications antennas. Antenna field strength measurements were conducted during transmitter high power modes, and the results were compared to ground full scale measurements and predictions. A field strength 4.8 + or - 3 dB higher than predicted is noted. This RF field is primarily due to the quad PM transmitter, whose power output of 115 W compares with 15 W for the hemi.

  8. An implementation of Software Defined Radios for federated aerospace networks: Informing satellite implementations using an inter-balloon communications experiment

    Science.gov (United States)

    Akhtyamov, Rustam; Cruz, Ignasi Lluch i.; Matevosyan, Hripsime; Knoll, Dominik; Pica, Udrivolf; Lisi, Marco; Golkar, Alessandro

    2016-06-01

    Novel space mission concepts such as Federated Satellite Systems promise to enhance sustainability, robustness, and reliability of current missions by means of in-orbit sharing of space assets. This new paradigm requires the utilization of several technologies in order to confer flexibility and re-configurability to communications systems among heterogeneous spacecrafts. This paper illustrates the results of the experimental demonstration of the value proposition of federated satellites through two stratospheric balloons interoperating with a tracking ground station through Commercial Off-The-Shelf Software Defined Radios (SDRs). The paper reports telemetry analysis and characterizes the communications network that was realized in-flight. Furthermore, it provides details on an in-flight anomaly experienced by one of the balloons, which was recovered through the use of the federated technology that has been developed. The anomaly experienced led to the early loss of the directional link from the ground station to the affected stratospheric balloon node after 15 min in flight. Nevertheless, thanks to the federated approach among the systems, the ground station was still able to retrieve the balloon's data in real time through the network system, for which the other balloon operated as a federated relay for 45 min in flight, uninterrupted. In other words, the federated approach to the system allowed triplicating the useful lifetime of the defective system, which would have not been possible to realize otherwise. Such anomaly coincidentally demonstrated the value of the federated approach to space systems design. The paper paves the way for future tests on space assets.

  9. ExtraHF survey

    DEFF Research Database (Denmark)

    Piepoli, Massimo F; Binno, Simone; Corrà, Ugo

    2015-01-01

    AIMS: In heart failure (HF), exercise training programmes (ETPs) are a well-recognized intervention to improve symptoms, but are still poorly implemented. The Heart Failure Association promoted a survey to investigate whether and how cardiac centres in Europe are using ETPs in their HF patients...... of evidence on safety or benefit was cited. When implemented, an ETP was proposed to all HF patients in only 55% of the centres, with restriction according to severity or aetiology. CONCLUSIONS: With respect to previous surveys, there is evidence of increased availability of ETPs in HF in Europe, although too...

  10. [Effects of radio- and microwaves emitted by wireless communication devices on the functions of the nervous system selected elements].

    Science.gov (United States)

    Politański, Piotr; Bortkiewicz, Alicja; Zmyślony, Marek

    Nervous system is the most "electric" system in the human body. The research of the effects of electromagnetic fields (EMFs) of different frequencies on its functioning have been carried out for years. This paper presents the results of the scientific literature review on the EMF influence on the functioning of the human nervous system with a particular emphasis on the recent studies of the modern wireless communication and data transmission systems. In the majority of the analyzed areas the published research results do not show EMF effects on the nervous system, except for the influence of GSM telephony signal on resting EEG and EEG during patients' sleep and the influence of radiofrequency EMF on the cardiovascular regulation. In other analyzed areas (EMF impact on sleep, the evoked potentials and cognitive processes), there are no consistent results supporting any influence of electromagnetic fields. Neurophysiological studies of the effect of radio- and microwaves on the brain functions in humans are still considered inconclusive. This is among others due to, different exposure conditions, a large number of variables tested, deficiencies in repeatability of research and statistical uncertainties. However, methodological guidelines are already available giving a chance of unifying research that definitely needs to be continued in order to identify biophysical mechanisms of interaction between EMFs and the nervous system. One of the EMF research aspects, on which more and more attention is paid, are inter-individual differences. Med Pr 2016;67(3):411-421.

  11. Spectrum management and radio resource management considering cognitive radio systems

    NARCIS (Netherlands)

    Haartsen, Jaap C.; Wieweg, Lasse; Huschke, Jörg

    2005-01-01

    International fora and some national administrations define a cognitive radio (CR) as a pioneering radio communication system that would be capable of altering and adapting its transmitter and receiver parameters based on communication and the exchange of information with related detectable radio co

  12. Perencanaan dan analisis kehandalan sistem komunikasi radio microwave tampak pandang pada pita frekuensi 12750-13250 MHz [Planning and analysis of the reliability of line of sight microwave radio communication system on 12750-13250 MHz band

    Directory of Open Access Journals (Sweden)

    Ahmad Hasyim

    2016-12-01

    Full Text Available Propagasi gelombang radio dapat diartikan sebagai proses perambatan gelombang radio dari pemancar ke penerima. Gelombang ini akan merambat melalui udara bebas menuju antena penerima dan mengalami redaman di sepanjang lintansannya,  redaman perangkat dan saluran transmisi, sehingga ketika sampai di antena penerima, energi sinyal sudah sangat lemah. Line of sight    (LOS merupakan salah satu jenis propagasi di mana diantara stasiun pengirim dan stasiun penerima  tidak terdapat penghalang. Kendala geografis dan kelengkungan bumi menyebabkan adanya keterbatasan untuk transmisi line of sight, namun masalah ini secara umum dapat dikurangi melalui perencanaan, perhitungan dan penggunaan teknologi tambahan. Dalam perencanaan sistem komunikasi radio, kinerja LOS perlu direncanakan cadangan daya akibat fluktuasi sinyal serta analisis kehandalannya. Sistem radio gelombang mikro digital antar titik yang menggunakan  frekuensi 13 GHz dengan modulasi 16 QAM, bit rate 140 MBps,dan  noise figure 0,7 dB memerlukan daya pancar -4,488 dBm, fading margin sebesar 85,51 dB dan kehandalannya sebesar 99,9999999%.*****Radio wave propagation can be defined as the process of propagation of radio waves from the transmitter to the receiver. These waves will propagate through free air towards the receiver antena with experienced curbs along the tracks, so when it arrive at the receiver antena, the signal energy is very slow. Line of sight (LOS is one kind of propagation where no obstacles found between the transmitter and the receiver station. Geographical constraints and the curvature of the earth bring limitations to the line of sight transmission, but this problem can generally be reduced through planning, calculation and use of additional technologies. In a radio communication system planning, LOS performance needs to be planned caused by signal fluctuations and reliability. Digital microwave point to point radio systems using 13 GHz of spectrum, 16 QAM of

  13. Design of a Microstrip Bowtie Antenna for Indoor Radio-Communications

    Directory of Open Access Journals (Sweden)

    Fraga-Rosales Hector

    2017-01-01

    Full Text Available In this paper, a microstrip bowtie patch antenna (MBPA for wireless indoor communications is carried out. Here, a microstrip transmission-line feed network was designed in order to match the MBPA. The proposed antenna uses a ground plane with the aim of narrowing down the back lobes in comparison with bowtie sheet antennas, which radiation pattern is omni-directional. The far-field pattern of the antenna was simulated using a finite-element numerical algorithm and obtained by interpolation employing near-field equipment. The experimental results are described in detail intending to agree well with the simulated predictions. The antenna was designed, measured and built and its far field performance was evaluated with a 2.11 GHz resonant frequency. The azimuth and elevation antenna patterns, antenna gain and, the matching frequency were the main parameters obtained to analyze the antenna behaviour. The antenna has a gain approximately equal to 8.77 dBi and its beam-widths are higher than 100° in E plane.

  14. Cognitive radio technology and its application in military communication%认知无线电技术及在军事通信中的应用

    Institute of Scientific and Technical Information of China (English)

    费利军; 王亚鸽

    2014-01-01

    The cognitive radio(CR)is a new concept following the software radio in the communication field,and it focu-ses on the adjusting the system running parameters on the basis of sensing surrounding. The concept of CR and its relation with software radio are described in this paper. Its structure and key technologies are introduced. The advantages of CR in the mili-tary communication and the challenge it is facing are analyzed. It has a positive role in upgrade construction of the communica-tion systems in China.%认知无线电是通信领域在软件无线电概念之后出现的又一新概念,其主要关注于系统通过感知操作环境的变化调整系统工作参数。叙述了认知无线电的概念及与软件无线电的关系,对其构架和关键技术进行了介绍,并分析了认知无线电在军事通信领域的优势及面临的挑战,对于我军通信系统的升级建设具有积极作用。

  15. Large ionospheric disturbances produced by the HAARP HF facility

    Science.gov (United States)

    Bernhardt, Paul A.; Siefring, Carl L.; Briczinski, Stanley J.; McCarrick, Mike; Michell, Robert G.

    2016-07-01

    The enormous transmitter power, fully programmable antenna array, and agile frequency generation of the High Frequency Active Auroral Research Program (HAARP) facility in Alaska have allowed the production of unprecedented disturbances in the ionosphere. Using both pencil beams and conical (or twisted) beam transmissions, artificial ionization clouds have been generated near the second, third, fourth, and sixth harmonics of the electron gyrofrequency. The conical beam has been used to sustain these clouds for up to 5 h as opposed to less than 30 min durations produced using pencil beams. The largest density plasma clouds have been produced at the highest harmonic transmissions. Satellite radio transmissions at 253 MHz from the National Research Laboratory TACSat4 communications experiment have been severely disturbed by propagating through artificial plasma regions. The scintillation levels for UHF waves passing through artificial ionization clouds from HAARP are typically 16 dB. This is much larger than previously reported scintillations at other HF facilities which have been limited to 3 dB or less. The goals of future HAARP experiments should be to build on these discoveries to sustain plasma densities larger than that of the background ionosphere for use as ionospheric reflectors of radio signals.

  16. 78 FR 32165 - Commercial Radio Operators; Correction

    Science.gov (United States)

    2013-05-29

    ... COMMISSION 47 CFR Part 0 Commercial Radio Operators; Correction AGENCY: Federal Communication Commission...) Administers the Commission's commercial radio operator program (part 13 of this chapter); the Commission's... rules concerning radio operator licenses for maritime and aviation in order to reduce...

  17. Sex-specific responses to territorial intrusions in a communication network: Evidence from radio-tagged great tits.

    Science.gov (United States)

    Snijders, Lysanne; van Oers, Kees; Naguib, Marc

    2017-02-01

    Signals play a key role in the ecology and evolution of animal populations, influencing processes such as sexual selection and conflict resolution. In many species, sexually selected signals have a dual function: attracting mates and repelling rivals. Yet, to what extent males and females under natural conditions differentially respond to such signals remains poorly understood, due to a lack of field studies that simultaneously track both sexes. Using a novel spatial tracking system, we tested whether or not the spatial behavior of male and female great tits (Parus major) changes in relation to the vocal response of a territorial male neighbor to an intruder. We tracked the spatial behavior of male and female great tits (N = 44), 1 hr before and 1 hr after simulating territory intrusions, employing automatized Encounternet radio-tracking technology. We recorded the spatial and vocal response of the challenged males and quantified attraction and repulsion of neighboring males and females to the intrusion site. We additionally quantified the direct proximity network of the challenged male. The strength of a male's vocal response to an intruder induced sex-dependent movements in the neighborhood, via female attraction and male repulsion. Stronger vocal responders were older and in better body condition. The proximity networks of the male vocal responders, including the number of sex-dependent connections and average time spent with connections, however, did not change directly following the intrusion. The effects on neighbor movements suggest that the strength of a male's vocal response can provide relevant social information to both the males and the females in the neighborhood, resulting in both sexes adjusting their spatial behavior in contrasting ways, while the social proximity network remained stable. This study underlines the importance of "silent" eavesdroppers within communication networks for studying the dual functioning and evolution of sexually

  18. COMMUNICATIONS

    CERN Multimedia

    L. Taylor and D. Barney

    2010-01-01

    CMS Centres, Outreach and the 7 TeV Media Event The new CMS Communications group is now established and is addressing three areas that are critical to CMS as it enters the physics operations phase: - Communications Infrastructure, including almost 50 CMS Centres Worldwide, videoconferencing systems, and CERN meeting rooms - Information systems, including the internal and external Web sites as well as the document preparation and management systems - Outreach and Education activities, including working with print, radio and TV media, visits to CMS, and exhibitions. The group has been active in many areas, with the highest priority being accorded to needs of CMS operations and preparations for the major media event planned for 7 TeV collisions. Unfortunately the CMS Centre@CERN suffered a major setback when, on 21st December, a cooling water pipe froze and burst on the floor above the CMS Centre main room. Water poured through the ceiling, flooding the floor and soaking some of the consoles, before e...

  19. Transformations of Radio Aesthetics

    Directory of Open Access Journals (Sweden)

    Grażyna Stachyra

    2015-09-01

    Full Text Available The paper presents some remarks upon the nature of contemporary radio communications in the context of the terms “aesthetics” and “aesthetisation”. The latter, denoting a process of turning aesthetic phenomena into unaesthetic ones, becomes the dominant strategy of formatted radio. The “surface aesthetisation,” which provides mainly pleasure and entertainment, transcends the simple styling of objects or environment and appears to be a more significant strand of contemporary culture. The article shows several examples of “surface” modelling of radio programming and explains their purpose in radio communication.

  20. Ham radio for dummies

    CERN Document Server

    Silver, H Ward

    2013-01-01

    An ideal first step for learning about ham radio Beyond operating wirelessly, today's ham radio operators can transmit data and pictures; use the Internet, laser, and microwave transmitters; and travel to places high and low to make contact. This hands-on beginner guide reflects the operational and technical changes to amateur radio over the past decade and provides you with updated licensing requirements and information, changes in digital communication (such as the Internet, social media, and GPS), and how to use e-mail via radio. Addresses the critical use of ham radio for replacing downe

  1. Remote Tropospheric Radio Communication,

    Science.gov (United States)

    1980-03-19

    large F ricd cbservazicns. 7rkm the same distribution they find Thus, V’e= - this median valie cf five minute : ms values. PFge 15. qunning in forward... multipla -prongel tropcsEleric cnanrel; te .Feed cf these changes is from the pcrtions of tle hertz tc several hertz. Characteristic VOC = 30025107 PAGE...not exceed 0.2-0.3 vs. Therefore vith the pulsp sethcd cf mcasurenent trinsmitter must emni Fulsas on tle crier of 0.1 and even 0.05 ms . Cnly than at

  2. Diffusion of Hf and Nb in Zr-19%Nb

    Energy Technology Data Exchange (ETDEWEB)

    Zou, H. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Hood, G.M. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Schultz, R.J. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Matsuura, N. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Roy, J.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Jackman, J.A. [CANMET, Ottawa, Ont. (Canada). Met. Sci. and Technol.

    1996-05-01

    Diffusion of Hf and Nb in large-grained bcc Zr-19%Nb has been studied. Diffusion coefficients of Hf, D(Hf), were measured in the range 620-1173 K and D(Nb) was measured at 920 and 1167 K. The Hf diffusion profiles were determined by SIMS and the Nb profiles by microtome sectioning and radio-tracer counting. The Hf data show a smooth, temperature-dependent behaviour through the monotectoid temperature, 875 K, and may be characterised by D{approx}10{sup -9}.exp-1.4 (eV/kT) m{sup 2}/s. D(Nb) tends to be lower than the corresponding values for D(Hf). Overall, diffusion of Hf and Nb are characteristic of diffusion in bcc Zr. Surface hold-up (oxide film) at low temperatures was overcome by using ion-implanted Hf diffusion sources. The results are compared with earlier work and discussed in terms of diffusion mechanisms and the {beta}-phase transformation of commercial Zr-2.5Nb. (orig.).

  3. Investigation and Development of Data-Driven D-Region Model for HF Systems Impacts

    Science.gov (United States)

    Eccles, J. V.; Rice, D.; Sojka, J. J.; Hunsucker, R. D.

    2002-01-01

    Space Environment Corporation (SEC) and RP Consultants (RPC) are to develop and validate a weather-capable D region model for making High Frequency (HF) absorption predictions in support of the HF communications and radar communities. The weather-capable model will assimilate solar and earth space observations from NASA satellites. The model will account for solar-induced impacts on HF absorption, including X-rays, Solar Proton Events (SPE's), and auroral precipitation. The work plan includes: I . Optimize D-region model to quickly obtain ion and electron densities for proper HF absorption calculations. 2. Develop indices-driven modules for D-region ionization sources for low, mid, & high latitudes including X-rays, cosmic rays, auroral precipitation, & solar protons. (Note: solar spectrum & auroral modules already exist). 3. Setup low-cost monitors of existing HF beacons and add one single-frequency beacon. 4. Use PENEX HF-link database with HF monitor data to validate D-region/HF absorption model using climatological ionization drivers. 5. Develop algorithms to assimilate NASA satellite data of solar, interplanetary, and auroral observations into ionization source modules. 6. Use PENEX HF-link & HF-beacon data for skill score comparison of assimilation versus climatological D-region/HF absorption model. Only some satellites are available for the PENEX time period, thus, HF-beacon data is necessary. 7. Use HF beacon monitors to develop HF-link data assimilation algorithms for regional improvement to the D-region/HF absorption model.

  4. Communications via the radio artificial earth satellite: Design of the tracking diagram and features for conducting QSO

    Science.gov (United States)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

    A detailed examination is made of the operation of a transmitting artifical Earth satellite. A tracking diagram for the satellite is constructed. The zone of radio visibility can be determined based on the techniques proposed.

  5. The Cognition of Multiaircraft Control (MAC): Cognitive Ability Predictors, Working Memory, Interference, and Attention Control in Radio Communication

    Science.gov (United States)

    2015-03-26

    throughout this process and to my committee members Dr. Elshaw and Dr. Finomore for their feedback and help. I couldn’t have done it without all of you...to them when they are spoken in the form of radio calls. They also have to perform this task in the presence of distracting, and sometimes...amount of time lapse between the time when the radio call was spoken and the time the participant pressed enter after typing their numerical response

  6. Far-Field Testing Method of Spurious Emission Produced by HF RFID

    OpenAIRE

    Nikola Gvozdenovic; Ralph Prestros; Mecklenbräuker, Christoph F.

    2016-01-01

    We present measurements of spurious emission produced by high-frequency radio frequency identification (HF RFID) using carrier frequency of 13.56 MHz. HF RFID tags produce unwanted emission due to rectification and more generally due to nonlinearity of analog front end. Depending on the conducting material of an HF RFID coil and surrounding dielectric material, the coil behaves as more or less good antenna on some harmonic frequencies. Exact characterization and analysis of unwanted emission ...

  7. An orbital angular momentum radio communication system optimized by intensity controlled masks effectively: Theoretical design and experimental verification

    Science.gov (United States)

    Gao, Xinlu; Huang, Shanguo; Wei, Yongfeng; Zhai, Wensheng; Xu, Wenjing; Yin, Shan; Zhou, Jing; Gu, Wanyi

    2014-12-01

    A system of generating and receiving orbital angular momentum (OAM) radio beams, which are collectively formed by two circular array antennas (CAAs) and effectively optimized by two intensity controlled masks, is proposed and experimentally investigated. The scheme is effective in blocking of the unwanted OAM modes and enhancing the power of received radio signals, which results in the capacity gain of system and extended transmission distance of the OAM radio beams. The operation principle of the intensity controlled masks, which can be regarded as both collimator and filter, is feasible and simple to realize. Numerical simulations of intensity and phase distributions at each key cross-sectional plane of the radio beams demonstrate the collimated results. The experimental results match well with the theoretical analysis and the receive distance of the OAM radio beam at radio frequency (RF) 20 GHz is extended up to 200 times of the wavelength of the RF signals, the measured distance is 5 times of the original measured distance. The presented proof-of-concept experiment demonstrates the feasibility of the system.

  8. Mid-Latitude Mobile Wideband HF- NVIS Channel Analysis: Part 1

    Science.gov (United States)

    2017-09-14

    communications (SATCOM) for beyond line-of- sight (LOS) links. However, standard HF systems operating over a 3-kHz bandwidth do not provide sufficient...wideband mid-latitude HF channel soundings and three-dimensional (3-D) ray-tracing simulations to develop a statistical model of a particular nearly...46 5 THE HF-NVIS CHANNEL SOUNDING SYSTEM ...................................................................... 47 5.1 TRANSMIT AND RECEIVE HF

  9. Cognitive Wireless Communications - A paradigm shift in dealing with radio resources as a prerequisite for the wireless network of the future - An overview on the topic of cognitive wireless technologies

    Science.gov (United States)

    Haustein, Thomas; Stanczak, Slawomir; Wolisz, Adam; Jondral, Friedrich; Schotten, Hans; Kraemer, Rolf; Mück, Markus; Mennenga, Horst; Bender, Paul

    2016-07-01

    Wireless radio communications systems form the basis for mobile network connections in the digital society. A limited amount of radio spectrum and a spatially densified use of wireless communications systems require a resource-efficient use of the spectrum. Mechanisms of cognitive radio may hold the key to a more efficient use of the available spectrum under consideration of quality of service requirements. These mechanisms take advantage of location-specific knowledge of the wireless channel occupation in the dimensions of frequency, time, location and direction in space and therefore enable co-existent and reliable wireless communication. The authors give an introduction to the status of cognitive wireless communication technology, which represents the starting point of a series of research projects promoted by BMBF during 2012-2014.

  10. Low-Frequency Waves in HF Heating of the Ionosphere

    Science.gov (United States)

    Sharma, A. S.; Eliasson, B.; Milikh, G. M.; Najmi, A.; Papadopoulos, K.; Shao, X.; Vartanyan, A.

    2016-02-01

    Ionospheric heating experiments have enabled an exploration of the ionosphere as a large-scale natural laboratory for the study of many plasma processes. These experiments inject high-frequency (HF) radio waves using high-power transmitters and an array of ground- and space-based diagnostics. This chapter discusses the excitation and propagation of low-frequency waves in HF heating of the ionosphere. The theoretical aspects and the associated models and simulations, and the results from experiments, mostly from the HAARP facility, are presented together to provide a comprehensive interpretation of the relevant plasma processes. The chapter presents the plasma model of the ionosphere for describing the physical processes during HF heating, the numerical code, and the simulations of the excitation of low-frequency waves by HF heating. It then gives the simulations of the high-latitude ionosphere and mid-latitude ionosphere. The chapter also briefly discusses the role of kinetic processes associated with wave generation.

  11. 76 FR 13579 - Radio Broadcasting Services; Hebbronville, TX

    Science.gov (United States)

    2011-03-14

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Hebbronville, TX AGENCY: Federal Communications..., Radio broadcasting. For the reasons discussed in the preamble, the Federal Communications...

  12. 78 FR 3877 - Radio Broadcasting Services; Peach Springs, AZ

    Science.gov (United States)

    2013-01-17

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal Communications..., Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  13. 76 FR 67375 - Radio Broadcasting Services; Various Locations

    Science.gov (United States)

    2011-11-01

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications..., Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  14. 77 FR 16800 - Radio Broadcasting Services; Westfield, NY

    Science.gov (United States)

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office ] FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westfield, NY AGENCY: Federal Communications..., Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  15. 78 FR 27342 - Radio Broadcasting Services; Moran, Texas

    Science.gov (United States)

    2013-05-10

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Moran, Texas AGENCY: Federal Communications Commission..., Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  16. Radio Astronomy Explorer /RAE/. I - Observations of terrestrial radio noise.

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.; Stone, R. G.

    1973-01-01

    Radio Astronomy Explorer (RAE) I data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial radio noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 dB and more above cosmic noise background, on frequencies above the F-layer critical frequency.

  17. Experimental Investigation of Subject-Specific On-Body Radio Propagation Channels for Body-Centric Wireless Communications

    Directory of Open Access Journals (Sweden)

    Mohammad Monirujjaman Khan

    2014-01-01

    Full Text Available In this paper, subject-specific narrowband (2.45 GHz and ultra-wideband (3–10.6 GHz on-body radio propagation studies in wireless body area networks (WBANs were performed by characterizing the path loss for eight different human subjects of different shapes and sizes. The body shapes and sizes of the test subjects used in this study are characterised as thin, medium build, fatty, shorter, average height and taller. Experimental investigation was made in an indoor environment using a pair of printed monopoles (for the narrowband case and a pair of tapered slot antennas (for the ultra-wideband (UWB case. Results demonstrated that, due to the different sizes, heights and shapes of the test subjects, the path loss exponent value varies up to maximum of 0.85 for the narrowband on-body case, whereas a maximum variation of the path loss exponent value of 1.15 is noticed for the UWB case. In addition, the subject-specific behaviour of the on-body radio propagation channels was compared between narrowband and UWB systems, and it was deduced that the on-body radio channels are subject-specific for both narrowband and UWB system cases, when the same antennas (same characteristics are used. The effect of the human body shape and size variations on the eight different on-body radio channels is also studied for both the narrowband and UWB cases.

  18. 77 FR 75946 - Radio Broadcasting Services; Dove Creek, CO

    Science.gov (United States)

    2012-12-26

    ... COMMISSION 47 CFR Part 73 . Radio Broadcasting Services; Dove Creek, CO AGENCY: Federal Communications... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant... Communications Commission proposes to amend 47 CFR Part 73 as follows: PART 73--RADIO BROADCAST SERVICES 1....

  19. Frederiksberg HF kursus

    DEFF Research Database (Denmark)

    Lindstrøm, Maria Duclos

    2008-01-01

    Notatet bygger på et interviewmateriale med dimitterede HF-kursister 3 måneder efter endt eksamen. Notatet undersøger dels, hvad der har hjulpet til at gennemføre, dels hvad der har været negativt og vanskeligt ved uddannelsen. Endvidere belyser notatet hvad kursisterne oplever at tage med fra de...

  20. The coexistence of cognitive radio and radio astronomy

    NARCIS (Netherlands)

    Bentum, Marinus Jan; Boonstra, A.J.; Baan, W.A.

    2009-01-01

    An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio

  1. The coexistence of cognitive radio and radio astronomy

    NARCIS (Netherlands)

    Bentum, M.J.; Boonstra, A.J.; Baan, W.A.

    2009-01-01

    An increase of the efficiency of spectrum usage requires the development of new communication techniques. Cognitive radio may be one of those new technique, which uses unoccupied frequency bands for communications. This will lead to more power in the bands and therefore an increasing level of Radio

  2. Radio propagation measurement and channel modelling

    CERN Document Server

    Salous, Sana

    2013-01-01

    While there are numerous books describing modern wireless communication systems that contain overviews of radio propagation and radio channel modelling, there are none that contain detailed information on the design, implementation and calibration of radio channel measurement equipment, the planning of experiments and the in depth analysis of measured data. The book would begin with an explanation of the fundamentals of radio wave propagation and progress through a series of topics, including the measurement of radio channel characteristics, radio channel sounders, measurement strategies

  3. 77 FR 50053 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2012-08-20

    ... 73 Radio, Radio broadcasting. Federal Communications Commission. Peter H. Doyle, Chief, Audio.... FOR FURTHER INFORMATION CONTACT: Michael Wagner, Media Bureau, (202) 418-2700 or Rolanda F. Smith...

  4. 47 CFR 95.201 - (R/C Rule 1) What is the Radio Control (R/C) Radio Service?

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false (R/C Rule 1) What is the Radio Control (R/C) Radio Service? 95.201 Section 95.201 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PERSONAL RADIO SERVICES Radio Control (R/C) Radio Service...

  5. Communication

    NARCIS (Netherlands)

    Sigafoos, J.; Lancioni, G.E.; O'Reilly, M.F.; Lang, R.; Singh, N.N.; Didden, H.C.M.; Green, V.A.; Marschik, P.B.

    2016-01-01

    Communication disorders are common among people with intellectual disabilities. Consequently, enhancing the communication skills of such individuals is a major intervention priority. This chapter reviews the nature and prevalence of the speech, language, and communication problems associated with

  6. Unmanned Aviation Systems Models of the Radio Communications Links: Study Results - Appendices Annex 2. Volume 1 and Volume 2

    Science.gov (United States)

    Birr, Richard B.; Spencer, Roy; Murray, Jennifer; Lash, Andrew

    2013-01-01

    This report describes the analysis of communications between the Control Station and an Unmanned Aircraft (UA) flying in the National Airspace System (NAS). This work is based on the RTCA SC-203 Operational Services and Environment Description (OSED). The OSED document seeks to characterize the highly different attributes of all UAs navigating the airspace and define their relationship to airspace users, air traffic services, and operating environments of the NAS. One goal of this report is to lead to the development of Minimum Aviation System Performance Standards for Control and Communications. This report takes the nine scenarios found in the OSED and analyzes the communication links.

  7. Résonateurs à ondes acoustiques guidées sur miroir de Bragg pour communications radio-fréquences

    OpenAIRE

    2010-01-01

    National audience; Les résonateurs à ondes acoustiques de volumes (appelés résonateurs BAW pour Bulk Acoustic Wave) sont des composants particulièrement attractifs pour les communications radio-fréquences (f > 1 GHz). Ils permettent de réaliser des filtres aux performances accrues et aux encombrements et coûts réduits, ou d'intégrer des oscillateurs de référence à faible consommation. Les résonateurs BAW classiques possèdent une fréquence de fonctionnement fixe déterminée principalement par l...

  8. Flexible Adaptation in Cognitive Radios

    CERN Document Server

    Li, Shujun

    2013-01-01

    This book provides an introduction to software-defined radio and cognitive radio, along with methodologies for applying knowledge representation, semantic web, logic reasoning and artificial intelligence to cognitive radio, enabling autonomous adaptation and flexible signaling. Readers from the wireless communications and software-defined radio communities will use this book as a reference to extend software-defined radio to cognitive radio, using the semantic technology described. Readers with a background in semantic web and artificial intelligence will find in this book the application of semantic web and artificial intelligence technologies to wireless communications. For readers in networks and network management, this book presents a new approach to enable interoperability, collaborative optimization and flexible adaptation of network components. Provides a comprehensive ontology covering the core concepts of wireless communications using a formal language; Presents the technical realization of using a ...

  9. Farmer participation in radio campaigns for technology adoption:

    African Journals Online (AJOL)

    Peter Berglez

    Key words: radio campaign, participation, radio production, adoption, ... from the AFRRI hybrid maize campaign in Mangochi, Malawi, Journal of ... communication action research project whose goal was to investigate how radio and modern.

  10. Wireless radio a history

    CERN Document Server

    Coe, Lewis

    2006-01-01

    ""Informative...recommended""--Choice; ""interesting...a good read...well worth reading""--Contact Magazine. This history first looks at Marconi's wireless communications system and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

  11. Recent advances in high-capacity free-space optical and radio-frequency communications using orbital angular momentum multiplexing

    Science.gov (United States)

    Willner, Alan E.; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Li, Long; Zhao, Zhe; Wang, Jian; Tur, Moshe; Molisch, Andreas F.; Ashrafi, Solyman

    2017-02-01

    There is a continuing growth in the demand for data bandwidth, and the multiplexing of multiple independent data streams has the potential to provide the needed data capacity. One technique uses the spatial domain of an electromagnetic (EM) wave, and space division multiplexing (SDM) has become increasingly important for increased transmission capacity and spectral efficiency of a communication system. A subset of SDM is mode division multiplexing (MDM), in which multiple orthogonal beams each on a different mode can be multiplexed. A potential modal basis set to achieve MDM is to use orbital angular momentum (OAM) of EM waves. In such a system, multiple OAM beams each carrying an independent data stream are multiplexed at the transmitter, propagate through a common medium and are demultiplexed at the receiver. As a result, the total capacity and spectral efficiency of the communication system can be multiplied by a factor equal to the number of transmitted OAM modes. Over the past few years, progress has been made in understanding the advantages and limitations of using multiplexed OAM beams for communication systems. In this review paper, we highlight recent advances in the use of OAM multiplexing for high-capacity free-space optical and millimetre-wave communications. We discuss different technical challenges (e.g. atmospheric turbulence and crosstalk) as well as potential techniques to mitigate such degrading effects. This article is part of the themed issue 'Optical orbital angular momentum'.

  12. Recent advances in high-capacity free-space optical and radio-frequency communications using orbital angular momentum multiplexing.

    Science.gov (United States)

    Willner, Alan E; Ren, Yongxiong; Xie, Guodong; Yan, Yan; Li, Long; Zhao, Zhe; Wang, Jian; Tur, Moshe; Molisch, Andreas F; Ashrafi, Solyman

    2017-02-28

    There is a continuing growth in the demand for data bandwidth, and the multiplexing of multiple independent data streams has the potential to provide the needed data capacity. One technique uses the spatial domain of an electromagnetic (EM) wave, and space division multiplexing (SDM) has become increasingly important for increased transmission capacity and spectral efficiency of a communication system. A subset of SDM is mode division multiplexing (MDM), in which multiple orthogonal beams each on a different mode can be multiplexed. A potential modal basis set to achieve MDM is to use orbital angular momentum (OAM) of EM waves. In such a system, multiple OAM beams each carrying an independent data stream are multiplexed at the transmitter, propagate through a common medium and are demultiplexed at the receiver. As a result, the total capacity and spectral efficiency of the communication system can be multiplied by a factor equal to the number of transmitted OAM modes. Over the past few years, progress has been made in understanding the advantages and limitations of using multiplexed OAM beams for communication systems. In this review paper, we highlight recent advances in the use of OAM multiplexing for high-capacity free-space optical and millimetre-wave communications. We discuss different technical challenges (e.g. atmospheric turbulence and crosstalk) as well as potential techniques to mitigate such degrading effects.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

  13. Acquisition and Development of a Cognitive Radio Based Wireless Monitoring and Surveillance Testbed for Future Battlefield Communications Research

    Science.gov (United States)

    2015-03-01

    controllability compared to WiFi -based solutions. In addition, the testbed is a programmable yet fully controlled setup for implementation and testing...processing, communication range extension and using the USRP2’s wideband nature to capture multiple IEEE 802.15.4 channels simultaneously. We faced several

  14. High Efficiency Traveling-Wave Tube Power Amplifier for Ka-Band Software Defined Radio on International Space Station-A Platform for Communications Technology Development

    Science.gov (United States)

    Simons, Rainee N.; Force, Dale A.; Kacpura, Thomas J.

    2013-01-01

    The design, fabrication and RF performance of the output traveling-wave tube amplifier (TWTA) for a space based Ka-band software defined radio (SDR) is presented. The TWTA, the SDR and the supporting avionics are integrated to forms a testbed, which is currently located on an exterior truss of the International Space Station (ISS). The SDR in the testbed communicates at Ka-band frequencies through a high-gain antenna directed to NASA s Tracking and Data Relay Satellite System (TDRSS), which communicates to the ground station located at White Sands Complex. The application of the testbed is for demonstrating new waveforms and software designed to enhance data delivery from scientific spacecraft and, the waveforms and software can be upgraded and reconfigured from the ground. The construction and the salient features of the Ka-band SDR are discussed. The testbed is currently undergoing on-orbit checkout and commissioning and is expected to operate for 3 to 5 years in space.

  15. Radio broadcasting via satellite

    Science.gov (United States)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  16. 78 FR 37474 - Radio Broadcasting Services; Dove Creek, Colorado

    Science.gov (United States)

    2013-06-21

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Dove Creek, Colorado AGENCY: Federal Communications... CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Chief, Audio... amends 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority citation for...

  17. 78 FR 71557 - Radio Broadcasting Services; Tohatchi, New Mexico

    Science.gov (United States)

    2013-11-29

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tohatchi, New Mexico AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio... proposes to amend 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The authority...

  18. 75 FR 82279 - Radio Broadcasting Services; Various Locations

    Science.gov (United States)

    2010-12-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 As stated in the preamble, the Federal Communications Commission amends 47 CFR part 73 as follows: PART 73--RADIO BROADCASTING SERVICES 0 1....

  19. Pulsed inductive HF laser

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  20. 76 FR 42573 - Radio Broadcasting Services; Oklahoma and Texas

    Science.gov (United States)

    2011-07-19

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Oklahoma and Texas AGENCY: Federal Communications... Review filed by Rawhide Radio, LLC, Capstar TX Limited Partnership, Clear Channel Broadcasting...

  1. 47 CFR 90.185 - Multiple licensing of radio transmitting equipment in the mobile radio service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Multiple licensing of radio transmitting equipment in the mobile radio service. 90.185 Section 90.185 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES...

  2. Radio Journalism.

    Science.gov (United States)

    Bittner, John R.; Bittner, Denise A.

    This book, a how-to-do-it guide for the novice and the professional alike, deals with several aspects of radio journalism: producing documentaries, preparing and announcing radio news, ethics and responsibility, regulation of radio journalism, and careers. It traces the history and growth of radio news, shows its impact on the public, and…

  3. Design of Discrete Time Radio Receiver for the Demodulation of Power-Separated Co-Channel Satellite Communication Signals

    Science.gov (United States)

    2013-09-01

    video broadcasting [7]. ViaSat-1 (pictured in Figure 1), a high capacity Ka - band communications satellite went into service on 16 January 2012 as the...Video Broadcasting- satellite , Second Generation 8PSK 8- Phase Shift Keying GTED Gardner Timing Error Detector HP High Power signal, in layered...Spectral Density QPSK Quadrature Phase Shift Keying SCADA Supervisory Control and Data Acquisition SNR Signal to Noise Ratio SRRC Squared Raised

  4. Smart Radio Spectrum Management for Cognitive Radio

    Directory of Open Access Journals (Sweden)

    Partha Pratim Bhattacharya

    2011-08-01

    Full Text Available Today’s wireless networks are characterized by fixed spectrum assignment policy. The limited availablespectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm toexploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wirelesscommunication in which either a network or a wireless node changes its transmission or receptionparameters to communicate efficiently avoiding interference with licensed or unlicensed users. It cancapture best available spectrum to meet user communication requirements (spectrum management. Inthis work, a fuzzy logic based system for spectrum management is proposed where the radio can shareunused spectrum depending on parameters like distance, signal strength, node velocity and availabilityof unused spectrum. The system is simulated and is found to give satisfactory results.

  5. Effective MIMO Model Zero-Forcing Decoding for Multi-group Space-Time Coding in HF Communications%短波通信多组空时编码中等效MIMO模型ZF解码

    Institute of Scientific and Technical Information of China (English)

    康瑞琪; 葛利嘉; 张振宇

    2016-01-01

    面向短波通信提出了多组空时编码( MGSTC )的一种等效多输入多输出( MIMO )模型迫零( ZF)解码算法。该算法以降低运算复杂度为目的,将原多时隙MIMO系统拆分为多个多时隙单输入多输出( SIMO)系统并分别等效为多个新的单时隙MIMO系统模型,通过各自左乘等效信道矩阵的共轭转置后进行最大比合并( MRC)以及ZF解码获得发送信号估计值,避免了球形解码( SD)中对高阶矩阵的QR分解。仿真结果表明,与虚拟MIMO模型SD解码算法相比,等效MIMO模型ZF解码算法在误码率( BER)性能1 dB损耗的情况下,运算量降低一个数量级以上。%This paper proposes an effective multiple-input multiple-output( MIMO) model zero-forcing( ZF) decoding algorithm for multi-group space-time coding( MGSTC) in high frequency( HF) communications. To reduce the computation complexity,the algorithm divides the original multiple-time-slot MIMO system into some multiple time slot single-input multiple-output( SIMO) systems each of which is equivalent to new sin-gle-time-slot MIMO system model. After left multiplying transpose of effective channel matrix separately, maximal ratio combine( MRC) and ZF decoding are performed to obtain signal estimation,thus avoiding high-order matrix QR decomposition in sphere decoding(SD). The simulation results show that compared with virtual MIMO model SD decoding algorithm,the effective MIMO model ZF decoding has lower than one order of magnitude in computation complexity with 1 dB loss in bit error rate( BER) performance.

  6. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Nanjing University of Posts and Telecommunications, School of Tongda, Nanjing (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Zhuge, L.J. [Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Soochow University, Analysis and Testing Center, Suzhou (China); Wu, X.M. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai (China)

    2015-01-23

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO{sub x} are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf{sup 2+} and Hf{sup 4+}. The HfErO films are composed with the structures of HfO{sub 2}, HfO and ErO{sub x}, which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO{sub 2} in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO{sub 2} are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  7. 47 CFR 73.758 - System specifications for digitally modulated emissions in the HF broadcasting service.

    Science.gov (United States)

    2010-10-01

    ... emissions in the HF broadcasting service. 73.758 Section 73.758 Telecommunication FEDERAL COMMUNICATIONS... § 73.758 System specifications for digitally modulated emissions in the HF broadcasting service. (a... digital audio broadcasting and datacasting are authorized. The RF requirements for the DRM system...

  8. 基于安全性评估的民用客机VHF通信电台架构*%Civil Airliner VHF Communication Radio Architecture Based on Safety Assessment

    Institute of Scientific and Technical Information of China (English)

    郑力; 廖祯林

    2013-01-01

    The airworthiness certification for civil airliner VHF communication radio requires device-level safety assessment . This paper briefly outlines the airborne systems and equipment safety assessment guidelines,meth-ods and process . Then it describes the failure modes for each module to compose a VHF communication radioand modular failure rate,and figures out the failure probability of single-channel architecture VHF communica-tion radio with the fault tree method recommended by SAE ARP 4761 . The estimation result indicates that itdoes not meet the fail probability requirements allocated by aircraft grade PSSA (Preliminary System Safety As-sessment). Finally,the non-similar multi-channel architecture of VHF communication radio is proposed in order to reduce the failure probability of the radio . Analysis shows that VHF communication radio with this implemen-tation architecture can achieve lower failure probability than ordinary single-channel implementation architecture VHF communication radio.%  进行设备级的安全性评估是民用客机VHF通信电台适航审定的要求。简述了机载系统和设备的安全性评估指南、方法及过程,描述了VHF通信电台各组成模块的失效模式及失效率,并运用SAE ARP 4761所推荐的故障树方法估算出了单通道架构VHF通信电台的失效概率,估算结果说明单通道架构VHF通信电台不能满足飞机级PSSA(Preliminary System Safety Assessment)分配的失效概率要求。最后,为了降低VHF通信电台的失效概率,提出了VHF通信电台的非相似多通道实现架构。分析表明,与单通道架构相比,非相似多通道实现架构的VHF通信电台具有更低的失效概率。

  9. Investigation on possible risks to human health by exposure to the radiation of electromagnetic waves produced by the radio communications; Investigacion sobre posibles riesgos a la salud humana por exposicion a la radiacion de ondas electromagneticas producidas por las radiocomunicaciones

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Hernandez, Carlos Felipe; Ibarguengoytia Gonzalez, Pablo Hector; Flores Garcia, Andres; Franco Campos, Laura Elena [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2011-06-13

    This verification procedure is based on a research work on the possible risks to human health by exposure to the radiation of electromagnetic waves produced by the radio communications, cases of study: cellular telephony, radio digital troncalized and wireless telephony IP of Voice on IP (wireless local area network). The revision of all the international standards and the applicable national standardization was included, as well as the verification of fulfillment. [Spanish] Este procedimiento de verificacion esta basado en un trabajo de investigacion sobre posibles riesgos a la salud humana por exposicion a la radiacion de ondas electromagneticas producidas por la radiocomunicaciones, casos de estudio: telefonia celular, radio troncalizado digital y telefonia IP inalambrica de Voz sobre IP (red de area local inalambrica). Se incluyo la revision de todos los estandares internacionales y de la normatividad nacional aplicable, asi como la verificacion de cumplimiento.

  10. The Radio Phenomenon in Italy.

    Science.gov (United States)

    Faenza, Roberto

    One in a series of studies of experiments in new audiovisual techniques in Europe and the situations in some member countries, this paper traces the development of radio in Italy. Opposing views about radio broadcasting (public monopoly vs. freedom of broadcasting) are examined, and the various political and legal aspects of communications in…

  11. A Study and Design of a Configurable CDMA Communication Platform

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Software radio.Software radio, together with digital radio as its basis, has been the trends to development in wireless communications. Digital radio focuses on all-digitalization techniques and modularization methods in communication systems, while software radio pays more attention to all-digialtized radio's software structure and opening architecture.

  12. 多径分量噪声干扰下无线电扩频通信优化技术%Optimization of radio spread spectrum communication under multipath component noise interference

    Institute of Scientific and Technical Information of China (English)

    邸珩烨

    2016-01-01

    The radio spread spectrum communication is subjected to the interference of the multipath component noise, which leads to the poor communication channel equalization, the ability of anti interference is not strong, and the bit error rate is high. Noise interference suppression is needed to improve the quality of radio spread spectrum communication. An optimization technique of radio spread spectrum communication based on adaptive cascade notch and inter symbol interference suppression is proposed in the paper. The paper presents the construction of radio spread spectrum communication system transmission structure model, and selects an adaptive notch filter to decrease the noise of the spread spectrum radio multipath components, which reduces the signal access to in band interference power, improves the demodulator output signal⁃to⁃noise ratio and signal to stem ratio. With the expansion of the sequence to modulate the carrier, the signal is moved to the carrier frequency, furthermore channel equalization is realized , and anti⁃interference ability is improved. Simulation results show that the proposed algorithm can effectively reduce the bit error rate of spread spectrum communication, and improve the communication quality.%无线电扩频通信受到多径分量噪声的干扰,导致通信信道均衡性不好,抗干扰能力不强,误码率较高。需要进行噪声干扰抑制,改善无线电扩频通信质量。提出一种基于自适应级联陷波和码间干扰抑制的无线电扩频通信优化技术。构建无线电扩频通信系统传输结构模型,采用自适应陷波器对无线电扩频通信中的多径分量噪声进行有效抑制,降低了进入信号通频带内的干扰功率,提高解调器的输出信噪比和信干比。采用扩展后的序列去调制载波,将信号搬移到载频上,实现信道均衡,提高抗干扰能力。仿真结果表明,该算法能有效降低无线电扩频

  13. The digital sport radio.

    Directory of Open Access Journals (Sweden)

    Hilario José ROMERO BEJARANO

    2014-07-01

    Full Text Available Radio has been immersed in recent years in a phase of technological integration and business of multimedia, as well as diversification of systems and channels for broadcasting. In addition, Internet has been consolidated as the platform of digital radio that more has evolved as a result of its continued expansion. However, the merger radio-Internet must be understood as a new form of communication, and not solely as a new complementary medium. In this context, it is of great interest to analyze that transformations in the way of reception, contents, languages, programs and schedules, has brought with it for the radio that integration. To this end is taken as main reference the sports areas, a key aspect and broadly representative of the current broadcasting landscape.

  14. The Implementation of a High-Frequency Radio Frequency Identification System with a Battery-Free Smart Tag for Orientation Monitoring

    Directory of Open Access Journals (Sweden)

    Tilen Svete

    2017-01-01

    Full Text Available Energy-harvesting passive RFID (radio frequency identification tags provide countless possibilities as so-called smart tags. Smart tags can communicate with existing RFID readers or interrogators while providing a battery-less platform for internal and external sensors to enrich available information about the environment and smart tag it. A reduced cost and size as well as an increased lifespan and durability of battery-free smart tags offer improvements in areas such as transportation and product tracking. Battery-free smart tags can ideally support arbitrarily complex sensor measurements, but in reality energy limitations can introduce great reductions in operating range and thus application range. In this work, we present an example application of a smart tag with a passive HF (high-frequency RFID tag IC (integrated circuit and MEMS (micro electro-mechanical structure sensor. A standard HF RFID reader connected to a PC (personal computer allowed the RF (radio frequency field to power and communicate with the smart tag. A Kalman filter, implemented on a PC, was used to correct and improve the raw sensor data of smart tag orientation. Measurement results showed that the MEMS sensor on the smart tag could be powered for continuous operation and that raw smart tag orientation data could be read while in the RF field of a standard HF RFID reader, but at a limited range.

  15. 78 FR 23150 - Commercial Radio Operators

    Science.gov (United States)

    2013-04-18

    ... COMMISSION 47 CFR Parts 0, 1, 13, 80 and 87 Commercial Radio Operators AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: This document amends our rules concerning commercial radio operator... hold an appropriate commercial radio operator license. The Commission initiated this proceeding...

  16. Marburg Hemorrhagic Fever (Marburg HF)

    Science.gov (United States)

    ... CDC Cancel Submit Search The CDC Marburg hemorrhagic fever (Marburg HF) Note: Javascript is disabled or is ... first recognized in 1967, when outbreaks of hemorrhagic fever occurred simultaneously in laboratories in Marburg and Frankfurt, ...

  17. Hf Transition Probabilities and Abundances

    CERN Document Server

    Lawler, J E; Labby, Z E; Sneden, C; Cowan, J J; Ivans, I I

    2006-01-01

    Radiative lifetimes from laser-induced fluorescence measurements, accurate to about +/- 5 percent, are reported for 41 odd-parity levels of Hf II. The lifetimes are combined with branching fractions measured using Fourier transform spectrometry to determine transition probabilities for 150 lines of Hf II. Approximately half of these new transition probabilities overlap with recent independent measurements using a similar approach. The two sets of measurements are found to be in good agreement for measurements in common. Our new laboratory data are applied to refine the hafnium photospheric solar abundance and to determine hafnium abundances in 10 metal-poor giant stars with enhanced r-process abundances. For the Sun we derive log epsilon (Hf) = 0.88 +/- 0.08 from four lines; the uncertainty is dominated by the weakness of the lines and their blending by other spectral features. Within the uncertainties of our analysis, the r-process-rich stars possess constant Hf/La and Hf/Eu abundance ratios, log epsilon (Hf...

  18. Design for human factors (DfHF): a grounded theory for integrating human factors into production design processes.

    Science.gov (United States)

    Village, Judy; Searcy, Cory; Salustri, Filipo; Patrick Neumann, W

    2015-01-01

    The 'design for human factors' grounded theory explains 'how' human factors (HF) went from a reactive, after-injury programme in safety, to being proactively integrated into each step of the production design process. In this longitudinal case study collaboration with engineers and HF Specialists in a large electronics manufacturer, qualitative data (e.g. meetings, interviews, observations and reflections) were analysed using a grounded theory methodology. The central tenet in the theory is that when HF Specialists acclimated to the engineering process, language and tools, and strategically aligned HF to the design and business goals of the organisation, HF became a means to improve business performance. This led to engineers 'pulling' HF Specialists onto their team. HF targets were adopted into engineering tools to communicate HF concerns quantitatively, drive continuous improvement, visibly demonstrate change and lead to benchmarking. Senior management held engineers accountable for HF as a key performance indicator, thus integrating HF into the production design process. Practitioner Summary: Research and practice lack explanations about how HF can be integrated early in design of production systems. This three-year case study and the theory derived demonstrate how ergonomists changed their focus to align with design and business goals to integrate HF into the design process.

  19. Communications

    Science.gov (United States)

    Bailenson, Jeremy; Buzzanell, Patrice; Deetz, Stanley; Tewksbury, David; Thompson, Robert J.; Turow, Joseph; Bichelmeyer, Barbara; Bishop, M. J.; Gayeski, Diane

    2013-01-01

    Scholars representing the field of communications were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Jeremy Bailenson, Patrice Buzzanell, Stanley Deetz, David Tewksbury, Robert J. Thompson, and…

  20. Transient dynamics of secondary radiation from an HF pumped magnetized space plasma

    NARCIS (Netherlands)

    Norin, L.; Grach, S. M.; Thide, B.; Sergeev, E. N.; Leyser, T. B.

    2007-01-01

    In order to systematically analyze the transient wave and radiation processes that are excited when a high-frequency (HF) radio wave is injected into a magnetized space plasma, we have measured the secondary radiation, or stimulated electromagnetic emission ( SEE), from the ionosphere, preconditione

  1. Imaging HF-induced large-scale irregularities above HAARP

    Science.gov (United States)

    Djuth, Frank T.; Reinisch, Bodo W.; Kitrosser, David F.; Elder, John H.; Snyder, A. Lee; Sales, Gary S.

    2006-02-01

    The University of Massachusetts-Lowell digisonde is used with the HAARP high-frequency (HF), ionospheric modification facility to obtain radio images of artificially-produced, large-scale, geomagnetic field-aligned irregularities. F region irregularities generated with the HAARP beam pointed in the vertical and geomagnetic field-aligned directions are examined in a smooth background plasma. It is found that limited large-scale irregularity production takes place with vertical transmissions, whereas there is a dramatic increase in the number of source irregularities with the beam pointed parallel to the geomagnetic field. Strong irregularity production appears to be confined to within ~5° of the geomagnetic zenith and does not fill the volume occupied by the HF beam. A similar effect is observed in optical images of artificial airglow.

  2. 75 FR 52872 - Radio Broadcasting Services; Blythe, CA

    Science.gov (United States)

    2010-08-30

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Blythe, CA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Prescott Valley Radio Broadcasting... Congressional Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  3. HF omnidirectional spectral CW auroral radar (HF-OSCAR) at very high latitude. Part 1: Technique

    Science.gov (United States)

    Olesen, J. K.; Jacobsen, K. E.; Stauning, P.; Henriksen, S.

    1983-12-01

    An HF system for studies of very high latitude ionospheric irregularities was described. Radio aurora from field-aligned E-region irregularities of the Slant E Condition type were discussed. The complete system combines an ionosonde, a 12 MHz pulse radar and a 12 MHz bistatic CW Doppler-range set-up. The two latter units use alternately a 360 deg rotating Yagi antenna. High precision oscillators secure the frequency stability of the Doppler system in which the received signal is mixed down to a center frequency of 500 Hz. The Doppler shift range is max + or - 500 Hz. The received signal is recorded in analog form on magnetic tape and may be monitored visually and audibly. Echo range of the CW Doppler signal is obtained by a 150 Hz amplitude modulation of the transmitted signal and phase comparison with the backscattered signal.

  4. Radio archive

    OpenAIRE

    Street, Sean

    2008-01-01

    The Centre for Broadcasting History Research, in association with the\\ud British Universities Film and Video Council, is developing an online\\ud audio archive of UK commercial radio, from 1973 to 1992. Work produced\\ud before the Broadcasting Act 1990 represents a different ethos to the role\\ud commercial radio played, and subsequently,continues to play, in the UK.\\ud The change in commercial radio since this period is extraordinary. It is\\ud impossible for the young student of radio, born si...

  5. 75 FR 52649 - Radio Broadcasting Services; DeBeque, Colorado

    Science.gov (United States)

    2010-08-27

    ... COMMISSION 47 CFR Part 73 . Radio Broadcasting Services; DeBeque, Colorado AGENCY: Federal Communications... Congressional Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 As stated in the preamble, the Federal Communications Commission amends 47 CFR part 73...

  6. 77 FR 58800 - Radio Broadcasting Services; Knox City, TX

    Science.gov (United States)

    2012-09-24

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Knox City, TX AGENCY: Federal Communications....415 and 1.420. ] List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications... Commission requests comment on a petition filed by Big Cat Broadcasting, LLC, proposing to amend the Table...

  7. Adaptive Baseband Processing Techniques for Cognitive Radio Systems

    NARCIS (Netherlands)

    Budiarjo, I.

    2009-01-01

    Cognitive Radio is a new paradigm in the wireless communications. It puts the intelligence and awareness dimension to the radio communication system. A Cognitive Radio system will be aware of the changing condition in its environment. The awareness in this thesis is related to the spectrum and the c

  8. 49 CFR 220.35 - Ending a radio transmission.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Ending a radio transmission. 220.35 Section 220.35 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD COMMUNICATIONS Radio and Wireless Communication Procedures § 220.35 Ending a radio transmission....

  9. 78 FR 12622 - Radio Broadcasting Services; Greenup, IL

    Science.gov (United States)

    2013-02-25

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Greenup, IL AGENCY: Federal Communications Commission... 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. ]...

  10. 77 FR 50630 - Radio Broadcasting Services; Westfield, NY

    Science.gov (United States)

    2012-08-22

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westfield, NY AGENCY: Federal Communications... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  11. 78 FR 4078 - Radio Broadcasting Services; Hebbronville, TX

    Science.gov (United States)

    2013-01-18

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Hebbronville, TX AGENCY: Federal Communications... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  12. 77 FR 43216 - Radio Broadcasting Services; Randsburg, CA

    Science.gov (United States)

    2012-07-24

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Randsburg, CA AGENCY: Federal Communications....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...

  13. 75 FR 71044 - Radio Broadcasting Services; Onekama, MI

    Science.gov (United States)

    2010-11-22

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Onekama, MI AGENCY: Federal Communications Commission... CFR Part 73 Radio, Radio broadcasting. 0 For the reasons discussed in the preamble, the...

  14. 75 FR 76294 - Radio Broadcasting Services; Fairbanks, AK

    Science.gov (United States)

    2010-12-08

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Fairbanks, AK AGENCY: Federal Communications... Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0...

  15. 78 FR 25591 - Radio Broadcasting Services; Crownpoint, New Mexico

    Science.gov (United States)

    2013-05-02

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Crownpoint, New Mexico AGENCY: Federal Communications... Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR part 73 Radio, Radio broadcasting....

  16. 78 FR 12010 - Radio Broadcasting Services; Pearsall, Texas

    Science.gov (United States)

    2013-02-21

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Pearsall, Texas AGENCY: Federal Communications....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...

  17. 77 FR 32900 - Radio Broadcasting Services; Llano, TX

    Science.gov (United States)

    2012-06-04

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Llano, TX AGENCY: Federal Communications Commission... Congressional Review Act, see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  18. 76 FR 12292 - Radio Broadcasting Services; Kualapuu, HI

    Science.gov (United States)

    2011-03-07

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Kualapuu, HI AGENCY: Federal Communications Commission..., see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. For the...

  19. 77 FR 52292 - Radio Broadcasting Services; Greenup, IL

    Science.gov (United States)

    2012-08-29

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Greenup, IL AGENCY: Federal Communications Commission....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...

  20. 76 FR 36384 - Radio Broadcasting Services; Brackettville, TX

    Science.gov (United States)

    2011-06-22

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Brackettville, TX AGENCY: Federal Communications..., see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting....

  1. 77 FR 62481 - Radio Broadcasting Services; Crownpoint, NM

    Science.gov (United States)

    2012-10-15

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Crownpoint, NM AGENCY: Federal Communications....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...

  2. 77 FR 76936 - Radio Broadcasting Services; Tignall, GA

    Science.gov (United States)

    2012-12-31

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Tignall, GA AGENCY: Federal Communications Commission..., see U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting....

  3. 78 FR 26739 - Radio Broadcasting Services; Ehrenberg, Arizona

    Science.gov (United States)

    2013-05-08

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Ehrenberg, Arizona AGENCY: Federal Communications... filed by S and H Broadcasting, LLC, proposing the substitution of Channel 228C2 for vacant Channel 286C2... Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa...

  4. Electron Acceleration by High Power Radio Waves in the Ionosphere

    Science.gov (United States)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  5. 78 FR 42700 - Radio Broadcasting Services; Various Locations

    Science.gov (United States)

    2013-07-17

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Various Locations AGENCY: Federal Communications... broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio Division, Media...

  6. Modulation of auroral electrojet currents using dual HF beams with ELF phase offset

    Science.gov (United States)

    Golkowski, M.; Cohen, M.; Moore, R. C.

    2012-12-01

    The modulation of naturally occuring ionospheric currents with high power radio waves in the high frequency (HF, 3-10 MHz) band is a well known technique for generation of extremely low frequency (ELF, 3-3000 Hz) and very low frequency (VLF, 3-30 kHz) waves. We use the heating facility of the High Frequency Active Auroral Research Program (HAARP) to investigate the effect of using dual HF beams with an ELF/VLF phase offset between the modulation waveforms. Experiments with offset HF beams confirm the model of independent ELF/VLF sources. Experiments with co-located HF beams exhibit interaction between the first and second harmonics of the modulated tones when square and sine wave modulation waveforms are employed. Using ELF/VLF phase offsets for co-loacted beams is also shown to be a potential diagnostic for the D-region ionospheric profile.

  7. Spread Spectrum Mobile Radio Communications.

    Science.gov (United States)

    1984-09-15

    seconds, yielding Z Y a =XMZ m M .-m The sequence of operacions is illustrated by the matrices of figures ’--3- and 1-3b. Each matrix is either a...sequence of K-bit numbers (code word, address, detection matrix) or a frequency-time spectrogram (traasmit spectrum, receive spectrum). The matrices pertain...and a reduced rank-sum receiver. In figure 3-1, we show the operation of a MRSR by means of matrices . 3-1 Reduced Rank-Sum Receiver With the values of

  8. Paperbacks in Mass Communication

    Science.gov (United States)

    Hardt, Hanno

    1978-01-01

    Lists paperback books on mass communication, divided into six categories: history and biography; appraisals of the press, law, and ethics; cultural, psychological, and social aspects; radio, television, film, photography; international communication; and journalism techniques, miscellaneous. (GW)

  9. Design and applications of emergency communication network based on cognitive radio%基于认知无线电的应急通信网络设计与应用

    Institute of Scientific and Technical Information of China (English)

    王海涛; 陈晖; 张学平; 张祯松

    2013-01-01

    针对应急通信网络可靠性较低且不能充分利用稀缺网络资源等缺陷,利用认知无线电实时频谱感知和伺机频谱接入提高频谱资源利用率的优点,在资源受限的条件下,构建了一种基于认知无线电的应急通信网络.这种认知应急通信网络将对传统的公共应急通信系统进行升级改造,采用4层网络体系架构,是一种建立在底层异构物理网络上的软件可调节网络.认知应急通信网络互联整合事发现场的各种专用应急通信系统并进行QoS反馈控制,以提高应急通信服务的可靠性和可用性.实例分析表明,这种应急通信网络可通过资源实时感知和自适应管理缓解紧急情况下的资源紧缺问题,适用于多种应急场景.%Emergency communication network is low reliability and cannot exploit scarce network resource.Cognitive radio can improve spectrum utilization by real-time spectrum sensing and opportunistic spectrum access,emergency communications network based on cognitive radio is built in the resource-constrained conditions.This kind of cognitive emergency communication network will upgrade and modify traditional public emergency communication systems.Meanwhile,it adopts four-layered network architecture and is a software adjustable network based on underlying heterogeneous physical networks.It interconnects various special emergency communication systems in the scene and performs QoS feedback control to improve reliability and availability of emergency communication services.Case analysis shows that the emergency communication network based on cognitive radio can solve the shortage of resources in emergency situations by resource real-time perception and adaptive management and is applicable to a variety of emergency scenarios.

  10. Radio Transmitters and Tower Locations, County owned/operated emergency communications towers, Published in 2013, 1:600 (1in=50ft) scale, Waupaca County Land Information.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Radio Transmitters and Tower Locations dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from Orthoimagery information as of 2013. It...

  11. Simulation study of communication link for Pioneer Saturn/Uranus atmospheric entry probe. [signal acquisition by candidate modem for radio link

    Science.gov (United States)

    Hinrichs, C. A.

    1974-01-01

    A digital simulation is presented for a candidate modem in a modeled atmospheric scintillation environment with Doppler, Doppler rate, and signal attenuation typical of the radio link conditions for an outer planets atmospheric entry probe. The results indicate that the signal acquisition characteristics and the channel error rate are acceptable for the system requirements of the radio link. The simulation also outputs data for calculating other error statistics and a quantized symbol stream from which error correction decoding can be analyzed.

  12. Highly survivable communications: Complementary media packet switched networks

    Science.gov (United States)

    Yavuz, D.; Eken, F.; Karavassilis, N.

    1994-07-01

    The requirement for highly survivable communications (HSC) for essential command functions in military operations does not need any justification. The ability to communicate under extreme jamming levels and adverse propagation conditions, including high altitude nuclear events, is a very important requirement. There are also many natural disaster related requirements that also need such highly survivable communications. The prevalent and in a sense classical, approach to provide highly assured connectivity can be summarized as follows: Take a particular propagation medium and try to obtain the ultimate performance from it. There are many examples of this philosophy some successful, most not. Our approach, on the other hand, is to use complementary multi-media or mixed-media where communication links utilizing essentially commercial-off-the-shelf (COTS) equipment are integrated using packet radio (PR) techniques. There is also, in our view, an even more fundamental, recently discovered consideration why the expectation of continuous incremental refinement of a system using a given single media may be be achievable. This is derived from the theory of 'deterministic uncertainty' or more popularly known as 'theory of CHAOS', systems whose state space behavior has fractal characteristics. We will elaborate on this novel argument. Complementary multi-media approach has been the focus for all HSC communications activities at STC since 1982. The original STC studies and prototypes were in response to requirements of broadcasting (i.e., one-way transmission) information. A high frequency (HF)/meteorburst (MB) system was developed/prototyped/tested demonstrating the cost effectiveness of the approach. These results are reviewed. More recently, in 1992 STC has completed the development/test of an Open Systems Interconnection (OSI) HF packet radio protocol as no such open or non-proprietary protocol exists. This protocol has been fully tested, documented and made available to

  13. COMMUNICATIONS

    CERN Document Server

    A. Petrilli

    2013-01-01

    The organisation of the Open Days at the end of September was the single biggest effort of the CMS Communications Group this year. We would like to thank all volunteers for their hard work to show our Point 5 facilities and explain science and technology to the general public. During two days more than 5,000 people visited the CMS detector underground and profited from the surface activities, which included an exhibition on CMS, a workshop on superconductivity, and an activity for our younger visitors involving wooden Kapla blocks. The Communications Group took advantage of the preparations to produce new CMS posters that can be reused at other venues. Event display images have been produced not just for this occasion but also for other exhibits, education purposes, publications etc. During the Open Days, Gilles Jobin, 2012 winner of CERN Collide@CERN prize, performed his Quantum show in Point 5, with the light installation of German artist Julius von Bismarck. Image 3: CERN Open Days at CMS wel...

  14. Protocols for Impulse Radio UWB Ad Hoc Networks

    NARCIS (Netherlands)

    Shi, N.

    2010-01-01

    Ultra Wideband (UWB) technology offers an unprecedented opportunity to further accelerate the evolution of wireless communication and expand the application landscape by enabling outstanding capabilities. UWB radio is fundamentally different from most radio technologies, e.g., Bluetooth, WLAN, etc.

  15. An Effective Fault Diagnosis Strategy of Test Point Optimization for Communication Radio Station%一种高效的通信电台测试点优化故障诊断策略

    Institute of Scientific and Technical Information of China (English)

    李文元; 闫海华; 姚宏杰

    2013-01-01

    For the problems of test diagnosis for communication radio stations,a method based on GADPSO and rule of maximum diagnosis information is presented to solve the fault diagnosis of communication radio stations by optimizing the test point' s fault-test matrix. As the genetic operator is introduced into the DPSO,the algorithm is used to find the optimum test points. By adopting maximum fault diagnosis information, test order can be selected based on the information. The result shows that the GADPSO has better computation efficiency and precision. The GADPSO not only avoids the local optimization and premature convergence,but also improves the searching efficiency. Rule of maximum diagnosis information can estimate test points and is fast and effective in finding the test order. It offers an efficient method for the fault diagnosis strategy of communication radio station.%针对通信电台的测试诊断问题,通过建立“故障-测试”相关性矩阵,提出了一种GADPSO算法与最大诊断信息量准则结合进行通信电台故障诊断的方法.GADPSO算法收敛速度快、计算精度高,既避免了陷入局部最优和早熟收敛,又提高了优化效率;最大诊断信息量准则能全面评判测试点,快速有效地获得测试顺序.该方法为通信电台故障诊断提供了一种高效诊断策略.

  16. Radio systems engineering a tutorial approach

    CERN Document Server

    Santos, Héctor J De Los; Ponte, Juan

    2015-01-01

    This book is intended for readers who already have knowledge of devices and circuits for radio-frequency (RF) and microwave communication and are ready to study the systems engineering-level aspects of modern radio communications systems. The authors provide a general overview of radio systems with their components, focusing on the analog parts of the system and their non-idealities. Based on the physical functionality of the various building blocks of a modern radio system, block parameters are derived, which allows the examination of their influence on the overall system performance. The dis

  17. Communications and Information Sharing (CIS) Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — TheCommunications and Information Sharing (CIS) Laboratory is a Public Safety interoperable communications technology laboratory with analog and digital radios, and...

  18. Wideband high frequency (HF) skywave channel parameters from narrowband measurements

    Science.gov (United States)

    Hausman, Cynthia L.; Uffelman, Donald R.; Walton, Thomas L.

    The HF wideband channel allow the use of spread-spectrum techniques to provide covert communications with low probability of intercept (LPI) and antijam protection. The objective of this work is to determine the extent to which oblique narrowband channel measurements can be used to infer effects in the wideband skywave channel. If oblique narrowband channel measurements can be used as a basis for developing wideband channel models, a large number of existing narrowband measurements can be made available for this task.

  19. Radio interferometry and satellite tracking

    CERN Document Server

    Kawase, Seiichiro

    2012-01-01

    Worldwide growth of space communications has caused a rapid increase in the number of satellites operating in geostationary orbits, causing overcrowded orbits. This practical resource is designed to help professionals overcome this problem. This timely book provides a solid understanding of the use of radio interferometers for tracking and monitoring satellites in overcrowded environments. Practitioners learn the fundamentals of radio interferometer hardware, including antennas, receiving equipment, signal processing and phase detection, and measurement accuracies. This in-depth volume describ

  20. Radio Eska Lodz, Commercial Radio As a Local Radio

    OpenAIRE

    Szews, Przemysław

    2015-01-01

    The article discusses aspects of network-based local radio using the example of Radio Eska Lodz. The author responds to questions about whether a commercial network radio station can fulfill the functions of local radio and on what this locality is actually based. In this respect, Radio Eska Lodz is characterized as part of the most popular commercial radio network in Poland. The introduction focuses on the process of transformation that local radio stations are undergoing, along with its gen...

  1. Optimizing power efficiency in radio-over-fiber systems

    DEFF Research Database (Denmark)

    Koonen, A. M. J.; Popov, M.; Wessing, Henrik

    2013-01-01

    Fiber-fed radio pico-cells topologies can reduce the overall power consumption of wireless communication networks. Joint optimization of fiber and radio network parts yields an optimum number of pico-cells which minimizes power consumption.......Fiber-fed radio pico-cells topologies can reduce the overall power consumption of wireless communication networks. Joint optimization of fiber and radio network parts yields an optimum number of pico-cells which minimizes power consumption....

  2. K. C. Yeh: Radio Science Editor

    Science.gov (United States)

    Advances in satellite technology and computer science have had the greatest impact on radio science in the last quarter century, according to Kung Chie Yeh, the new editor of Radio Science. Yeh, whose term began July 1 (Eos, April 12, 1983, p. 137, February 22, 1983, p. 73), is a professor in the electrical engineering department at the University of Illinois at Urbana-Champaign.An international authority on ionospheric radio physics, Yeh also is known for his work on trans-ionospheric radio wave propagation as it affects earth-space communications and satellite navigation. Hehas been studying radio science for nearly 30 years.

  3. Emerging High-Frequency (HF) and Related Radio Communications Concepts for Enduring C(3)I Roles in a Nuclear War Environment: Critical Issues in Nuclear Weapons Effects on Propagation. (Sanitized)

    Science.gov (United States)

    1980-06-01

    System, EDL-M723, 1 September 1964. 10. R. W. Hendrick, Jr., Nuclear Detonation Degradation of Over-the-Horizon Radars G. E. TEMPO, 67 TEMPO- 8...specified mode structures (b) Raytracing techniques without limiting the mode structure (3) Noise model (a) Worldwide noise maps (b) Calculated noise...search Institute, Menlo Park, CA (March 1974), 21. G. H. Smith, "An Introduction to OTH Radar Performance in a Nuclear Environment P," DNA 3736T

  4. Radio Astronomy Explorer (RAE) 1 observations of terrestrial radio noise

    Science.gov (United States)

    Herman, J. R.; Caruso, J. A.

    1971-01-01

    Radio Astonomy Explorer (RAE) 1 data are analyzed to establish characteristics of HF terrestrial radio noise at an altitude of about 6000 km. Time and frequency variations in amplitude of the observed noise well above cosmic noise background are explained on the basis of temporal and spatial variations in ionospheric critical frequency coupled with those in noise source distributions. It is shown that terrestrial noise regularly breaks through the ionosphere and reaches RAE with magnitudes 15 or more db higher than cosmic noise background. Maximum terrestrial noise is observed when RAE is over the dark side of the Earth in the neighborhood of equatorial continental land masses where thunderstorms occur most frequently. The observed noise level is 30-40 db lower with RAE over oceans.

  5. 77 FR 66743 - Radio Broadcasting Services; Crowell, Knox City, Quanah, and Rule, TX

    Science.gov (United States)

    2012-11-07

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Crowell, Knox City, Quanah, and Rule, TX AGENCY... in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez... Communications Commission amends 47 CFR part 73 as follows: PART 73--RADIO BROADCAST SERVICES 0 1. The...

  6. Ionospheric heating with oblique HF waves

    Science.gov (United States)

    Field, Edward C., Jr.; Bloom, Ron M.

    1990-10-01

    Calculations of ionospheric electron density perturbations and ground-level signal changes produce by intense oblique high frequency (HF) transmitters are presented. This analysis considers radio field focusing at caustics, the consequent joule-heating of the surrounding plasma, heat conduction, diffusion, and recombination processes: these being the effects of a powerful oblique 'modifying' wave. It neglects whatever plasma instabilities might occur. Then effects on a secondary 'test' wave that is propagated along the same path as the first are investigated. Calculations predict ground-level field-strength reductions of several dB in the test wave for modifying waves having ERP in the 85 to 90 dBW range. These field-strength changes are similar in sign, magnitude, and location to ones measured in Soviet experiments. The results are sensitive to the model ionosphere assumed, so future experiments should employ the widest possible range of frequencies and propagation conditions. An effective power of 90 dBW seems to be a sort of threshold that, if exceeded, results in substantial rather than small signal changes. The conclusions are based solely on joule-heating and subsequent defocusing of waves passing through caustic regions.

  7. Energy and spectrum efficiency in rural areas based on cognitive radio technology

    CSIR Research Space (South Africa)

    Masonta, MT

    2009-09-01

    Full Text Available The rapid growth and development observed in wireless communications has resulted in the overcrowding of the radio spectrum used as a communication medium in wireless networks. In many countries, governmental agencies regulate the use of the radio...

  8. Low-cost approach for a software-defined radio based ground station receiver for CCSDS standard compliant S-band satellite communications

    Science.gov (United States)

    Boettcher, M. A.; Butt, B. M.; Klinkner, S.

    2016-10-01

    A major concern of a university satellite mission is to download the payload and the telemetry data from a satellite. While the ground station antennas are in general easy and with limited afford to procure, the receiving unit is most certainly not. The flexible and low-cost software-defined radio (SDR) transceiver "BladeRF" is used to receive the QPSK modulated and CCSDS compliant coded data of a satellite in the HAM radio S-band. The control software is based on the Open Source program GNU Radio, which also is used to perform CCSDS post processing of the binary bit stream. The test results show a good performance of the receiving system.

  9. Solar Radio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists monitor the structure of the solar corona, the outer most regions of the Sun's atmosphere, using radio waves (100?s of MHz to 10?s of GHz). Variations in...

  10. DARPA NetCentric radio demonstration

    Science.gov (United States)

    Stotts, Larry B.; Seidel, Scott; Krout, Tim; Kolodzy, Paul

    2007-04-01

    The objective of the DARPA Network Centric Radio System1 (NCRS) Program was to design, develop, integrate, and demonstrate the enabling communication technologies and system capabilities required to enable network centric warfare. NCRS is a First Generation Mobile, Ad Hoc Network (MANET) designed to enable ground and airborne vehicle based on-the-move and on-the-halt network centric connectivity. It demonstrated a gateway architecture that offers interoperability among various current, future, coalition and first responder communications radios, via the network, not the radio. This capability illustrated a new dimension for military communications interoperability.

  11. Impact of tropospheric scintillation in the Ku/K bands on the communications between two LEO satellites in a radio occultation geometry

    DEFF Research Database (Denmark)

    Martini, Enrica; Freni, A.; Facheris, L.

    2006-01-01

    A theoretical analysis of the impact of clear-air tropospheric scintillation on a radio occultation link between two low Earth orbit satellites in K- and Ku-bands is presented, with particular reference to differential approaches for the measure of the total content of water vapor. The troposphere...

  12. Environmentally friendly HF (DF) lasers

    Science.gov (United States)

    Apollonov, V. V.

    2016-08-01

    Dedicated to the 100th anniversary of the birth of Academician A M Prokhorov, this paper reviews the physics of self-sustained volume discharge without preionization—self-initiated volume discharge (SIVD)—in the working mixtures of non-chain hydrofluoride HF (deuterofluoride (DF)) lasers. The dynamics of SIVD in discharge gaps with different geometries is thoroughly described. The mechanisms for the restriction of current density in a diffuse channel in electric discharges in SF6 and SF6 based mixtures (which determines whether SIVD is possible) are proposed and analyzed using simple models. The most probable mechanisms are the electron impact dissociation of SF6 and other mixture components, electron-ion recombination and electron attachment to vibrationally excited SF6 molecules. Starting from a comparative analysis of the rate coefficients of these processes, it is shown that electron-ion recombination is capable of compensating for electron detachment from negative ions via electron impact. It is also established that SIVD is not only observed in SF6, but also in other strongly electronegative gases. The factors that determine the uniformity of the active medium in non-chain HF (DF) lasers are analyzed. Some special features of non-chain HF (DF) lasers with different apertures operating are carefully examined. Consideration is given to the problem of increasing the aperture and discharge volume of non-chain HF (DF) lasers. Based on our experimental results, the possibility of increasing the energy of such lasers to ~1 kJ and above is shown.

  13. ELF/VLF wave generation from the beating of two HF ionospheric heating sources

    Science.gov (United States)

    Cohen, M. B.; Moore, R. C.; Golkowski, M.; Lehtinen, N. G.

    2012-12-01

    It is well established that Extremely Low Frequency (ELF, 0.3-3 kHz) and Very Low Frequency (VLF, 3-30 kHz) radio waves can be generated via modulated High Frequency (HF, 3-10 MHz) heating of the lower ionosphere (60-100 km). The ionospheric absorption of HF power modifies the conductivity of the lower ionosphere, which in the presence of natural currents such as the auroral electrojet, creates an `antenna in the sky.' We utilize a theoretical model of the HF to ELF/VLF conversion and the ELF/VLF propagation, and calculate the amplitudes of the generated ELF/VLF waves when two HF heating waves, separated by the ELF/VLF frequency, are transmitted from two adjacent locations. The resulting ELF/VLF radiation pattern exhibits a strong directional dependence (as much as 15 dB) that depends on the physical spacing of the two HF sources. This beat wave source can produce signals 10-20 dB stronger than those generated using amplitude modulation, particularly for frequencies greater than 5-10 kHz. We evaluate recent suggestions that beating two HF waves generates ELF/VLF waves in the F-region (>150 km), and conclude that those experimental results may have misinterpreted, and can be explained strictly by the much more well established D region mechanism.

  14. Local control of cognitive radio networks

    NARCIS (Netherlands)

    Doerr, C.; Grunwald, D.; Sicker, D.C.

    2009-01-01

    In a network deployment, a cognitive radio will have to perform two fundamental tasks. First, each cognitive radio needs to optimize its internal operation, and second, it needs to derive a configuration that will enable and optimize communication with other nodes in the network. This latter require

  15. 47 CFR 32.2231 - Radio systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Radio systems. 32.2231 Section 32.2231 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2231 Radio systems. (a...

  16. Antenna Construction and Propagation of Radio Waves.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on antenna construction and propagation of radio waves is designed to provide communicators with instructions in the selection and/or construction of the proper antenna(s) for use with current field radio equipment. Introductory materials include…

  17. Artificial Ionization and UHF Radar Response Associated with HF Frequencies near Electron Gyro-Harmonics (Invited)

    Science.gov (United States)

    Watkins, B. J.; Fallen, C. T.; Secan, J. A.

    2013-12-01

    We present new results from O-mode ionospheric heating experiments at the HAARP facility in Alaska to demonstrate that the magnitude of artificial ionization production is critically dependent on the choice of HF frequency near gyro-harmonics. For O-mode heating in the lower F-region ionosphere, typically about 200 km altitude, artificial ionization enhancements are observed in the lower ionosphere (about 150 - 220 km) and also in the topside ionosphere above about 500 km. Lower ionosphere density enhancements are inferred from HF-enhanced ion and plasma-line signals observed with UHF radar. Upper ionospheric density enhancements have been observed with TEC (total electron content) experiments by monitoring satellite radio beacons where signal paths traverse the HF-modified ionosphere. Both density enhancements and corresponding upward plasma fluxes have also been observed in the upper ionosphere via in-situ satellite observations. The data presented focus mainly on observations near the third and fourth gyro-harmonics. The specific values of the height-dependent gyro-harmonics have been computed from a magnetic model of the field line through the HF heated volume. Experiments with several closely spaced HF frequencies around the gyro-harmonic frequency region show that the magnitude of the lower-ionosphere artificial ionization production maximizes for HF frequencies about 1.0 - 1.5 MHz above the gyro-harmonic frequency. The response is progressively larger as the HF frequency is increased in the frequency region near the gyro-harmonics. For HF frequencies that are initially greater than the gyro-harmonic value the UHF radar scattering cross-section is relatively small, and non-existent or very weak signals are observed; as the signal returns drop in altitude due to density enhancements the HF interaction region passes through lower altitudes where the HF frequency is less than the gyro-harmonic value, for these conditions the radar scattering cross-section is

  18. Communication Systems Analysis Laboratory (CSAL)

    Data.gov (United States)

    Federal Laboratory Consortium — CSAL conducts electronic warfare investigations of radio frequency communication systems with respect to current and emerging electronic warfare threats. CSAL uses...

  19. Distortion mitigation in cognitive radio receivers

    NARCIS (Netherlands)

    Mahrof, Dlovan Hoshiar

    2015-01-01

    The exponential increase of wireless communication increasingly leads to spectrum congestion. Attempts are being made to increase RF spectrum utilization efficiency by introducing Cognitive Radio (CR) concept. A CR tries to intelligently solve the congestion problem via Dynamic Spectrum Acce

  20. Radio astronomy

    CERN Document Server

    Alder, Berni

    1975-01-01

    Methods in Computational Physics, Volume 14: Radio Astronomy is devoted to the role of the digital computer both as a control device and as a calculator in addressing problems related to galactic radio noise. This volume contains four chapters and begins with a technical description of the hardware and the special data-handling problems of using radioheliography, with an emphasis on a selection of observational results obtained with the Culgoora radioheliograph and their significance to solar physics and to astrophysics in general. The subsequent chapter examines interstellar dispersion, i

  1. Can You Hear Us Now? Investigating the Effects of a Wireless Grid Social Radio Station on Collaboration and Communication in Fragile Populations

    Science.gov (United States)

    Chauncey, Sarah A.

    2012-01-01

    The ability to interact with peers and coworkers in online digital networks is essential in learning and business environments. Our digital participatory culture is based on communication in response to purposeful activity and is facilitated by information and communication technologies (ICT). Students with emotional, behavioral, and learning…

  2. Can You Hear Us Now? Investigating the Effects of a Wireless Grid Social Radio Station on Collaboration and Communication in Fragile Populations

    Science.gov (United States)

    Chauncey, Sarah A.

    2012-01-01

    The ability to interact with peers and coworkers in online digital networks is essential in learning and business environments. Our digital participatory culture is based on communication in response to purposeful activity and is facilitated by information and communication technologies (ICT). Students with emotional, behavioral, and learning…

  3. Performance Analysis of HF Band FB-MC-SS

    Energy Technology Data Exchange (ETDEWEB)

    Hussein Moradi; Stephen Andrew Laraway; Behrouz Farhang-Boroujeny

    2016-01-01

    Abstract—In a recent paper [1] the filter bank multicarrier spread spectrum (FB-MC-SS) waveform was proposed for wideband spread spectrum HF communications. A significant benefit of this waveform is robustness against narrow and partial band interference. Simulation results in [1] demonstrated good performance in a wideband HF channel over a wide range of conditions. In this paper we present a theoretical analysis of the bit error probably for this system. Our analysis tailors the results from [2] where BER performance was analyzed for maximum ration combining systems that accounted for correlation between subcarriers and channel estimation error. Equations are give for BER that closely match the simulated performance in most situations.

  4. Modeling and simulating of wireless communication system with GNU Radio and USRP%基于GNU Radio和USRP的无线通信系统建模仿真

    Institute of Scientific and Technical Information of China (English)

    杨宏; 孔耀晖; 茹晨光; 李珂; 潘赟

    2013-01-01

    To achieve rapid and accurate modeling and simulation for wireless communication system in complex wireless transmission environment,a software radio system consisting of GNU Radio and USRP is applied in this paper as a new model-ing and simulation method for wireless communication system. Its software characteristics and hardware framework are analyzed. A comparison experiment on link model bit error rate of MPSK modulation system working in the real channel and simulation channel was performed. A prototype of wireless video transmission system was realized based on the link module with the real wireless channel. Analysis and experiment results show that the new modeling and simulation method with software radio system has superiorities in rapid prototype implementation and capacity to bring the real wireless channel into system model to achieve more accurate simulation and analysis result. This method is applicable to the research and design of wireless communication sys-tems with customized requirements of complex transmission environment.%针对无线通信环境的复杂特性,为了实现无线通信系统快速准确的建模仿真,应用GNU Radio和USRP组成的软件无线电系统作为新的建模仿真方法。介绍并分析该方法的软件特性和硬件架构,进行MPSK调制系统在仿真信道和实际信道下链路模型的误码率对比实验,并在包含实际无线信道的链路模型基础上,设计并实现了一套无线视频流传输原型系统。分析和实验结果表明,新方法能够快速实现无线通信系统原型,将实际无线信道纳入系统模型中,从而获得更准确的仿真和分析结果。该方法适用于对通信协议标准及系统有定制化需求、针对传输环境复杂的无线通信系统研究开发。

  5. Radio frequency propagation made easy

    CERN Document Server

    Faruque, Saleh

    2015-01-01

    This book introduces Radio Frequency Propagation to a broad audience.  The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications.  The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  6. Public safety and cognitive radio

    NARCIS (Netherlands)

    Heskamp, Marnix; Schiphorst, Roel; Slump, Kees; Wyglinsk, Alexander M.; Nekovee, Maziar; Hou, Y. Thomas

    2009-01-01

    This book gives comprehensive and balanced coverage of the principles of cognitive radio communications, cognitive networks, and details of their implementation, including the latest developments in the standards and spectrum policy. Case studies, end-of-chapter questions, and descriptions of variou

  7. Radio frequency modulation made easy

    CERN Document Server

    Faruque, Saleh

    2017-01-01

    This book introduces Radio Frequency Modulation to a broad audience. The author blends theory and practice to bring readers up-to-date in key concepts, underlying principles and practical applications of wireless communications. The presentation is designed to be easily accessible, minimizing mathematics and maximizing visuals.

  8. Numerical modeling of HF skywave radiation from antennas in irregular terrain

    Energy Technology Data Exchange (ETDEWEB)

    Burke, G.J.

    1990-11-01

    The problem of computing the radiation pattern of an HF antenna sited in irregular terrain was investigated. The primary interest is in antennas for skywave communication, however ionospheric models were not considered. Several methods for modeling terrain effects are briefly reviewed. A geometrical optics model for arbitrary terrain is developed and results are compared with published results from solution of a Volterra integral equation for scattering by a Gaussian ridge. This report covers work on the first phase of a project for the US Navy to develop and apply models for terrain effects in HF communications involving skywave. 45 refs., 16 figs.

  9. Digitale radio

    NARCIS (Netherlands)

    Schiphorst, Roel; Zondervan, L.

    2007-01-01

    Als eerste in Europa heeft Nederland begin december 2006 de omschakeling van analoge naar digitale ethertelevisie gemaakt. Voor de analoge FM-radio is er ook een digitale variant, T-DAB. T-DAB staat voor 'Terrestrial Digital Audio Broadcasting'. Dit artikel gaat verder in op deze techniek en de veld

  10. Charge storage and tunneling mechanism of Ni nanocrystals embedded HfOx film

    Directory of Open Access Journals (Sweden)

    H. X. Zhu

    2016-05-01

    Full Text Available A nano-floating gate memory structure based on Ni nanocrystals (NCs embedded HfOx film is deposited by means of radio-frequency magnetron sputtering. Microstructure investigations reveal that self-organized Ni-NCs with diameters of 4-8 nm are well dispersed in amorphous HfOx matrix. Pt/Ni-NCs embedded HfOx/Si/Ag capacitor structures exhibit voltage-dependent capacitance-voltage hysteresis, and a maximum flat-band voltage shift of 1.5 V, corresponding to a charge storage density of 6.0 × 1012 electrons/cm2, is achieved. These capacitor memory cells exhibit good endurance characteristic up to 4 × 104 cycles and excellent retention performance of 105 s, fulfilling the requirements of next generation non-volatile memory devices. Schottky tunneling is proven to be responsible for electrons tunneling in these capacitors.

  11. Far-Field Testing Method of Spurious Emission Produced by HF RFID

    Directory of Open Access Journals (Sweden)

    Nikola Gvozdenovic

    2016-01-01

    Full Text Available We present measurements of spurious emission produced by high-frequency radio frequency identification (HF RFID using carrier frequency of 13.56 MHz. HF RFID tags produce unwanted emission due to rectification and more generally due to nonlinearity of analog front end. Depending on the conducting material of an HF RFID coil and surrounding dielectric material, the coil behaves as more or less good antenna on some harmonic frequencies. Exact characterization and analysis of unwanted emission is important from the security perspective as well as from the perspective of interference with other systems. Consequently we measured the harmonics produced in the integrated circuitry and characterized radiation properties of the antenna. Finally we present the measurements of the spurious emission performed in a Gigahertz Transverse Electromagnetic (GTEM cell.

  12. A thirty second isomer in Hf-171

    NARCIS (Netherlands)

    Campbell, P; Billowes, J; Cochrane, ECA; Cooke, JL; Cooper, TG; Dendooven, P; Evans, DE; Grant, IS; Griffith, JAR; Honkanen, A; Huhta, M; Oinonen, M; Pearson, MR; Penttila, H; Persson, B.L.; Richardson, DS; Tungate, G; Wheeler, PD; Zybert, L; Aysto, J

    1997-01-01

    An isomer has been detected in Hf-171 with a half-life of T-1/2 = 29.5(9) s. The state was populated in the Yb-170(alpha,3n)Hf-171m reaction at a beam energy of E-alpha = 50 MeV in an on-line ion guide isotope separator. The isomeric Hf-17lm(+) beam was extracted from the ion guide, mass-analysed an

  13. 78 FR 48626 - Private Land Mobile Radio Rules

    Science.gov (United States)

    2013-08-09

    ... COMMISSION 47 CFR Part 90 Private Land Mobile Radio Rules AGENCY: Federal Communications Commission. ACTION... regarding the certification and use of Terrestrial Trunked Radio (TETRA) equipment in response to a petition... Terrestrial Trunked Radio (TETRA) equipment. In response, we clarify that the rules adopted in the Report...

  14. Community Radio in Political Theory and Development Practice

    African Journals Online (AJOL)

    zeleza

    development problems, as part of development projects communication strategy, and ... community radio stations citizens and non-citizens can develop their political ..... Radio has the power to reach people in rural settings, people who may not ... Sandip Das notes that in India, radio reaches 90 percent of India's population.

  15. 77 FR 25112 - Radio Broadcasting Services; Centerville and Midway, TX

    Science.gov (United States)

    2012-04-27

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Centerville and Midway, TX AGENCY: Federal... filing procedures for comments, see 47 CFR 1.415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  16. 78 FR 73793 - Radio Broadcasting Services; Evart and Ludington, Michigan

    Science.gov (United States)

    2013-12-09

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Evart and Ludington, Michigan AGENCY: Federal... filing procedures for comments, see 47 CFR 1.415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio...

  17. 47 CFR 97.407 - Radio amateur civil emergency service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radio amateur civil emergency service. 97.407... SERVICES AMATEUR RADIO SERVICE Providing Emergency Communications § 97.407 Radio amateur civil emergency service. (a) No station may transmit in RACES unless it is an FCC-licensed primary, club, or...

  18. 47 CFR 13.211 - Commercial radio operator license examination.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Commercial radio operator license examination. 13.211 Section 13.211 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL RADIO OPERATORS Examination System § 13.211 Commercial radio operator license examination. (a) Each session...

  19. 47 CFR 13.5 - Licensed commercial radio operator required.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Licensed commercial radio operator required. 13.5 Section 13.5 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL COMMERCIAL RADIO OPERATORS General § 13.5 Licensed commercial radio operator required. Rules that require FCC...

  20. DBS Radio: Deathstar or Dud? Info. Packets No. 24.

    Science.gov (United States)

    Pizzi, Skip

    The Federal Communications Commission (FCC) has been progressing over the past 5 years toward the institution of Direct Broadcast Satellite Radio (DBS-R) which would institute a new type of radio service. The FCC refers to the service as Satellite DARS (Digital Audio Radio Service), and it would provide reliable, high-fidelity satellite-delivered…

  1. 78 FR 266 - Radio Broadcasting Services; Maysville, GA

    Science.gov (United States)

    2013-01-03

    ...-270; RM-11676; DA 12-2024] Radio Broadcasting Services; Maysville, GA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Appalachian Broadcasting... Review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio...

  2. 78 FR 36683 - Radio Broadcasting Services; Summit, Mississippi

    Science.gov (United States)

    2013-06-19

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Summit, Mississippi AGENCY: Federal Communications... Broadcasting, allots FM Channel 228A ] as a first local service at Summit, Mississippi. To accommodate that... U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting....

  3. 78 FR 21337 - Radio Broadcasting Services; Matagorda, TX

    Science.gov (United States)

    2013-04-10

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Matagorda, TX AGENCY: Federal Communications... filed by Tejas Broadcasting Ltd., LLP (``Petitioner''), licensee of FM Station KMJR, Channel 252C2, Odem....415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal...

  4. 75 FR 41123 - Radio Broadcasting Services; Gearhart, OR

    Science.gov (United States)

    2010-07-15

    ... COMMISSION 47 CFR Part 73 . Radio Broadcasting Services; Gearhart, OR AGENCY: Federal Communications... comment on a petition filed by Black Hills Broadcasting, L.P. proposing the allotment of FM Channel 243A... Radio, Radio broadcasting. For the reasons discussed in the preamble, the Federal...

  5. 75 FR 80013 - Radio Broadcasting Services; Jewett, TX

    Science.gov (United States)

    2010-12-21

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Jewett, TX AGENCY: Federal Communications Commission. ACTION: Proposed rule; dismissal. SUMMARY: At the petitioner's request, the Audio Division has...

  6. 78 FR 42700 - Radio Broadcasting Services; Matagorda, Texas

    Science.gov (United States)

    2013-07-17

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Matagorda, Texas AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Tejas Broadcasting Ltd., LLP... broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief, Audio Division, Media...

  7. 75 FR 71411 - Radio Broadcasting Services; Silverpeak, NV

    Science.gov (United States)

    2010-11-23

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Silverpeak, NV AGENCY: Federal Communications Commission. ACTION: Proposed rule; dismissal. SUMMARY: The Audio Division dismisses the petition for...

  8. 76 FR 79113 - Radio Broadcasting Services; Bastrop, LA

    Science.gov (United States)

    2011-12-21

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Bastrop, LA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Audio Division, at the request of Kenneth W. Diebel...

  9. 76 FR 43933 - Radio Broadcasting Services; Markham, TX

    Science.gov (United States)

    2011-07-22

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Markham, TX AGENCY: Federal Communications Commission. ACTION: Final rule; denial of petition for reconsideration. SUMMARY: The Audio Division has denied...

  10. 77 FR 2242 - Radio Broadcasting Services; Pike Road, AL

    Science.gov (United States)

    2012-01-17

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Pike Road, AL AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: This document requests comments on a petition for rule...

  11. White House Communications Agency (WHCA) Presidential Voice Communications Rack Mount System Mechanical Drawing Package

    Science.gov (United States)

    2015-12-01

    Harris , 117G, communications, White House Communications Agency 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18...used by WHCA. The customer desired to upgrade their comms equipment from Harris 117F radios to 117G radios. These radios offer a smaller package with...rack unit (9U) chassis that did not use a fiber optic modem and instead used direct radio frequency (RF) output from the Harris 117F radio. The

  12. GNU Based Security in Software Defined Radio

    Directory of Open Access Journals (Sweden)

    H. B. Bhadka

    2012-11-01

    Full Text Available Various new technologies are explored for radio communication toward the 21st century. Among them the technology of "software defined radio" attracts large attention. Software Defined Radio (SDR technology implements some of the functional modules of a radio system in software enabling highly flexible handsets. SDR devices may be reconfigured dynamically via the download of new software modules. Malicious or malfunctioning downloaded software present serious security risks to SDR devices and networks in which they operate. Together with the use of software downloading, future terminals will become a platform to support the deployment of yet unspecified services and applications.

  13. Equatorial ionospheric disturbance observed through a transequatorial HF propagation experiment

    Directory of Open Access Journals (Sweden)

    T. Maruyama

    2006-07-01

    Full Text Available A transequatorial radio-wave propagation experiment at shortwave frequencies (HF-TEP was done between Shepparton, Australia, and Oarai, Japan, using the radio broadcasting signals of Radio Australia. The receiving facility at Oarai was capable of direction finding based on the MUSIC (Multiple Signal Classification algorithm. The results were plotted in azimuth-time diagrams (AT plots. During the daytime, the propagation path was close to the great circle connecting Shepparton and Oarai, thus forming a single line in the AT plots. After sunset, off-great-circle paths, or satellite traces in the AT plot, often appeared abruptly to the west and gradually returned to the great circle direction. However, there were very few signals across the great circle to the east. The off-great-circle propagation was very similar to that previously reported and was attributed to reflection by an ionospheric structure near the equator. From the rate of change in the direction, we estimated the drift velocity of the structure to range mostly from 100 to 300 m/s eastward. Multiple instances of off-great-circle propagation with a quasi-periodicity were often observed and their spatial distance in the east-west direction was within the range of large-scale traveling ionospheric disturbances (LS-TIDs. Off-great-circle propagation events were frequently observed in the equinox seasons. Because there were many morphological similarities, the events were attributed to the onset of equatorial plasma bubbles.

  14. Military Mail Radio

    Directory of Open Access Journals (Sweden)

    Bîlbîie Răduţ

    2015-12-01

    Full Text Available Cultural and scientific personalities from the army, military experts and creators of the doctrine have collaborated with the radio from the beginnings of radiophony, the educational role of this new, persuasive communication channel being evident not only for Romania or the Romanian army but also for all the countries that had radiophony services. This happens in the context of the end of the crisis and the start of economic and social development, promoting culture, creating a solid class of peasants with a certain social status, in villages, together with the priest, teacher and gendarme, increasing of the number of subscriptions and development of the Romanian radiophony.

  15. Newnes communications technology handbook

    CERN Document Server

    Lewis, Geoff

    1994-01-01

    Newnes Communications Technology Handbook provides a discussion on different topics relevant to communications technology. The book is comprised of 39 chapters that tackle a wide variety of concern in communications technology. The coverage of the text includes technologies, such as analog digital communications systems, radio frequency receiver, and satellite systems. The book also discusses some methods and techniques used in communications technology, including mixer signal processing, modulation and demodulation, and spread spectrum techniques. The text will be of great use to engineers, t

  16. Artificial ducts caused by HF heating of the ionosphere by HAARP

    OpenAIRE

    Vartanyan, A.; Milikh, G. M.; Mishin, E.; Parrot, Michel; Galkin, I.; Reinisch, B; Huba, J.; Joyce, G.; Papadopoulos, K.

    2012-01-01

    International audience; We report on satellite observations of plasma density enhancements (ducts) in thetopside ionosphere during four HAARP/BRIOCHE campaigns during 2009–2010.Artificial ducts, caused by high-power HF radio wave injections from the HAARPtransmitter toward the magnetic zenith, are detected by the DEMETER and DMSPsatellites on a regular basis when there is a perceptible ionospheric F2 peak density.Overall, the plasma density enhancements detected between 0930 and 1230 LT varie...

  17. Artificial ducts caused by HF heating of the ionosphere by HAARP

    OpenAIRE

    Vartanyan, A.; Milikh, G. M.; E. Mishin; Parrot, Michel; Galkin, I.; B. Reinisch; Huba, J.; Joyce, G.; Papadopoulos, K.

    2012-01-01

    International audience; We report on satellite observations of plasma density enhancements (ducts) in thetopside ionosphere during four HAARP/BRIOCHE campaigns during 2009–2010.Artificial ducts, caused by high-power HF radio wave injections from the HAARPtransmitter toward the magnetic zenith, are detected by the DEMETER and DMSPsatellites on a regular basis when there is a perceptible ionospheric F2 peak density.Overall, the plasma density enhancements detected between 0930 and 1230 LT varie...

  18. Brief communication "A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (M=6.3 occurred on 6 April 2009"

    Directory of Open Access Journals (Sweden)

    T. Ligonzo

    2010-02-01

    Full Text Available We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009 an interruption of the broadcasting from the transmitter (RMC, France happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic defocusing is inexistent. Our doubts on this action are reported.

  19. The study of multilayers Fe/Hf and Ni/Hf by slow positron beam technique

    Science.gov (United States)

    Tashiro, Mutsumi; Nakajyo, Terunobu; Murashige, Yusuke; Koizumi, Tomoya; Kanazawa, Ikuzo; Komori, Fumio; Soe, We-Hyo; Yamamoto, Ryoichi; Ito, Yasuo

    1997-05-01

    The S-parameters versus the incident positron energy are measured in the Ni/Hf multilayer, thin Hf film, thin Fe film and the bilayer Fe/Hf. We have analyzed the change in vacancy-type defects in these multilayers and thin films with the deposition temperature in the MBE system.

  20. On Achievable Performance of Cognitive Radio Systems

    CERN Document Server

    Haddad, Majed; Hayar, Aawatif Menouni

    2007-01-01

    In this contribution, we investigate the idea of using cognitive radio to reuse locally unused spectrum to increase the total system capacity. We consider a multiband/wideband system in which the primary and cognitive users wish to communicate to different receivers, subject to mutual interference and assume that each user knows only his channel and the unused spectrum through adequate sensing. Under this scheme, a cognitive radio will listen to the channel and, if sensed idle, will transmit during the voids. Within this setting, we provide two simple methods for sensing the idle sub-bands over the total bandwidth. We impose the constraint that users successively transmit over available bands through proper water filling. For the first time, our study has quantified the achievable gain of using cognitive radio with respect to classical radio devices and derive the total spectral efficiency as well as the maximum number of possible pairwise communications of such a cognitive radio system. We finally show that ...

  1. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  2. The Radio JOVE Project - Shoestring Radio Astronomy

    Science.gov (United States)

    Thieman, J.; Flagg, R.; Greenman, W.; Higgins, C.; Reyes, F.; Sky, J.

    2010-01-01

    Radio JOVE is an education and outreach project intended to give students and other interested individuals hands-on experience in learning radio astronomy. They can do this through building a radio telescope from a relatively inexpensive kit that includes the parts for a receiver and an antenna as well as software for a computer chart recorder emulator (Radio Skypipe) and other reference materials

  3. Conception d'un crypto-système reconfigurable pour la radio logicielle sécurisée

    OpenAIRE

    Grand, Michael

    2011-01-01

    The research detailed in this document deal with the design and implementation of a hardware integrated circuit intended to be used as a cryptographic sub-system in secure software defined radios. Since the early 90's, radio systems have gradually evolved from traditional radio to software defined radio. Improvement of the software defined radio has enabled the integration of an increasing number of communication standards on a single radio device. The designer of a software defined radio fac...

  4. Calculating the probability of detecting radio signals from alien civilizations

    CERN Document Server

    Horvat, Marko

    2006-01-01

    Although it might not be self-evident, it is in fact entirely possible to calculate the probability of detecting alien radio signals by understanding what types of extraterrestrial radio emissions can be expected and what properties these emissions can have. Using the Drake equation as the obvious starting point, and logically identifying and enumerating constraints of interstellar radio communications can yield the probability of detecting a genuine alien radio signal.

  5. HF radiation emitted by chaotic leader processes

    Science.gov (United States)

    Mäkelä, J. S.; Edirisinghe, M.; Fernando, M.; Montaño, R.; Cooray, V.

    2007-04-01

    This paper presents direct measurements of narrowband 10 MHz HF radiation from so-called “chaotic leaders” associated with subsequent return strokes. Although the term is controversial and poorly defined, we find that more than 30% of subsequent strokes in close lightning flashes contain electric field characteristics that are best described as “chaotic”. In earlier studies, return strokes have consistently been observed to be the strongest sources of HF radiation, but the results for leader processes are less consistent. We also observe return strokes to be the main HF emitter, and the leaders before the first return stroke in a flash sequence also emit HF though somewhat less intensely. The leaders preceding subsequent strokes typically emit little or no HF radiation, whether they are dart or dart-stepped leaders. However, it was observed that the presence of a chaotic component increases the leader HF intensity dramatically Defining the HF intensity unequivocally can be problematic for processes like chaotic leaders which have a combination of continuous and impulsive phenomena. Two time-domain methods were used to measure the HF intensity, the peak energy and the RMS energy. In the frequency domain these correspond to the energy spectral density (ESD) and power spectral density (PSD), respectively. It was found that the methods are not necessarily compatible. Thus, it is suggested that to clarify future work, leader processes should be characterized by the PSD rather than the ESD.

  6. Synthesis and White-Light Emission of ZnO/HfO2: Eu Nanocables

    Directory of Open Access Journals (Sweden)

    Liu Lixin

    2010-01-01

    Full Text Available Abstract ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis.

  7. 电力光载无线宽带接入技术研究%Radio-on-fiber broadband access technology in power communication

    Institute of Scientific and Technical Information of China (English)

    许盛; 曾强; 易浩勇; 刘柱

    2011-01-01

    Combined with the fiber-optic communications and the wireless communication technologies ad-vantage,Rof communication is a good way to solve the problems of bandwidth flexibility security and the electromagnetic interference. With the construction of smart grid carry out, the communication demands of bandwidth, stability and reliability have been increasing, research the RoF technology,based on the EPON net-work,focusing on the system downlink transmission protocol,using the existing EPON network to get the wireless nodes together. The RoF could combine the advantages of fiber and wireless, and provide the air interface services for the end-users, meeting the needs of power communication, while reducing communication costs.The Practical application field testing of Hybrid-optical-wireless proves the feasibility of the technology's performance.%光载无线技术结合光纤通信和无线移动通信的技术优势,可以较好地解决带宽、灵活性和电磁干扰问题.随着我国智能电网建设的展开,对通信带宽、稳定性和接入可靠性的要求越来越高.研究基于电力EPON的光载无线宽带接入技术,重点是系统上下行传输协议.用现有的电力EPON网络汇聚无线节点,结合光和无线两者的优势,为终端用户提供空中接口服务,可以在满足电力通信需求的同时减少成本.通过现场实际应用测试证明了该技术的性能和可行性.

  8. HfS, Hyperfine Structure Fitting Tool

    CERN Document Server

    Estalella, Robert

    2016-01-01

    HfS is a tool to fit the hyperfine structure of spectral lines, with multiple velocity components. The HfS_nh3 procedures included in HfS fit simultaneously the hyperfine structure of the NH$_3$ (J,K)= (1,1) and (2,2) transitions, and perform a standard analysis to derive $T_\\mathrm{ex}$, NH$_3$ column density, $T_\\mathrm{rot}$, and $T_\\mathrm{k}$. HfS uses a Monte Carlo approach for fitting the line parameters. Especial attention is paid to the derivation of the parameter uncertainties. HfS includes procedures that make use of parallel computing for fitting spectra from a data cube.

  9. Sermon and surprise: The meaning of scheduling in broadcast radio history - and - CBC Radio 3: A disquieting revolution

    OpenAIRE

    Sahota, Anu

    2006-01-01

    Essay 1 : 'Sermon & Surprise' explores the importance of scheduling to radio's communicative uses. The essay argues that its capacity for continuous transmission and promotion of shared listening is unique to terrestrial radio. The strengths of traditional radio relative to contemporary on-demand audio media are explored. Early Canadian and British broadcasting policies and scheduling practices demonstrate how radio's programming conceits may innovatively accommodate broadcasting philosop...

  10. Radio-over-fiber as the enabler for joint processing of spatially separated radio signals

    OpenAIRE

    Monteiro P.; Pato S.; Pedro J.; Santos J.; Wake D.; Nkansah A.; Gomes N.; Lopez E.; Gameiro A

    2009-01-01

    An overview of the FUTON project is presented, with emphasis on the optical link design for radio-over-fiber communication and virtual-MIMO functionalities between multiple remote antenna units and a centralized processing site.

  11. 77 FR 16800 - Radio Broadcasting Services; Dermott, AR, and Cleveland, MS

    Science.gov (United States)

    2012-03-22

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Dermott, AR, and Cleveland, MS AGENCY: Federal... 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant... Commission requests comment on a petition filed by Delta Radio Network, LLC, proposing to amend the Table...

  12. 78 FR 27306 - Radio Broadcasting Services; Dermott, Arkansas, and Cleveland, Mississippi

    Science.gov (United States)

    2013-05-10

    ... COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Dermott, Arkansas, and Cleveland, Mississippi AGENCY... Delta Radio Network, LLC, substitutes FM Channel 224A for 289A at Dermott, Arkansas, and substitutes FM... CFR part 73 Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez,...

  13. Implementation and extension of a GNU-Radio RFID reader

    Science.gov (United States)

    Smietanka, G.; Brato, S.; Freudenberg, M.; Götze, J.

    2013-07-01

    The development of a flexible software defined RFID is discused. Commercial reader systems only allow a top level view on the communication and restrict the variation for many transmission parameters. Recently a software reader from the CGran project was proposed which uses the GNU Radio environment in combination with an USRP front end. Because most of the signal processing is done on a common host PC, this reader offers high flexibility, but also has several disadvantages. One of the main hardware limitations is the usage of only one separated antenna per transmit and receive path. Commercial readers usually use four antennas which are time multiplexed and can be used as transmitter and receiver. In this work a HF multiplexer for the USRP device is introduced. With this extension up to four transmit and receive antennas can be used in combination with the software reader. It is shown that the multiplexer achieves good read rates for a switching interval of 100 ms. Using this multiplexer the read range of the system decrease compared to the basic software reader, but distances over two meters can still be realized without additional hardware extensions.

  14. An Analysis of Marine Corps Beyond Line of Sight Wideband Satellite Communications Requirements

    Science.gov (United States)

    2010-09-01

    Network (SWAN) ............................................40 9. Tropo /Satellite Support Radio (TSSR) ............................................42...Service Tactical Communications Program TROPO ...tropospheric scatter TSSR..................................................tropospheric scatter ( TROPO )-satellite support radio TSST

  15. Radio and the Church – a Historical Glance

    Directory of Open Access Journals (Sweden)

    Carl-Mario Sultana

    2014-09-01

    Full Text Available Radio is a very powerful mass communication medium. In radio broadcasting, one can hear the echo of Christ’s words to his apostles in the missionary discourse: “You received without charge, give without charge...What you hear in whispers, proclaim from the house tops” (Mt 10,8b.27. Although the Church uses radio as a means to transmit the Good News of salvation, and we as human beings receive radio transmissions as a part of our daily life, we barely stop to think and reflect upon the underlying aspects of radio as a means of communication. In this paper, the Author endeavours to give a historical overview of what makes radio an important medium for evangelisation according to four key documents of the Church, while also studying the underlying theological positions found in these documents. These documents enable us to study radio as a broadcasting medium, highlighting the possible reactions of the Church to radio and how the Church changed its stance on radio over the years. The reason for focussing specifically on radio is for two particular reasons: from the very beginning, the Church has considered radio as a means for evangelising the masses. Notwithstanding this, what is going to be discussing in the paper can be equally applied to Television as a mass communication medium. Secondly, the Church took an active role in radio broadcasting by asking Guglielmo Marconi himself to construct the Vatican Radio in 1931. The documents of the Church also offer us a theology of radio as a mass communication medium, with unity, progress and evangelisation being the fundamental aspects. Church documents posit that not everything should be broadcasted over radio but only messages which bring about peace and unity.

  16. Wideband Parameters Analysis and Validation for Indoor radio Channel at 60/70/80GHz for Gigabit Wireless Communication employing Isotropic, Horn and Omni directional Antenna

    Directory of Open Access Journals (Sweden)

    E. Affum

    2013-07-01

    Full Text Available recently, applications of millimeter (mm waves for high-speed broadband wireless local area network communication systems in indoor environment are increasingly gaining recognition as it provides gigabit-speed wireless communications with carrier-class performances over distances of a mile or more due to spectrum availability and wider bandwidth requirements. Collectively referred to as E-Band, the millimeter wave wireless technology present the potential to offer bandwidth delivery comparable to that of fiber optic, but without the financial and logistic challenges of deploying fiber. This paper investigates the wideband parameters using the ray tracing technique for indoor propagation systems with rms delay spread for Omni-directional and Horn Antennas for Bent Tunnel at 80GHz. The results obtained were 2.03and 1.95 respectively, besides, the normalized received power with 0.55×?10?^8excess delay at 70GHz for Isotropic Antenna which was at 0.97.

  17. High-latitude propagation studies using a meridional chain of LF/MF/HF receivers

    Directory of Open Access Journals (Sweden)

    J. LaBelle

    2004-04-01

    Full Text Available For over a decade, Dartmouth College has operated programmable radio receivers at multiple high-latitude sites covering the frequency range 100-5000kHz with about a 1-s resolution. Besides detecting radio emissions of auroral origin, these receivers record characteristics of the ionospheric propagation of natural and man-made signals, documenting well-known effects, such as the diurnal variation in the propagation characteristics of short and long waves, and also revealing more subtle effects. For example, at auroral zone sites in equinoctial conditions, the amplitudes of distant transmissions on MF/HF frequencies are often enhanced by a few dB just before they fade away at dawn. The polarization and/or direction of the arrival of ionospherically propagating signals in the lower HF range (3-5MHz show a consistent variation between pre-midnight, post-midnight, and pre-dawn conditions. As is well known, magnetic storms and substorms dramatically affect ionospheric propagation; data from multiple stations spanning the invariant latitude range 67-79° reveal spatial patterns of propagation characteristics associated with magnetic storms and substorms. For example, in the hours preceding many isolated substorms, favorable propagation conditions occur at progressively lower latitudes as a function of time preceding the substorm onset. For some of these effects, explanations follow readily from elementary ionospheric physics, but understanding others requires further investigation.

    Key words. Magnetospheric physics (annual phenomena – Radio science (ionosphere propagation; radio-wave propagation6

  18. Morphology of hydroxyapatite coated nanotube surface of Ti-35Nb-xHf alloys for implant materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Un [Functional Coatings Group, Materials Processing Division, Korea Institute of Materials Science (KIMS), Changwon, Kyungnam (Korea, Republic of); Jeong, Yong-Hoon [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials and Research Center for Oral Disease Regulation of the Aged, Chosun University, Gwangju (Korea, Republic of); Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, 305 W. 12th Ave. Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials and Research Center for Oral Disease Regulation of the Aged, Chosun University, Gwangju (Korea, Republic of)

    2011-11-01

    The purpose of this research is to study the morphology of hydroxyapatite coated nanotube surface of Ti-35Nb-xHf for implant materials using various experiments. For this study, Ti-35Nb-xHf (x = 0, 3, 7 and 15 wt.%) alloys were prepared by arc melting and heat treated for 12 h at 1000 Degree-Sign C in an argon atmosphere and then water quenching. Nanotube formation on the Ti-35Nb-xHf alloys was achieved by anodizing in H{sub 3}PO{sub 4} electrolytes containing 0.8 wt.% NaF at room temperature. Anodization was carried out using an electrochemical method and all experiments were conducted at room temperature. Hydroxyapatite (HA) was deposited on the nanotubular Ti-35Nb-xHf alloys surface for the biomaterials by radio-frequency (RF) magnetron sputtering method. The morphologies of nanotubular and HA coated surface were characterized by X-ray diffractometer (XRD), optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). The wettability of HA coated surface was measured by contact angle goniometer. The microstructure of Ti-35Nb-xHf alloys was transformed needle-like to equiaxed structure with Hf content and {alpha} Double-Prime phase decreased, whereas {beta} phase increased as Hf content increased. HA coating surface was affected by microstructure of bulk and morphology of nanotube formation. In case of low Hf content, tip of nanotube formed at {beta} phase was coated with HA film, whereas {alpha} Double-Prime phase was not coated with HA film. In case of high Hf content, nanotube surface was coated uniformly with HA film. The wettability of HA coated nanotubular surface was higher than that of non coated samples.

  19. Channel Analysis and Estimation and Compensation of Doppler Shift in Underwater Acoustic Communication and Mitigation of IFI, ISI in Ultra-wideband Radio

    Science.gov (United States)

    Ahmed, Sadia

    Water occupies three fourth of earth's surface. The remaining one fourth is land. Although human habitats reside on land, there is no denying of the vital connection between land and water. The future sustainability of human species on this planet depends on wise utilization of all available resources, including that provided by the vast water world. Therefore, it is imperative to explore, understand, and define this massive, varying, and in many areas, unexplored water domain. The water domain exploration and data collection can be conducted using manned or unmanned vehicles, as allowed by the water environment. This dissertation addresses three of the key difficulties that occur during underwater acoustic communication among manned and/or unmanned vehicles and proposes feasible solutions to resolve those difficulties. The focus and the contributions of this research involve the following perspectives: 1) Representation of Underwater Acoustic Communication (UAC) Channels: Providing a comprehensive classification and representation of the underwater acoustic communication channel based on the channel environment. 2) Estimation and Compensation of Doppler Shift: Providing compensation algorithm to mitigate varying Doppler shift effect over subcarriers in UAC Orthogonal Frequency Division Multiplexing (OFDM) systems. 3) Mitigation of Inter-symbol Interference (ISI): Providing feasible solution to long delay spread causing ISI in Ultra-wideband channels.

  20. Spatial Identification of Passive Radio Frequency Identification Tags Using Software Defined Radios

    Science.gov (United States)

    2012-03-01

    of 56 MBytes per second [20]. All communications between the main board and GNU Radio on the host PC take place through this controller. More recent...Digital AGC and Data signal from the main board are both determined by the Python code generated by GNU Radio on the host PC. This local oscillator signal...running Ubuntu 10.10 and GNU Radio , a USRP1 SDR with a Flex 900 daughter card and two Alien 9611-CR antennas. The GNU Radio installation has been

  1. Software Radio Sampling Rate Selection, Design and Synchronization

    CERN Document Server

    Venosa, Elettra; Palmieri, Francesco A N

    2012-01-01

    Software Radio represents the future of communication devices. By moving a radio's hardware functionalities into software, SWR promises to change the communication devices creating radios that, built on DSP based hardware platforms, are multiservice, multiband, reconfigurable and reprogrammable. This book describes the design of Software Radio (SWR). Rather than providing an overview of digital signal processing and communications, this book focuses on topics which are crucial in the design and development of a SWR, explaining them in a very simple, yet precise manner, giving simulation results that confirm the effectiveness of the proposed design.  Readers will gain in-depth knowledge of key issues so they can actually implement a SWR.  Specifically the book addresses the following issues: proper low-sampling rate selection in the multi-band received signal scenario, architecture design for both software radio receiver and transmitter devices and radio synchronization. Addresses very precisely the most imp...

  2. Miniature EVA Software Defined Radio

    Science.gov (United States)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  3. Measuring the drinking behaviour of individual pigs housed in group using radio frequency identification (RFID)

    OpenAIRE

    2016-01-01

    Changes in the drinking behaviour of pigs may indicate health, welfare or productivity problems. Automated monitoring and analysis of drinking behaviour could allow problems to be detected, thus improving farm productivity. A high frequency radio frequency identification (HF RFID) system was designed to register the drinking behaviour of individual pigs. HF RFID antennas were placed around four nipple drinkers and connected to a reader via a multiplexer. A total of 55 growing-finishing pigs w...

  4. 一种新的基于椭圆球面波函数的非正弦短波通信的均衡方案%A New Equalizer for Non-sinusodial HF Communication Based on Prolate Spheroidal Wave Function

    Institute of Scientific and Technical Information of China (English)

    潘耀宗; 孙小东; 钟佩琳; 刘传辉; 王红星

    2012-01-01

    针对基于椭圆球面波函数(Prolate Spheroidal Wave Function,PSWF)的非正弦通信技术在短波频段内受到多径时延,引起码间串扰导致系统可靠性下降的问题,在分析信道特性对基于PSWF非正弦调制信号影响和非正弦通信的特殊性的基础上,通过对均衡思路的分析,设计了一种新的均衡方案.此方案首先将码间串扰对正交性的影响转化为对判决数据信号质量的影响.进而,针对每一路判决数据信号采取均衡措施,提高判决数据的质量.最后,依据判决准则进行判决.仿真结果表明这种新的均衡方案是有效的,在给定的仿真条件下,信噪比为24 dB时,误码率约从10-2改善到10-3;针对PSWF脉冲两种不同的生成方法(单波道脉冲生成方法和多波道脉冲生成方法)生成脉冲组的特性,在基本均衡方案的基础上提出了参数共享式均衡和分组参数共享式均衡两种方法,并在最后给出了仿真结果,证明了这两种方法的有效性.%The multipath effects of the HF channel make the BER of non-sinusodial HF communication based on Prolate Spheroidal Wave Function (PSWF) increasing. An new equalizer scheme is proposed on the base of analysising the factors reducing the quality of decision dates and the particularity of the non-sinusodial communication systerm based on PSWF. This scheme transfer the effects of ISI to the quality of the decision date signals, and taking measures to equilibrium each path of decision date signals to improve its quality. Finally, the disicion will be made according to the judgement criterion. The results of the simulations show that the new equalizer is effective, and the BER can be reducing from 10-2 to 10-3, when the SNR is 24 dB. For the group of different characteristics of PSWF pulses which come from different pulse generating methods including constructing method of PSWF based on single-channel and constructing method of PSWF based on multi-channel, parameters

  5. HF Transverse Segmentation and Tagging Jet Capability

    CERN Document Server

    Doroshkevich, E A; Kuleshov, Sergey

    1998-01-01

    So called tagging jets and pile-up were simulated for the optimisation of the HF segmentation. The energy resolution, angular resolution and efficiency of jet reconstruction are defined for different calorimeter segmentation.

  6. Collisional quenching of highly rotationally excited HF

    CERN Document Server

    Yang, Benhui; Forrey, R C; Stancil, P C; Balakrishnan, N

    2015-01-01

    Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H$_2$ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach. The calculation of state-to-state rotational quenching cross sections for HF due to He with initial rotational levels up to $j=20$ were performed for kinetic energies from 10$^{-5}$ to 15000...

  7. Cognitive Radio for Smart Grid with Security Considerations

    Directory of Open Access Journals (Sweden)

    Khaled Shuaib

    2016-04-01

    Full Text Available In this paper, we investigate how Cognitive Radio as a means of communication can be utilized to serve a smart grid deployment end to end, from a home area network to power generation. We show how Cognitive Radio can be mapped to integrate the possible different communication networks within a smart grid large scale deployment. In addition, various applications in smart grid are defined and discussed showing how Cognitive Radio can be used to fulfill their communication requirements. Moreover, information security issues pertained to the use of Cognitive Radio in a smart grid environment at different levels and layers are discussed and mitigation techniques are suggested. Finally, the well-known Role-Based Access Control (RBAC is integrated with the Cognitive Radio part of a smart grid communication network to protect against unauthorized access to customer’s data and to the network at large.

  8. Microhardness evaluation alloys Hf-Si-B; Avaliacao de microdureza de ligas Hf-Si-B

    Energy Technology Data Exchange (ETDEWEB)

    Gigolotti, Joao Carlos Janio; Costa, Eliane Fernandes Brasil [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Nunes, Carlos Angelo; Rocha, Elisa Gombio; Coelho, Gilberto Carvalho, E-mail: carlosjanio@uol.com.br, E-mail: eliane-costabrasi@hotmail.com, E-mail: cnunes@demar.eel.usp.br, E-mail: elisarocha@alunos.eel.usp.br, E-mail: coelho@demar.eel.usp.br [Universidade de Sao Paulo (USP), Lorena, SP (Brazil)

    2014-08-15

    The technological advance has generated increasing demand for materials that can be used under high temperature, what includes intermetallic MR-Si-B (MR = refractory metal) alloys with multiphase structures, that can also be applied in oxide environments. Thus, this work had for objective the micro hardness study of the Hf-Si-B system alloys, heat treated at 1600 deg C, in the Hf rich region. Hf-Si-B alloys had been produced with blades of Hf (min. 99.8%), Si (min. 99.998%) and B (min. 99.5%), in the voltaic arc furnace and heat treated at 1600 deg C under argon atmosphere. The relationship of the phases had been previously identified by X-ray diffraction and contrast in backscattered electron imaging mode. The alloys had their hardness analyzed by method Vickers (micro hardness) with load of 0.05 kgf and 0.2 kgf and application time of 20 s. The results, obtained from the arithmetic mean of measurements for each alloy on the heterogeneous region, showed a mean hardness of 11.08 GPA, with small coefficient of variation of 3.8%. The borides HfB2 (19.34 GPa) e HfB - 11.76 GPa, showed the hardness higher than the silicides Hf2Si (8.57 GPa), Hf5Si3 (9.63 GPa), Hf3Si2 (11.66 GPa), Hf5Si4 (10.00 GPa), HfSi (10.02 GPa) e HfSi2 (8.61 GPa). (author)

  9. Cognitive Radio Networks From Theory to Practice

    CERN Document Server

    Khattab, Ahmed; Bayoumi, Magdy

    2013-01-01

    This book describes a communication paradigm that could shape the future of wireless communication networks, Opportunistic Spectrum Access (OSA) in Cognitive Radio Networks (CRN).  While several theoretical OSA approaches have been proposed, they are challenged by the practical limitations of cognitive radios: the key enabling technology of OSA.  This book presents an unprecedented formulation of the OSA problem in CNR that takes into account the practical limitations encountered due to existing technologies. Based on such a problem formulation, this book presents a framework and protocol details implementing the analytically-optimized solution of this problem. Unlike the state-of-the-art of CRN implementations that typically target software define radios which are not suitable for real systems, this book describes the implementation of distributed OSA, using practical radio transceiver technologies. It provides a thorough characterization of the gains available to theoretical OSA approaches if the practica...

  10. Robustness of digitally modulated signal features against variation in HF noise model

    Directory of Open Access Journals (Sweden)

    Shoaib Mobien

    2011-01-01

    Full Text Available Abstract High frequency (HF band has both military and civilian uses. It can be used either as a primary or backup communication link. Automatic modulation classification (AMC is of an utmost importance in this band for the purpose of communications monitoring; e.g., signal intelligence and spectrum management. A widely used method for AMC is based on pattern recognition (PR. Such a method has two main steps: feature extraction and classification. The first step is generally performed in the presence of channel noise. Recent studies show that HF noise could be modeled by Gaussian or bi-kappa distributions, depending on day-time. Therefore, it is anticipated that change in noise model will have impact on features extraction stage. In this article, we investigate the robustness of well known digitally modulated signal features against variation in HF noise. Specifically, we consider temporal time domain (TTD features, higher order cumulants (HOC, and wavelet based features. In addition, we propose new features extracted from the constellation diagram and evaluate their robustness against the change in noise model. This study is targeting 2PSK, 4PSK, 8PSK, 16QAM, 32QAM, and 64QAM modulations, as they are commonly used in HF communications.

  11. The crisis of the radio producing

    Directory of Open Access Journals (Sweden)

    Dr. Raúl Garcés

    2007-09-01

    Full Text Available In a media world highly influenced by new technologies revolution and the increasing impact of television, speeches on radio are frequently polarized: in one side, some scholars argue radio belongs to the past and it is no longer able of attracting younger audiences. In the other, lay those who predict long life to radio as a source of alternative and communitarian communication experiences. The author reviews the arguments that sustain both perspectives and emphasizes the need of renovating radio producing with audacious and creative formulas. At the same time, he discusses some of the challenges Cuban radio has ahead to attract new audiences, when television and printed press are recovering from the economic crack the Island suffered after Eastern European socialism disappeared.

  12. Intervehicle Communication Research – Communication Scenarios

    Directory of Open Access Journals (Sweden)

    Šarūnas Stanaitis

    2011-03-01

    Full Text Available Recently intervehicle communications are attracting much attention from industry and academia. Upcoming standard for intervehicle communication IEEE 802.11p, known as Wireless Access in Vehicular Environments (WAVE, is still in its draft stage, but already coming into final standardization phase. Problematic, regarding mobile WAVE nodes, are described in several articles, simulations prepared and experiments done. But most of these works do not consider possible maximal communication load. This paper presents intervehicle communication scenario in respect to radio communications, mobility and other aspects of vehicular environments.Article in English

  13. Kajian implementasi radio siaran digital di Indonesia [Study of digital radio broadcasting implementation in Indonesia

    Directory of Open Access Journals (Sweden)

    Amry Daulat Gultom

    2015-12-01

    Full Text Available Peraturan Menteri Komunikasi dan Informatika RI nomor 21 tahun 2009 tentang  Standar Penyiaran Digital Untuk Penyiaran Radio pada Pita VHF di Indonesia menyatakan bahwa dalam rangka mengatasi permasalahan penggunaan frekuensi VHF Band II untuk penyiaran radio FM yang tidak sesuai dengan rencana induk, serta tidak terpenuhinya permohonan untuk penggunaan kanal frekuensi dari masyarakat, maka perlu dicarikan saluran siaran alternatif dengan menggunakan sistem penyiaran radio digital standard DAB Family. Hingga saat ini belum ada perkembangan berarti terkait implementasinya, sehingga perlu dilakukan penelitian untuk mengetahui potensi radio siaran digital, kesiapan dari sisi pemerintah, operator, dan masyarakat, dan kendala yang dihadapi serta merumuskan strategi yang akan digunakan mengatasinya. Metode analisis yang digunakan adalah SWOT dan TOWS kualitatif dari data wawancara dan studi literatur. Hasil penelitian menunjukkan bahwa pihak stasiun radio sudah siap terhadap digitalisasi radio siaran, pihak pemerintah belum begitu siap karena belum adanya regulasi pendukung Permen Kominfo tentang standard radio digital, dan masyarakat juga belum siap karena kurangnya sosialisasi dan masih susah didapatkannya perangkat penerima siaran radio digital. Pengintegrasian penerima siaran radio digital pada kendaraan bermotor roda empat dan telepon genggam yang baru dapat meningkatkan keberadaan perangkat penerima siaran radio digital.*****The Minister of Communication and Information Regulation number 21 of 2009 on Digital Broadcasting Standards for VHF Band Radio Broadcasting in Indonesia stated that in order to overcome the problems of VHF Band II frequency utilization for FM radio broadcasting that is not in accordance with the master plan, as well as non-fulfillment of the request for frequency channels utilization of the society, neeed to find alternative broadcast channel by DAB Family digital radio broadcasting system. Until now there has no

  14. 47 CFR 101.603 - Permissible communications.

    Science.gov (United States)

    2010-10-01

    ... transmit their own communications, including the transmission of their products and information services.... In addition, Specialized Mobile Radio (SMR) licensees reclassified by the Commission as...

  15. Structural and electrical properties of metal ferroelectric insulator semiconductor structure of Al/SrBi2Ta2O9/HfO2/Si using HfO2 as buffer layer

    Science.gov (United States)

    Roy, A.; Dhar, A.; Bhattacharya, D.; Ray, S. K.

    2008-05-01

    Ferroelectric SrBi2Ta2O9 (SBT) thin films have been deposited by the radio-frequency magnetron sputtering technique on bare p-Si as well as on HfO2 insulating buffer p-Si. XRD patterns revealed the formation of a well-crystallized SBT perovskite thin film on the HfO2 buffer layer. The electrical properties of the metal-ferroelectric-insulator-semiconductor (MFIS) structure were characterized by varying thicknesses of the HfO2 layer. The MFIS structure exhibits a maximum clockwise C-V memory window of 1.60 V when the thickness of the HfO2 layer was 12 nm with a lower leakage current density of 6.20 × 10-7 A cm-2 at a positive applied voltage of 7 V. However, the memory window reaches a maximum value of 0.7 V at a bias voltage of ±5 and then decreases due to charge injection in the case of the insulating buffer layer thickness of 3 nm. The density of oxide trapped charges at/near the buffer layer-ferroelectric interface is studied by the voltage stress method. Capacitance-voltage (C-V) and leakage current density (J-V) characteristics of the Al/SBT/HfO2/Si(1 0 0) capacitor indicate that the introduction of the HfO2 buffer layer prevents interfacial diffusion between the SBT thin film and the Si substrate effectively and improves the interface quality. Furthermore, the Al/SBT/HfO2/Si structures exhibit excellent retention characteristics, the high and low capacitance values clearly distinguishable for over 1 h and 30 min. This shows that the proposed Al/SrBi2Ta2O9/HfO2/Si structure is ideally suitable for high performance ferroelectric memories.

  16. Application of mesh network radios to UGS

    Science.gov (United States)

    Calcutt, Wade; Jones, Barry; Roeder, Brent

    2008-04-01

    During the past five years McQ has been actively pursuing integrating and applying wireless mesh network radios as a communications solution for unattended ground sensor (UGS) systems. This effort has been rewarded with limited levels of success and has ultimately resulted in a corporate position regarding the use of mesh network radios for UGS systems. A discussion into the background of the effort, the challenges of implementing commercial off-the-shelf (COTS) mesh radios with UGSs, the tradeoffs involved, and an overview of the future direction is presented.

  17. Communication Jamming Taxonomy based on Software-Defined Radio%基于软件可定义无线电的通信干扰新分类方法

    Institute of Scientific and Technical Information of China (English)

    秦伟; 王可人

    2016-01-01

    随着软件可定义无线电技术在无线通信中的广泛应用,传统电子战中的干扰与网络攻击之间的区别变得模糊。为了更好地区分通信干扰与网络攻击,分析了一种基于软件可定义无线电的通信干扰分类方法。与以往通过信号物理参数对干扰进行分类不同的是,该方法主要通过干扰方所拥有的先验信息和干扰方反应的能力来进行分类。最后,讨论已有的干扰技术在所提出的分类方法中的所属类别。%With the wide application of software defined-radio technology in wireless networks, the distinction of between jamming in traditional electronic warfare and wireless cybersecurity attack become fairly hazy. In order to differentiate communication jammer from cybersecurity attack, a jammer taxonomy for classification of communication jammers is proposed. In contrast to the traditional jammer categorization via physical parameter of the signal, the proposed method implements classification via the a priori information possessed by and reaction capacity of the jammer. Finally, the jamming techniques in literatures and their classification in the proposed classification system are discussed in this paper.

  18. Communication devices for network-hopping communications and methods of network-hopping communications

    Science.gov (United States)

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  19. Radio Science Measurements with Suppressed Carrier

    Science.gov (United States)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  20. Implementing Software Defined Radio

    CERN Document Server

    Grayver, Eugene

    2013-01-01

    Software Defined Radio makes wireless communications easier, more efficient, and more reliable. This book bridges the gap between academic research and practical implementation. When beginning a project, practicing engineers, technical managers, and graduate students can save countless hours by considering the concepts presented in these pages. The author covers the myriad options and trade-offs available when selecting an appropriate hardware architecture. As demonstrated here, the choice between hardware- and software-centric architecture can mean the difference between meeting an aggressive schedule and bogging down in endless design iterations. Because of the author’s experience overseeing dozens of failed and successful developments, he is able to present many real-life examples. Some of the key concepts covered are: Choosing the right architecture for the market – laboratory, military, or commercial Hardware platforms – FPGAs, GPPs, specialized and hybrid devices Standardization efforts to ens...