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1
Bracht, Roger, Jeff Dimsdle, Dave Rich e Frank Smith. "RADIO FREQUENCY OVERVIEW OF THE HIGH EXPLOSIVE RADIO TELEMETRY PROJECT". International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607352.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaHigh explosive radio telemetry (HERT) is a project that is being developed jointly by Los Alamos National Laboratory and AlliedSignal FM&T. The ultimate goal is to develop a small, modular telemetry system capable of high-speed detection of explosive events, with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data, from a high-speed missile trajectory, is a very challenging opportunity. All captured data must be transmitted in less than 20 microseconds of time duration. This requires a high bits/Hertz microwave telemetry modulation code to insure transmission of the data within the limited time interval available.
2
Blackard, Kenneth Lee. "Measurements and models of radio frequency impulsive noise inside buildings". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08182009-040318/.
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3
Gendron, Paul John. "A comparison of digital beacon receiver frequency estimators". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-09292009-020307/.
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4
Bax, Walter T. "Modulation and frequency synthesis for wireless digital radio". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ48341.pdf.
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5
Bax, Walter T. (Walter Timothy) Carleton University Dissertation Engineering Electronics. "Modulation and frequency synthesis for wireless digital radio". Ottawa, 1999.
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6
Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications". Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/2493.
Testo completoAbstract (sommario):
Due to constraints on spectrum availability and transmitter power, both bandwidth and power efficient communication techniques are desirable for mobile radio. Continuous phase modulated (CPM) signals have gained attention because of their attractive power spectra (Steele, 1992). It has been shown that the trellis coded modulation (TCM) schemes could provide better bit error rate performances compared to the uncoded schemes (Ungerboeck, 1982). Therefore, the combination of TCM which improves error probability and CPM signals which yield low spectral occupancy is expected to provide good coding and modulation over bandwidth and power limited channels such as the one encountered in mobile radio communications.In this research, a Trellis Coded Modulation (TCM) scheme, which combines convolutional coding and partial response Continuous Phase Modulation (CPM) such as Gaussian Minimum Shift Keying (GMSK), is investigated. Also, this study concentrates on the use of rate-half convolutional codes, and GMSK (B(subscript)0T=0.3). The latter has been adopted in the Global System for Mobile Communications (GSM) system.Appropriate codes are selected assuming Maximum Likelihood Sequence Detection (MLSD) based on the Viterbi algorithm using an extensive computer search. The bit-error-rate (BER) performances of the selected trellis coded GMSK schemes are theoretically evaluated in the presence of additive white Gaussian noise (AWGN) and frequency-flat fading. In the case of fading, the analysis is simplified to assume only amplitude-fading, and without considering the effect of fading on the phase of the received signal.Computer simulations are used to evaluate the BER performances of the proposed trellis coded GMSK schemes in the presence of AWGN and practical impairments, such as sample timing offset and carrier phase errors. Coding gains of up to 2.2dB at a BER of 10(subscript)-3 are obtained under ideal sample timing and carrier recovery conditions. This has been achieved without increasing the receiver complexity based on the number of states in the Viterbi decoder, compared to the uncoded GMSK scheme. Furthermore, these coded schemes are more tolerant to sample timing and carrier phase impairments.Also, the BER performances of the proposed trellis coded GMSK schemes have been extensively investigated by computer simulations for frequency-flat and frequency-selective fading channels. In the case of frequency-selective fading, the Viterbi decoding is made adaptive to cater for the channel impulse response variations with time. With this adaptive receiver, the irreducible BERs of the coded scheme is found to be lower than that of the uncoded. Performance improvements are obtained with a trellis coded GMSK scheme using a constraint length 2 code with a Viterbi decoder of 16 states compared to the 128 states required for the uncoded scheme. Further, the coded scheme has shown less sensitivity to carrier phase errors, compared to the uncoded.
7
Bracht, Roger. "RADIO FREQUENCY PATH CHARACTERIZATION FOR WIDE BAND QUADRATURE AMPLITUDE MODULATION". International Foundation for Telemetering, 1998. http://hdl.handle.net/10150/607351.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, CaliforniaRemote, high speed, high explosive wave front monitoring requires very high bandwidth telemetry to allow transmission of diagnostic data before the explosion destroys the sensor system itself. The main motivation for this study is that no known existing implementation of this sort has been applied to realistic weapons environments. These facts have prompted the research and gathering of data that can be used to extrapolate towards finding the best modulation method for this application. In addition to research of similar existing analysis and testing operations, data was recently captured from a Joint Test Assembly (JTA) Air Launched Cruise Missile (ALCM) flight.
8
Davis, Kyle. "Radio frequency photonic in-phase and quadrature-phase vector modulation". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50354.
Testo completoAbstract (sommario):
The focus of this thesis is to investigate the implementation of Radio Frequency (RF) In-Phase and Quadrature-Phase (I/Q) vector modulation through the use of modern photonic components and sub-systems which offer extremely wide RF intrinsic bandwidths. All-electronic vector modulators suffer from frequency coverage limitations and amplitude and phase instability due to components such as phase shifters and variable gain controllers operating at or near 100\% bandwidth. In stark contrast, once an RF signal has been modulated onto an optical carrier, the percent bandwidth of the RF to carrier is typically less than 0.01\% percent.
The fundamental mechanisms and basic electronic and photonic components needed to achieve vector modulation is introduced first. The primary electrical component required in most architectures is the 90° RF hybrid coupler, which is required to generate the RF I and Q terms. The two primary photonic building blocks, aside from the laser, electro-optic modulator and demodulator, are Mach-Zehnder Modulators (MZM) and Variable Optical Attenuators (VOA). Through the utilization of these components, multiple past architectures are explored and multiple new architectures are designed simulated.
For each architecture, there is a discussion on the practical implementation. Considerations such as system complexity, integration, and sensitivity to unwanted environmental stimuli are taken into account with potential solutions to alleviate these risks. In closing, the noise figure and its impact on Spur-Free Dynamic Range (SFDR) for a basic RF photonic link is derived to provide a system-level figure of merit that can be used, in most RF applications, to determine the overall performance utility current and future designs.
9
Caldera, Manora K. "Combined coding and modulation in frequency-selective mobile communications". Curtin University of Technology, School of Electrical and Computer Engineering, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=9820.
Testo completoAbstract (sommario):
Due to constraints on spectrum availability and transmitter power, both bandwidth and power efficient communication techniques are desirable for mobile radio. Continuous phase modulated (CPM) signals have gained attention because of their attractive power spectra (Steele, 1992). It has been shown that the trellis coded modulation (TCM) schemes could provide better bit error rate performances compared to the uncoded schemes (Ungerboeck, 1982). Therefore, the combination of TCM which improves error probability and CPM signals which yield low spectral occupancy is expected to provide good coding and modulation over bandwidth and power limited channels such as the one encountered in mobile radio communications.In this research, a Trellis Coded Modulation (TCM) scheme, which combines convolutional coding and partial response Continuous Phase Modulation (CPM) such as Gaussian Minimum Shift Keying (GMSK), is investigated. Also, this study concentrates on the use of rate-half convolutional codes, and GMSK (B(subscript)0T=0.3). The latter has been adopted in the Global System for Mobile Communications (GSM) system.Appropriate codes are selected assuming Maximum Likelihood Sequence Detection (MLSD) based on the Viterbi algorithm using an extensive computer search. The bit-error-rate (BER) performances of the selected trellis coded GMSK schemes are theoretically evaluated in the presence of additive white Gaussian noise (AWGN) and frequency-flat fading. In the case of fading, the analysis is simplified to assume only amplitude-fading, and without considering the effect of fading on the phase of the received signal.Computer simulations are used to evaluate the BER performances of the proposed trellis coded GMSK schemes in the presence of AWGN and practical impairments, such as sample timing offset and carrier phase errors. Coding gains of up to 2.2dB at a BER of 10(subscript)-3 ++are obtained under ideal sample timing and carrier recovery conditions. This has been achieved without increasing the receiver complexity based on the number of states in the Viterbi decoder, compared to the uncoded GMSK scheme. Furthermore, these coded schemes are more tolerant to sample timing and carrier phase impairments.Also, the BER performances of the proposed trellis coded GMSK schemes have been extensively investigated by computer simulations for frequency-flat and frequency-selective fading channels. In the case of frequency-selective fading, the Viterbi decoding is made adaptive to cater for the channel impulse response variations with time. With this adaptive receiver, the irreducible BERs of the coded scheme is found to be lower than that of the uncoded. Performance improvements are obtained with a trellis coded GMSK scheme using a constraint length 2 code with a Viterbi decoder of 16 states compared to the 128 states required for the uncoded scheme. Further, the coded scheme has shown less sensitivity to carrier phase errors, compared to the uncoded.
10
Ng, Man-hung. "Bandwidth-efficient pilot-symbol-aided techniques for fading estimation in multipath fading channels". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22582174.
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Franco, Marcelo Jorge Herczfeld Peter R. "Wideband digital predistortion linearization of radio frequency power amplifiers with memory /". Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/485.
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12
Geisinger, Nathan P. "Classification of digital modulation schemes using linear and nonlinear classifiers". Thesis, Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Mar/10Mar%5FGeisinger.pdf.
Testo completoAbstract (sommario):
Thesis (Electrical Engineer and M.S. in Electrical Engineering)--Naval Postgraduate School, March 2010.Thesis Advisor(s): Fargues, Monique P. ; Cristi, Roberto ; Robertson, Ralph C. "March 2010." Description based on title screen as viewed on .April 27, 2010. Author(s) subject terms: Blind Modulation Classification, Cumulants, Principal Component Analysis, Linear Discriminant Analysis, Kernel-based functions. Includes bibliographical references (p. 211-212). Also available in print.
13
Pratt, Jason. "A HARDWARE PLATFORM FOR COGNITIVE RADIO". International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604472.
Testo completoAbstract (sommario):
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaCognitive radio is a reasonably new branch of research aimed at more fully utilizing the RF spectrum. This is accomplished by allowing wireless communication systems to dynamically choose a frequency band, and a modulation technique, based on the current state of the RF spectrum as perceived by the cognitive radio network. This paper will give a brief introduction of cognitive radio networks, and describe a hardware platform designed at the IFT/UMR Telemetry Learning Center. The test-bed will accommodate future research into cognitive networks, by allowing the user to dynamically change both its carrier frequency and modulation technique through software. A general description of the design of the platform is provided.
14
Ndovi, Lusungu. "Benefits to processor load for quadrature baseband versus radio frequency demodulation algorithms". Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1946.
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15
Shin, Hong-Sup. "Analysis of the probability of error in frequency hopping multiple access system /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5868.
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16
Lin, Chun-Ching. "Demodulation of Narrowband Radio Frequency Signals by Aliasing Sampling". PDXScholar, 1996. https://pdxscholar.library.pdx.edu/open_access_etds/5286.
Testo completoAbstract (sommario):
The objective of this thesis is to study the demodulation of narrowband radio frequency signals by aliasing sampling in order to reduce the sampling rate. The spectrum can be recreated at the lower frequency position by aliasing sampling. However, if the sampling rate is deviated from the desired one, error will occur. The sensitivity to the frequency error of aliasing sampling is studied. One main reason of the deviation of the sampling rate is the frequency drifting of the local oscillator. Being able to compensate the oscillator drifting errors inexpensively, automatic frequency control (AFC) loops are important at receivers. Two major digital AFC algorithms are studied. One is the Phase method AFC, and the other is the Magnitude method AFC. Study indicates that both methods perform almost equally well. One adaptive AFC algorithm is also proposed. The scheme of the adaptive AFC algorithm is to use Upper-bound and Lower-bound techniques to squeeze the frequency errors. It is shown that the adaptive AFC algorithm can achieve up to 20 dB average signal-to-noise power ratio over the Magnitude method AFC under a noisy environment.
17
Chen, Chih-Hung. "CMOS RF front-end design of a very narrowband transceiver with 0.18[micrometers]". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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18
Heath, Mark Richard. "Investigation of envelope-shaped digital frequency modulation and its application to personal radio systems". Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277193.
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19
Skuse, Barry. "Spectral aspects of a wideband frequency modulation mobile radio system employing time-compression multiplexing". Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760559.
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20
Peng, Song, Zhang XiaoLin, Cao Xue e Qi Xia. "THE APPLICATION OF DIGITAL DEMODULATION TECHNIQUE FOR FREQUENCY MODULATION SIGNAL IN TELEMETRY RECEIVER". International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/604956.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, CaliforniaCombined with an example of digital telemetry receiver design, this paper mainly discusses the application of software radio in telemetry receiver. The paper begins with an introduction of applying high efficiency digital filter and math analysis in quadrature digital frequency modulation and demodulation to digital frequency conversion technique. Next, Simulink/Matlab is used to simulate digital telemetry receiver. The method of simulation, analysis and calculation of performance and result of simulation are all available. In the end, the paper discusses digital telemetry receiver design and implement by making use of software radio technique, the circuits apply HSP50214 chip of Intersil Co., CPLD implements of Altera Co. and PC Bus. The sample is an expansion card for personal computer. Result of test, performance of the receiver and conclusion are given out, which show fine performance of receiver and can be apply to practice. The lever of this technology has reached first class in the world.
21
Akos, Dennis M. "A hybrid modulation for the VHF aeronautical channels". Ohio : Ohio University, 1992. http://www.ohiolink.edu/etd/view.cgi?ohiou1171473826.
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22
吳萬雄 e Man-hung Ng. "Bandwidth-efficient pilot-symbol-aided techniques for fading estimation in multipath fading channels". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242212.
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23
Song, Liying Tugnait Jitendra K. "Channel estimation and equalization for doubly-selective channels using basis expansion models". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Electrical_and_Computer_Engineering/Dissertation/Song_Liying_29.pdf.
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24
Cirineo, Tony, e Bob Troublefield. "STANDARD INTEROPERABLE DATALINK SYSTEM, ENGINEERING DEVELOPMENT MODEL". International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/608398.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, NevadaThis paper describes an Engineering Development Model (EDM) for the Standard Interoperable Datalink System (SIDS). This EDM represents an attempt to design and build a programmable system that can be used to test and evaluate various aspects of a modern digital datalink. First, an investigation was started of commercial wireless components and standards that could be used to construct the SIDS datalink. This investigation lead to the construction of an engineering developmental model. This model presently consists of wire wrap and prototype circuits that implement many aspects of a modern digital datalink.
25
Pattichis, Marios Stephanou. "AM-FM transforms with applications /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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26
Giles, Timothy C. "On the design of HF radio modems /". Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phg4724.pdf.
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Thesis (Ph. D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996?Copies of author's previously published articles inserted. Includes bibliographical references (leaves 118-126).
27
Sistanizadeh, Mohammad K. "Weak narrow-band signal detection in multivariate non-gaussian clutter". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71187.
Testo completoAbstract (sommario):
This dissertation is concerned with the development and performance analysis of non-linear receivers for detection of weak narrow-band signals in multivariate non-Gaussian clutter. The novelty of the detection scheme lies in the utilization of both the complex measurement and the multivariate non-Gaussian character of the clutter. Two clutter models are developed based on the available partial information. Model (I) is based on the a priori knowledge of the first-order density, correlation structure of the amplitude, and the circular symmetric assumption of the in-phase and quadrature phase components. Model (II) is based on the first-order in-phase and quadrature phase densities and the complex correlation structure. These models completely specify a multivariate complex nonGaussian density and can be used for clutter generation.
A class of optimum non-linear receiver structures based on weak signal level, canonically known as Locally Optimum Detectors (LOD) are derived under clutter Model (I). This can be considered to be a generalization of the LOD for the independent and identically distributed (i.i.d) clutter. The detectors utilize complex measurements and their structures depend on whether the underlying hypothesis testing model is real or complex.
The performance of each of the proposed detector structures, based on the concept of Efficacy, is formulated. Then, the performance of the detectors are evaluated with respect to a reference detector using Asymptotic Relative Efficiency (ARE) criterion. Numerical evaluation of the performance expression is carried out for constant signal in Weibull distribution for various density parameters. Simulation results indicate that the performance of the developed detectors, based on ARE, is superior to (i.i.d) LOD detector and matched filter.
Finally, the sensitivity of the detector performance to parameter variation of the structural non-linearities is investigated.Ph. D.
28
Xiao, Haiqiao. "Design of Radio-Frequency Filters and Oscillators in Deep-Submicron CMOS Technology". PDXScholar, 2008. https://pdxscholar.library.pdx.edu/open_access_etds/5233.
Testo completoAbstract (sommario):
Radio-frequency filters and oscillators are widely used in wireless communication and high-speed digital systems, and they are mostly built on passive integrated inductors, which occupy a relative large silicon area. This research attempted to implement filters and oscillators operating at 1-5 GHz using transistors only, to reduce the circuits’ area. The filters and oscillators are designed using active inductors, based on the gyrator principle; they are fabricated in standard digital CMOS technology to be compatible with logic circuits and further lower the cost. To obtain the highest operating frequency, only parasitic capacitors were used.
Two new active-inductor circuits are derived from this research, labeled allNMOS and all-NMOS-II. The all-NMOS active inductor was used to design high-Q bandpass filters and oscillators, which were fabricated in TSMC’s 0.18-µm digital CMOS process. The highest center frequency measured was 5.7 GHz at 0.20-µm gate length and the maximum repeatably measured Q was 665. 2.4-GHz circuits were also designed and fabricated in 0.40-µm gate length. The all-NMOS-II circuit has superior linearity and signal fidelity, which are robust against process and temperature variations, due to its novel structure. It was used in signal drivers and will be fabricated in commercial products.
Small-signal analysis was conducted for each of the active-inductor, filter and oscillator circuits, and the calculated performance matches those from simulations. The noise performance of the active inductor, active-inductor filter and oscillator was also analyzed and the calculated results agree with simulations. The difference between simulation and measured results is about 10% due to modeling and parasitic extraction error.
The all-NMOS active-inductor circuit was granted a US patent. The US patent for all-NMOS-II circuit is pending. This research generated three conference papers and two journal papers.
29
Krasňanský, Milan. "Radar Signal Processing for Radio Altimeter". Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-363816.
Testo completoAbstract (sommario):
Táto diplomová práca sa zaoberá návrhom a implementáciou algoritmu pre spracovaniu signálu z radaru využívajúceho frekvenčne modulovanú kontinuálnu vlnu. Cieľom je implementácia algoritmu, ktorý by bol dostatočne rýchly (výpočet v reálnom čase na cieľovej platforme) a dostatočne presný pre použitie v rádiovýškomere v ľahkom lietadle so zameraním na použitie počas pristávacieho manévru. Hlavnou metódou spracovania signálu, použitou v implementácii, je Diskrétna Fourierova transformácia. Vytvorený algoritmus bol otestovaný na reálnych letových dátach a pre pristávací manéver dosiahol uspokojivé výsledky.
30
Padilla, Marc Anthony. "FM Demodulators in Software-Defined Radio Using FPGAs with Rapid Prototyping". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2718.
Testo completoAbstract (sommario):
With the advent of software-defined radio, many radio applications have and are currently being designed for FPGAs, due to their high performance and reconfigurability. Invariably, "legacy" waveforms, such as FM, will need to be supported in such systems. A challenge that comes with programming FPGAs is the increased design and implementation time over conventional software programming. In this thesis, three FM demodulator techniques are implemented and compared in an FPGA. Two techniques are found to have similar SNR performance while having very different FPGA implementation characteristics. Library based design is explored for demodulators to increase FPGA design productivity. A block library is created and verified by use in tested demodulator designs. Two design tools that aim to increase design productivity in FPGAs, Ogre and HMFlow, are also examined and used to implement FM demodulators in a PCM/FM receiver design. Ogre leverages the demodulator block library, along with accompanying metadata, to decrease design time significantly. Design performance is not sacrificed when using Ogre. HMFlow, which relies on finer-grained blocks, reuses block implementation data to speed up implementation of the full design. The implementation of the HMFlow demodulator design is sped up by 3x but, when compared with the standard flow, produces an implementation with a reduced maximum clock rate (about 1/2) and with slightly more resources (about 6%). When comparing Ogre with HMFlow, the coarser-grained blocks of Ogre provide a more efficient design experience than that of HMFlow.
31
Papich, William J. "THE USE OF TELEMETRY IN AN ELECTROMAGNETIC TEST ENVIRONMENT". International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/607292.
Testo completoAbstract (sommario):
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaThe U.S. Army Redstone Technical Test Center (RTTC) uses telemetry as a vital part of its data acquisition and analysis for electromagnetic environmental effects developmental testing of U.S. Army weapon systems. Testing in an electromagnetic environment poses several unique challenges. These challenges have resulted in the development of highly customized telemetry and data acquisition systems. This paper discusses the design and integration of past and current telemetry needs to incorporate real-time or near real-time simulations or scene generations into the testing process.
32
Ajaz, Haroon. "Study of fade and inter-fade durations in Ku- and Ka- band frequencies using OLYMPUS satellite beacons". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12042009-020112/.
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Laster, Jeff D. "Frequency scaling of rain attenuation on satellite links in the Ku/Ka-bands using OLYMPUS satellite data". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06162009-063211/.
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34
Boström, Henrik. "An FPGA implementation of a digital FM modulator". Thesis, Linköpings universitet, Elektroniksystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70241.
Testo completoAbstract (sommario):
The increase in speed and density of programmable logic devices such as Field Programmable Gate Arrays (FPGA) enables ever more complex designs to be constructed within a short time frame. The flexibility of a programmable device eases the integration of a design with a wide variety of components on a single chip. Since Frequency Modulation (FM) is an analog modulation scheme, performing it in the digital domain introduces new challenges. The details of these challenges and how to deal with them are also explained. This thesis presents the design of a digital stereo FM modulator including necessary signal processing, such as filtering, waveform generation, stereo multiplexing etc. The solution is comprised of code written in Very high speed integrated circuit Hardware Description Language (VHDL) and a selection of free Intellectual Property (IP)-blocks and is intended for implementation on a Xilinx FPGA. The focus of the thesis lies on area efficiency and a number of suggestions are given to maximize the number of channels that can be modulated using a single FPGA chip. An estimation of how many channels that can be modulated usingthe provided FPGA, Xilinx XC6SXL100T, is also presented.
35
Lou, Shuzuo. "Design of CMOS RF low-noise amplifiers and mixer for wireless applications /". View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20LOU.
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36
Cui, Xian. "Efficient radio frequency power amplifiers for wireless communications". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1195652135.
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Flowers, Bryse Austin. "Adversarial RFML: Evading Deep Learning Enabled Signal Classification". Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/91987.
Testo completoAbstract (sommario):
Deep learning has become an ubiquitous part of research in all fields, including wireless communications. Researchers have shown the ability to leverage deep neural networks (DNNs) that operate on raw in-phase and quadrature samples, termed Radio Frequency Machine Learning (RFML), to synthesize new waveforms, control radio resources, as well as detect and classify signals. While there are numerous advantages to RFML, this thesis answers the question "is it secure?" DNNs have been shown, in other applications such as Computer Vision (CV), to be vulnerable to what are known as adversarial evasion attacks, which consist of corrupting an underlying example with a small, intelligently crafted, perturbation that causes a DNN to misclassify the example. This thesis develops the first threat model that encompasses the unique adversarial goals and capabilities that are present in RFML. Attacks that occur with direct digital access to the RFML classifier are differentiated from physical attacks that must propagate over-the-air (OTA) and are thus subject to impairments due to the wireless channel or inaccuracies in the signal detection stage. This thesis first finds that RFML systems are vulnerable to current adversarial evasion attacks using the well known Fast Gradient Sign Method originally developed for CV applications. However, these current adversarial evasion attacks do not account for the underlying communications and therefore the adversarial advantage is limited because the signal quickly becomes unintelligible. In order to envision new threats, this thesis goes on to develop a new adversarial evasion attack that takes into account the underlying communications and wireless channel models in order to create adversarial evasion attacks with more intelligible underlying communications that generalize to OTA attacks.Master of Science
Deep learning is beginning to permeate many commercial products and is being included in prototypes for next generation wireless communications devices. This technology can provide huge breakthroughs in autonomy; however, it is not sufficient to study the effectiveness of deep learning in an idealized laboratory environment, the real world is often harsh and/or adversarial. Therefore, it is important to know how, and when, these deep learning enabled devices will fail in the presence of bad actors before they are deployed in high risk environments, such as battlefields or connected autonomous vehicle communications. This thesis studies a small subset of the security vulnerabilities of deep learning enabled wireless communications devices by attempting to evade deep learning enabled signal classification by an eavesdropper while maintaining effective wireless communications with a cooperative receiver. The primary goal of this thesis is to define the threats to, and identify the current vulnerabilities of, deep learning enabled signal classification systems, because a system can only be secured once its vulnerabilities are known.
38
Erdem, Erem. "Digital Modulation Recognition". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611281/index.pdf.
Testo completoAbstract (sommario):
In this thesis work, automatic recognition algorithms for digital modulated signals are surveyed.
Feature extraction and classification algorithm stages are the main parts of a modulation recognition system. Performance of the modulation recognition system mainly depends on the prior knowledge of some of the signal parameters, selection of the key features and classification algorithm selection.
Unfortunately, most of the features require some of the signal parameters such as carrier frequency, pulse shape, time of arrival, initial phase, symbol rate, signal to noise ratio, to be known or to be extracted. Thus, in this thesis, features which do not require prior knowledge of the signal parameters, such as the number of the peaks in the envelope histogram and the locations of these peaks, the number of peaks in the frequency histogram, higher order moments of the signal are considered. Particularly, symbol rate and signal to noise ratio estimation methods are surveyed. A method based on the cyclostationarity analysis is used for symbol rate estimation and a method based on the eigenvector decomposition is used for the estimation of signal to noise ratio. Also, estimated signal to noise ratio is used to improve the performance of the classification algorithm.
Two methods are proposed for modulation recognition:
1) Decision tree based method
2) Bayesian based classification method
A method to estimate the symbol rate and carrier frequency offset of minimum-shift keying (MSK) signal is also investigated.
39
Hussaini, Abubakar S. "Energy efficient radio frequency system design for mobile WiMax applications. Modelling, optimisation and measurement of radio frequency power amplifier covering WiMax bandwidth based on the combination of class AB, class B, and C operations". Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5749.
Testo completoAbstract (sommario):
In today´s digital world, information and communication technology accounts for 3%
and 2% of the global power consumption and CO2 emissions respectively. This
alarming figure is on an upward trend, as future telecommunications systems and
handsets will become even more power hungry since new services with higher
bandwidth requirements emerge as part of the so called ¿future internet¿ paradigm. In
addition, the mobile handset industry is tightly coupled to the consumer need for more
sophisticated handsets with greater battery lifetime. If we cannot make any significant
step to reducing the energy gap between the power hungry requirements of future
handsets, and what battery technology can deliver, then market penetration for 4G
handsets can be at risk. Therefore, energy conservation must be a design objective at the
forefront of any system design from the network layer, to the physical and the
microelectronic counterparts. In fact, the energy distribution of a handset device is
dominated by the energy consumption of the RF hardware, and in particular the power
amplifier design. Power amplifier design is a traditional topic that addresses the design
challenge of how to obtain a trade-off between linearity and efficiency in order to avoid
the introduction of signal distortion, whilst making best use of the available power
resources for amplification. However, the present work goes beyond this by
investigating a new line of amplifiers that address the green initiatives, namely green
power amplifiers. This research work explores how to use the Doherty technique to
promote efficiency enhancement and thus energy saving. Five different topologies of
RF power amplifiers have been designed with custom-made signal splitters. The design
core of the Doherty technique is based on the combination of a class B, class AB and a
class C power amplifier working in synergy; which includes 90-degree 2-way power
splitter at the input, quarter wavelength transformer at the output, and a new output
power combiner. The frequency range for the amplifiers was designed to operate in the
3.4 - 3.6 GHz frequency band of Europe mobile WiMAX. The experimental results
show that 30dBm output power can be achieved with 67% power added efficiency
(PAE) for the user terminal, and 45dBm with 66% power added efficiency (PAE) for
base stations which marks a 14% and 11% respective improvement over current stateof-
the-art, while meeting the power output requirements for mobile WiMAX
applications.
40
Xu, Changting. "Investigation of Modulation Methods to Synthesize High Performance Resonator-Based RF MEMS Components". Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1135.
Testo completoAbstract (sommario):
The growing demand for wireless communication systems is driving the integration of radio frequency (RF) front-ends on the same chip with multi-band functionality and higher spectral efficiency. Microelectromechanical systems (MEMS) have an overarching applicability to RF communications and are critical components in facilitating this integration process. Among a variety of RF MEMS devices, piezoelectric MEMS resonators have sparked significant research and commercial interest for use in oscillators, filters, and duplexers. Compared to their bulky quartz crystal and surface acoustic wave (SAW) counterparts, MEMS resonators exhibit impressive advantages of compact size, lower production cost, lower power consumption, and higher level of integration with CMOS fabrication processes. One of the promising piezoelectric MEMS resonator technologies is the aluminum nitride (AlN) contour mode resonator (CMR). On one hand, AlN is chemically stable and offers superior acoustic properties such as large stiffness and low loss. Furthermore, CMRs offer low motional resistance over a broad range of frequencies (few MHZ to GHz), which are lithographically-definable on the same silicon substrates. To date, RF MEMS resonators (include CMRs) have been extensively studied; however, one aspect that was not thoroughly investigated is how to modulate/tune their equivalent parameters to enhance their performance in oscillators and duplexers. The goal of this thesis is to investigate various modulation methods to improve the thermal stability of the resonator, its “effective” quality factor when used in an oscillator, and build completely novel non-reciprocal components. Broadly defined, modulation refers to the exertion of a modifying or controlling influence on something, herein specifically, the resonator admittance. In this thesis, three categories of modulation methods are investigated: thermal modulation, force modulation, and external electronic modulation. Firstly, the AlN CMR’s center frequency can be tunned by the applied thermal power to the resonator body. The resonator temperature is kept constant (for example, 90 °C) via a temperature sensor and feedback control such that the center frequency is stable over the whole operation temperature range of interest (e.g. –35 to 85 °C). The maximum power consumption to sustain the maximum temperature difference (120 ºC in this thesis) between resonator and ambient is reduced to a value as low as 353 μW – the lowest ever reported for any MEMS device. These results were attained while simultaneously maintaining a high quality factor (up to 4450 at 220 MHz device). The feedback control was implemented by either analog circuits or via a microprocessor. The analog feedback control, which innovatively utilized a dummy resistor to compensate for temperature gradients, resulted in a total power consumption of 3.8 mW and a frequency stability of 100 ppm over 120 ºC. As for the digital compensation, artificial neural network algorithm was employed to facilitate faster calibration of look-up tables for multiple frequencies. This method attained a frequency stability of 14 ppm over 120 ºC. The second modulation method explored in this thesis is based on the use of an effective external force to enhance the 3-dB quality factor of AlN CMRs and improve the phase noise performance of resonator-based oscillators. The force modulation method was embodied in a two-port device, where one of the two ports is used as a one-port resonator and the other is driven by an external signal to effectively apply an external force to the first port. Through this technique, the quality factor of the resonator was boosted by 140 times (up to 150,000) and the phase noise of the corresponding oscillator realized using the resonator was reduced by 10 dBc/Hz. Lastly, a novel magnetic-free electrical circulator topology that facilitates the development of in-band full duplexers (IBFD) for simultaneous transmit and receive (STAR) is proposed and modeled. Fundamentally, a linear time-invariant (LTI) filter network parametrically modulated via a switching matrix is used to break the reciprocity of the filter. The developed model accurately predicts the circulator behavior and shows very good agreement with the experimental results for a 21.4 MHz circulators built with MiniCircuit filter and switch components. Furthermore, a high frequency (1.1 GHz) circulator was synthesized based on AlN MEMS bandpass filters and CMOS RF switches, hence showing a compact approach that can be used in handheld devices. The modulation frequency and duty cycle are optimized so that the circulator can provide up to 15 dB of isolation over the filter bandwidth while good power transfer between the other two ports is maintained. The demonstrated device is expected to intrinsically offer low noise and high linearity. The combination of the first two modulation methods facilitates the implementation of monolithic, temperature-stable, ultra-low noise, multi-frequency oscillator banks. The third modulation technique that was investigated sets the path for the development of CMOS-compatible in-band full duplexers for simultaneous transmit and receive and thus facilitates the efficient utilization of the electromagnetic spectrum. With the aid of all these three modulation approaches, the author believes that a fully integrated, multi-frequency, spectrum-efficient transceiver is enabled for next-generation wireless communications.
41
Hussaini, Abubakar Sadiq. "Energy efficient radio frequency system design for mobile WiMax applications : modelling, optimisation and measurement of radio frequency power amplifier covering WiMax bandwidth based on the combination of class AB, class B, and C operations". Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5749.
Testo completoAbstract (sommario):
In today's digital world, information and communication technology accounts for 3% and 2% of the global power consumption and CO2 emissions respectively. This alarming figure is on an upward trend, as future telecommunications systems and handsets will become even more power hungry since new services with higher bandwidth requirements emerge as part of the so called 'future internet' paradigm. In addition, the mobile handset industry is tightly coupled to the consumer need for more sophisticated handsets with greater battery lifetime. If we cannot make any significant step to reducing the energy gap between the power hungry requirements of future handsets, and what battery technology can deliver, then market penetration for 4G handsets can be at risk. Therefore, energy conservation must be a design objective at the forefront of any system design from the network layer, to the physical and the microelectronic counterparts. In fact, the energy distribution of a handset device is dominated by the energy consumption of the RF hardware, and in particular the power amplifier design. Power amplifier design is a traditional topic that addresses the design challenge of how to obtain a trade-off between linearity and efficiency in order to avoid the introduction of signal distortion, whilst making best use of the available power resources for amplification. However, the present work goes beyond this by investigating a new line of amplifiers that address the green initiatives, namely green power amplifiers. This research work explores how to use the Doherty technique to promote efficiency enhancement and thus energy saving. Five different topologies of RF power amplifiers have been designed with custom-made signal splitters. The design core of the Doherty technique is based on the combination of a class B, class AB and a class C power amplifier working in synergy; which includes 90-degree 2-way power splitter at the input, quarter wavelength transformer at the output, and a new output power combiner. The frequency range for the amplifiers was designed to operate in the 3.4 - 3.6 GHz frequency band of Europe mobile WiMAX. The experimental results show that 30dBm output power can be achieved with 67% power added efficiency (PAE) for the user terminal, and 45dBm with 66% power added efficiency (PAE) for base stations which marks a 14% and 11% respective improvement over current stateof- the-art, while meeting the power output requirements for mobile WiMAX applications.
42
Lu, Kan P. "Surface modulation of fluoropolymers for the improvement of adhesion : O₂-CF₄-Ar radio frequency plasma modification of poly (tetrafluoroethylene) /". Online version of thesis, 1994. http://hdl.handle.net/1850/11696.
Testo completo
43
Moore, Megan O. 'Neal. "One Size Does Not Fit All: Optimizing Sequence Length with Recurrent Neural Networks for Spectrum Sensing". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104050.
Testo completoAbstract (sommario):
With the increase in spectrum congestion, intelligent spectrum sensing systems have become more important than ever before. In the field of Radio Frequency Machine Learning (RFML), techniques like deep neural networks and reinforcement learning have been used to develop more complex spectrum sensing systems that are not reliant on expert features. Architectures like Convolutional Neural Networks (CNN) and Recurrent Neural Networks (RNN) have shown great promise for applications like automated modulation classification, signal detection, and specific emitter ID. Research in these areas has primarily focused on "one size fits all" networks that assume a fixed signal length in both training and inference. However, since some signals are more complex than others, due to channel conditions, transmitter/receiver effects, etc., being able to dynamically utilize just enough of the received symbols to make a reliable decision allows for more efficient decision making in applications such as electronic warfare and dynamic spectrum sharing. Additionally, the operator may want to get to the quickest possible decision.
Recurrent neural networks have been shown to outperform other architectures when processing temporally correlated data, such as from wireless communication signals. However, compared to other architectures, such as CNNs, RNNs can suffer from drastically longer training and evaluation times due to their inherent sample-by-sample data processing. While traditional usage of both of these architectures typically assumes a fixed observation interval during both training and testing, the sample-by-sample processing capabilities of recurrent neural networks opens the door for "decoupling" these intervals. This is invaluable in real-world applications due to the relaxation of the typical requirement of a fixed time duration of the signals of interest. This work illustrates the benefits and considerations needed when "decoupling" these observation intervals for spectrum sensing applications. In particular, this work shows that, intuitively, recurrent neural networks can be leveraged to process less data (i.e. shorter observation intervals) for simpler inputs (less complicated signal types or channel conditions). Less intuitively, this works shows that the "decoupling" is dependent on appropriate training to avoid bias and insure generalization.Master of Science
With the increase in spectrum congestion, intelligent spectrum sensing systems have become more important than ever before. In the field of Radio Frequency Machine Learning (RFML), techniques like deep neural networks and reinforcement learning have been used to develop more complex spectrum sensing systems that are not reliant on expert features. Architectures like Convolutional Neural Networks (CNN) and Recurrent Neural Networks (RNN) have shown great promise for applications like automated modulation classification, signal detection, and specific emitter ID. Research in these areas has primarily focused on "one size fits all" networks that assume a fixed signal length in both training and inference. However, since some signals are more complex than others, due to channel conditions, transmitter/receiver effects, etc., being able to dynamically utilize just enough of the received symbols to make a reliable decision allows for more efficient decision making in applications such as electronic warfare and dynamic spectrum sharing. Additionally, the operator may want to get to the quickest possible decision. Recurrent neural networks have been shown to outperform other architectures when processing temporally correlated data, such as from wireless communication signals. However, compared to other architectures, such as CNNs, RNNs can suffer from drastically longer training and evaluation times due to their inherent sample-by-sample data processing. While traditional usage of both of these architectures typically assumes a fixed observation interval during both training and testing, the sample-by-sample processing capabilities of recurrent neural networks opens the door for "decoupling" these intervals. This is invaluable in real-world applications due to the relaxation of the typical requirement of a fixed time duration of the signals of interest. This work illustrates the benefits and considerations needed when "decoupling" these observation intervals for spectrum sensing applications. In particular, this work shows that, intuitively, recurrent neural networks can be leveraged to process less data (i.e. shorter observation intervals) for simpler inputs (less complicated signal types or channel conditions). Less intuitively, this works shows that the "decoupling" is dependent on appropriate training to avoid bias and insure generalization.
44
Kellerman, Valpre Cecilia. "Modular approach to the development of a two-way radio receiver system". Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16362.
Testo completoAbstract (sommario):
Thesis (MScIng)--University of Stellenbosch, 2004.ENGLISH ABSTRACT: The preliminary development of a FM radio receiver module is discussed. An existing narrowband system operating between 48MHz and 50MHz will be replaced. Digital components were investigated, compared and used with analogue techniques to build a more flexible two-way radio receiver system. A direct digital synthesizer was considered as a replacement for the current synthesized phased lock loop local oscillator and much attention was given to the local oscillator and mixer design, characteristics and measurement procedures. A detailed study of receiver systems was undertaken to determine the specifications needed for every receiver component to achieve satisfactory receiver performance in the end. Receiver characteristics as well as receiver measurement procedures are defined. A software tool was developed to aid the design process, establishing computationally whether the receiver specifications are met prior to the final design. The complete design process, from fundamental specifications through to the developed final receiver module is discussed. A modular design approach was used to guarantee easy manufacturing, substitution and testing. This approach comprises the break-down of the receiver into well defined components that are each matched to 50O. The separate components of the system were designed, measured and characterized to make it possible to replace only a single component instead of the entire system when a part becomes redundant.
AFRIKAANSE OPSOMMING: Die grondslag vir die ontwikkeling van ‘n FM radio ontvanger module word in hierdie dokument gelê. ‘n Bestaande noubandstelsel wat tussen 48MHz and 50MHz ontvang word vervang deur hierdie nuwe stelsel wat aangewend sal kan word in die bestaande tweerigtingradio se omhulsel. Digitale komponente is ondersoek, vergelyk en gebruik saam met analoogtegnieke om ‘n meer buigsame radiostelsel te bewerkstellig. ‘n Direkte digitale sintitiseerder is oorweeg as ‘n vervanging vir die huidige fasesluitlus ossillator met heelwat klem op die oscillator-en mengerontwerp, komponent spesifikasies en metingsprosedures. ‘n Diepgaande studie van ontvangerstelsels is gedoen om te bepaal wat die tipiese spesifikasies vir elke ontvangerstadium is, sodat die finale ontvanger se spesifikasies behaal kan word. Ontvanger eienskappe en meetprosedures word volledig gedefinieer. ‘n Sagtewareprogram is ontwikkel om die ontvanger-ontwerpsproses te vergemaklik deur vooraf te kan vasstel watter ontvangerspesifikasies bereik sal kan word al dan nie. Die volledige ontwerpsproses, vanaf fundamentele spesifikasies tot by die finale ontvanger word omskryf. ‘n Modulere-ontwerp prosedure is gebruik ter versekering van die maklike vervaardiging, vervanging en toetsing van elke komponent. Die radio is tydens ontwerp opgebreek in boublokkies wat elkeen aangepas word na 50O. Elke aparte boublokkie van die ontvangerstelsel is afsonderlik ontwerp, gemeet en volledig gespesifiseer om dit moontlik te maak om slegs een komponent te vervang in plaas van die hele stelsel wanneer ‘n enkele komponent nie meer beskikbaar is nie.
45
Goyal, Abhilash. "Methodologies for low-cost testing and self-healing of rf systems". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44705.
Testo completoAbstract (sommario):
This thesis proposes a multifaceted production test and post-manufacture yield enhancement framework for RF systems. This framework uses low-cost test and post-manufacture calibration/tuning techniques. Since the test cost and the yield of the RF circuits/sub-system directly contribute to the manufacturing cost of RF systems, the proposed framework minimizes overall RF systems' manufacturing cost by taking two approaches. In the first approach, low-cost testing methodologies are proposed for RF amplifiers and integrated RF substrates with an embedded RF passive filter and interconnect. Techniques are developed to test RF circuits by the analysis of low-frequency signal of the order of few MHz and without using any external RF test-stimulus. Oscillation principles are used to enable testing of RF circuits without any external test-stimulus. In the second approach, to increase the yield of the RF circuits for parametric defects, RF circuits are tuned to compensate for a performance loss during production test using on-board or on-chip resources. This approach includes a diagnosis algorithm to identify faulty circuits within the system, and performs a compensation process that adjusts tunable components to enhance the performance of the RF circuits. In the proposed yield improvement methodologies, the external test stimulus is not required because the stimulus is generated by the RF circuit itself with the help of additional circuitry and faulty circuits are detected using low-cost test methods developed in this research. As a result, the proposed research enables low-cost testing and self-healing of RF systems.
46
Barjami, Saimir. "A New AC-Radio Frequency Heating Calorimetry Technique for Complex Fluids". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-042805-132440/.
Testo completoAbstract (sommario):
Dissertation (Ph.D.) -- Worcester Polytechnic Institute.Keywords: random-field interactions; radio frequency field heating; modulation calorimetry technique; heat capacity; aerosil; nematic; isotropic; phase transitions Includes bibliographical references.
47
Kim, Eung Jung. "Highly efficient supply modulator for mobile communication systems". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41058.
Testo completoAbstract (sommario):
Switching frequency modulation techniques, an inductor current sensing circuit for fast switching converter, and a dual converter are proposed, and the simulation results and experimental results are drawn. The experimental results for monotonic and pseudo-random modulation techniques show that the switching noise peak was effectively reduced as much as -19 dBc. The inductor current sensing circuit accurately tracks the output current of the switching converter that switches up to 30MHz. This current sensing circuit is used to drive the slow converter in the dual converter. The dual converter consists of a fast converter and a slow converter. The fast converter provides only the high frequency conponents in the output current, and the slow converter provides the majority portion of the output current with a higher efficiency. Therefore, the dual converter can have a fast transient response without sacrificing its efficiency. All chips are fabricated in a standard CMOS 0.18um process.
48
Laha, Soumyasanta. "Analysis & Design of Radio Frequency Wireless Communication Integrated Circuits with Nanoscale Double Gate MOSFETs". Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1418730974.
Testo completo
49
Wang, Ruonan. "Enhancement/depletion-mode HEMT technology for III-nitride mixed-signal and RF applications /". View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?ECED%202008%20WANG.
Testo completo
50
Fortin, Michel. "Contribution au développement d'un capteur optique de champ électrique /". Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2002. http://theses.uqac.ca.
Testo completo