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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Linearity and monotonicity of a 10-bit, 125 MHz, segmented current steering digital to analog converter

Bittle, Charles C. 05 1900 (has links)
The purpose of this research is to determine the linearity and monotonicity of the THS5651IDW digital to analog converter (DAC), a prototype of the future Texas Instruments TLV5651, 10-bit, 125 MHz communication DAC. Testing was conducted at the Texas Instruments facility on Forest Lane, Dallas, Texas. Texas Instruments provided test equipment, software and laboratory space to obtain test data. Analysis of the data found the DAC to be monotonic since the magnitude of the differential nonlinearity (DNL) was less than ± 1 least significant bit (LSB) and the integral nonlinearity (INL) was less than ± 0.5 LSB. The study also showed that the DAC has primarily negative DNL although the DNL is well within the desired specification.
152

Optimal soft-decoding combined trellis-coded quantization/modulation.

January 2000 (has links)
Chei Kwok-hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 66-73). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Typical Digital Communication Systems --- p.2 / Chapter 1.1.1 --- Source coding --- p.3 / Chapter 1.1.2 --- Channel coding --- p.5 / Chapter 1.2 --- Joint Source-Channel Coding System --- p.5 / Chapter 1.3 --- Thesis Organization --- p.7 / Chapter Chapter 2 --- Trellis Coding --- p.9 / Chapter 2.1 --- Convolutional Codes --- p.9 / Chapter 2.2 --- Trellis-Coded Modulation --- p.12 / Chapter 2.2.1 --- Set Partitioning --- p.13 / Chapter 2.3 --- Trellis-Coded Quantization --- p.14 / Chapter 2.4 --- Joint TCQ/TCM System --- p.17 / Chapter 2.4.1 --- The Combined Receiver --- p.17 / Chapter 2.4.2 --- Viterbi Decoding --- p.19 / Chapter 2.4.3 --- Sequence MAP Decoding --- p.20 / Chapter 2.4.4 --- Sliding Window Decoding --- p.21 / Chapter 2.4.5 --- Block-Based Decoding --- p.23 / Chapter Chapter 3 --- Soft Decoding Joint TCQ/TCM over AWGN Channel --- p.25 / Chapter 3.1 --- System Model --- p.26 / Chapter 3.2 --- TCQ with Optimal Soft-Decoder --- p.27 / Chapter 3.3 --- Gaussian Memoryless Source --- p.30 / Chapter 3.3.1 --- Theorem Limit --- p.31 / Chapter 3.3.2 --- Performance on PAM Constellations --- p.32 / Chapter 3.3.3 --- Performance on PSK Constellations --- p.36 / Chapter 3.4 --- Uniform Memoryless Source --- p.38 / Chapter 3.4.1 --- Theorem Limit --- p.38 / Chapter 3.4.2 --- Performance on PAM Constellations --- p.39 / Chapter 3.4.3 --- Performance on PSK Constellations --- p.40 / Chapter Chapter 4 --- Soft Decoding Joint TCQ/TCM System over Rayleigh Fading Channel --- p.42 / Chapter 4.1 --- Wireless Channel --- p.43 / Chapter 4.2 --- Rayleigh Fading Channel --- p.44 / Chapter 4.3 --- Idea Interleaving --- p.45 / Chapter 4.4 --- Receiver Structure --- p.46 / Chapter 4.5 --- Numerical Results --- p.47 / Chapter 4.5.1 --- Performance on 4-PAM Constellations --- p.48 / Chapter 4.5.2 --- Performance on 8-PAM Constellations --- p.50 / Chapter 4.5.3 --- Performance on 16-PAM Constellations --- p.52 / Chapter Chapter 5 --- Joint TCVQ/TCM System --- p.54 / Chapter 5.1 --- Trellis-Coded Vector Quantization --- p.55 / Chapter 5.1.1 --- Set Partitioning in TCVQ --- p.56 / Chapter 5.2 --- Joint TCVQ/TCM --- p.59 / Chapter 5.2.1 --- Set Partitioning and Index Assignments --- p.60 / Chapter 5.2.2 --- Gaussian-Markov Sources --- p.61 / Chapter 5.3 --- Simulation Results and Discussion --- p.62 / Chapter Chapter 6 --- Conclusion and Future Work --- p.64 / Chapter 6.1 --- Conclusion --- p.64 / Chapter 6.2 --- Future Works --- p.65 / Bibliography --- p.66 / Appendix-Publications --- p.73
153

Adaptive feedforward linearized microwave amplifiers for digital communication systems.

January 2001 (has links)
Lin Pui-Yu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 103-105). / Abstracts in English and Chinese. / Acknowledgement / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Nonlinear Phenomenon of Power Amplifier --- p.5 / Chapter 2.1. --- AM-AM and AM-PM Distortion --- p.5 / Chapter 2.2. --- Intermodulation Distortion --- p.7 / Chapter Chapter 3 --- Linearization Techniques --- p.10 / Chapter 3.1. --- Power Backoff --- p.11 / Chapter 3.2. --- Feedback --- p.12 / Chapter 3.3. --- Predistortion --- p.12 / Chapter 3.4. --- Feedforward --- p.14 / Chapter 3.5. --- Other Linearization Techniques --- p.15 / Chapter Chapter 4 --- Analysis of Feedforward Power Amplifier --- p.17 / Chapter 4.1. --- Feedforward Efficiency --- p.18 / Chapter 4.2. --- Design Criteria of the Auxiliary Amplifier --- p.20 / Chapter 4.3. --- Sensitivity Analysis --- p.21 / Chapter 4.3.1. --- Phase and Amplitude Mismatch --- p.22 / Chapter 4.3.2. --- Delay Mismatch --- p.23 / Chapter 4.3.3. --- Combined Effect --- p.25 / Chapter 4.3.4. --- Practical Consideration --- p.27 / Chapter 4.4. --- Other Design Criteria --- p.28 / Chapter Chapter 5 --- Adaptive Control Networks for FFPA --- p.29 / Chapter 5.1. --- Basic Principles of the Adaptive Control Network --- p.30 / Chapter 5.1.1. --- Lookup Table --- p.30 / Chapter 5.1.2. --- Power Minimization Vs. Correlation --- p.31 / Chapter 5.2. --- Analog Vs Digital Implementation of the Adaptive Control Network --- p.34 / Chapter 5.3. --- Techniques for Improving the Convergence Behaviour at the Distortion Cancellation Loop --- p.35 / Chapter 5.4. --- Important Notes on the Control Networks --- p.38 / Chapter Chapter 6 --- Novel Analysis of Adaptive FFPA --- p.40 / Chapter 6.1. --- Gradient algorithm --- p.40 / Chapter 6.2. --- Dual Loop Adaptive FFPA --- p.41 / Chapter 6.2.1. --- System Modeling --- p.42 / Chapter 6.2.2. --- Adaptation Behavior of the Distortion Extraction Loop --- p.44 / Chapter 6.2.3. --- Adaptation Behavior of the Distortion Cancellation Loop --- p.48 / Chapter 6.2.4. --- Accuracy Requirement of the Control Signals --- p.50 / Chapter 6.2.5. --- Effect of Delay Mismatch on the Convergence Accuracy --- p.51 / Chapter 6.2.6. --- Convergence Behaviors for Two Tone Input Signal --- p.52 / Chapter 6.2.6.1. --- Distortion Extraction Loop --- p.53 / Chapter 6.2.6.2. --- Distortion Cancellation Loop --- p.55 / Chapter 6.2.6.3. --- Simulation Results --- p.57 / Chapter 6.2.7. --- Convergence Behaviors for Digital Modulated Test signal --- p.60 / Chapter 6.2.7.1. --- Distortion Extraction Loop --- p.61 / Chapter 6.2.7.2. --- Distortion Cancellation Loop --- p.66 / Chapter 6.2.7.3. --- Simulation Results --- p.68 / Chapter 6.2.8. --- Comparison for the Adaptation Performance with Two Tone and Digital Modulated Test Signal --- p.70 / Chapter 6.3. --- Triple Loop Adaptive FFPA --- p.71 / Chapter 6.3.1. --- Adaptation Performance of the Additional Loop --- p.73 / Chapter 6.3.2. --- Adaptation Performance of the Distortion Cancellation Loop --- p.75 / Chapter 6.3.3. --- Improvement in Bias Error at the Distortion Cancellation Loop --- p.76 / Chapter 6.3.4. --- Effect of Delay Mismatch --- p.77 / Chapter 6.3.5. --- Simulation Results --- p.79 / Chapter Chapter 7 --- Implementation and Measured Performance of Triple Loop Adaptive FFPA --- p.85 / Chapter 7.1. --- Hardware Design --- p.85 / Chapter 7.1.1. --- Vector Modulator --- p.87 / Chapter 7.1.2 --- Complex Correlator --- p.88 / Chapter 7.2. --- Experimental Setup and Measured Results --- p.90 / Chapter Chapter 8 --- Conclusion --- p.95 / Appendix I Matlab Program for Simulation of Dual Loop Adaptive FFPA --- p.97 / Appendix II Matlab Program for Simulation of Triple Loop Adaptive FFPA --- p.100 / Reference --- p.103 / Author's Publication --- p.106
154

Techniques for unequal error protection.

January 2001 (has links)
Ho Man-Shing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 65-66). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / List of Abbreviation --- p.iii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Digital Communication System --- p.3 / Chapter 1.2 --- Thesis Organization --- p.4 / Chapter 2. --- Error-Correcting Codes --- p.6 / Chapter 2.1 --- Convolutional Codes --- p.7 / Chapter 2.1.1 --- Generator Polynomials --- p.8 / Chapter 2.1.2 --- Generator Matrix --- p.9 / Chapter 2.1.3 --- Circuit Diagram --- p.10 / Chapter 2.1.4 --- State-transition Diagram --- p.11 / Chapter 2.1.4 --- Trellis Diagram --- p.12 / Chapter 2.1.5 --- Distance property --- p.13 / Chapter 2.2 --- Rate-Compatible Punctured Convolutional Codes --- p.14 / Chapter 2.3 --- Trellis-Coded Modulation --- p.17 / Chapter 2.3.1 --- General Model of TCM --- p.18 / Chapter 2.3.2 --- Trellis Representation --- p.20 / Chapter 2.3.3 --- Set Partitioning --- p.21 / Chapter 2.3.4 --- Code Modulation --- p.23 / Chapter 2.4 --- Decoding Algorithm --- p.25 / Chapter 2.4.1 --- Viterbi Algorithm --- p.27 / Chapter 2.4.2 --- List Viterbi Algorithm --- p.30 / Chapter 3. --- Unequal-Error-Protection for Embedded Image Coder --- p.33 / Chapter 3.1 --- SPIHT Coder --- p.35 / Chapter 3.1.1 --- Progressive Image Transmission --- p.36 / Chapter 3.1.2 --- Set Partitioning Sorting Algorithm --- p.37 / Chapter 3.1.3 --- Spatial Orientation Trees --- p.38 / Chapter 3.2 --- System Description --- p.39 / Chapter 3.3 --- Code Allocation --- p.41 / Chapter 3.4 --- System Complexity --- p.42 / Chapter 3.5 --- Simulation Result --- p.43 / Chapter 4. --- Unequal-Error-Protection Provided by Trellis-Coded Modulation --- p.51 / Chapter 4.1 --- System Description --- p.52 / Chapter 4.2 --- Unequal Constellation --- p.53 / Chapter 4.3 --- Free Distance --- p.55 / Chapter 4.4 --- Simulation Results --- p.59 / Chapter 5. --- Conclusion --- p.63 / Bibliography --- p.65
155

As teorias da comunicação aplicadas à narrativa transmídia

Miranda, Gabriela Dischinger 21 August 2017 (has links)
Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2017-08-30T12:55:55Z No. of bitstreams: 1 Gabriela Dischinger Miranda.pdf: 9361011 bytes, checksum: 6de1bfd60b91a107b8b069cc79027a3c (MD5) / Made available in DSpace on 2017-08-30T12:55:55Z (GMT). No. of bitstreams: 1 Gabriela Dischinger Miranda.pdf: 9361011 bytes, checksum: 6de1bfd60b91a107b8b069cc79027a3c (MD5) Previous issue date: 2017-08-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / From a brief overview of the main communication theories we can see that many that are still used today were thought between the decades of 1930 and 29160, based on mass communication; media that assumes asymmetric communication and one to many. Communication on digital media, on the other hand, is two way, in which the individual not only has the possibility to send their own messages, bus also respond to those they receive. Therefore, new digital media changed radically the communication environment, making it important to review the main communication theories seeking to identify those that can still explain multimedia and transmedia communication. In this dissertation, we mapped these main communication theories and detailed how digital and transmedia communication works. With four case studies we illustrated how communication happens today and looked for those communications theories that still fits in this scenario / A partir de um breve panorama das principais teorias da comunicação percebemos que a maioria das teorias que perduram até hoje foram pensadas entre 1930 e 1960 baseadas nos meios de comunicação de massa; meios esses que preveem uma comunicação assimétrica e de um para muitos. A comunicação nos meios digitais, por outro lado, é uma via de mão dupla, por meio da qual o indivíduo não apenas passou a ter a possibilidade de transmitir suas próprias mensagens, mas também responder àquelas que recebe. Dessa forma, as novas mídias digitais trouxeram uma grande mudança no ambiente comunicacional, o que torna importante a revisão das principais teorias da comunicação com o objetivo de identificar aquelas que ainda conseguem explicar a comunicação multimeios e transmidiática. Nessa dissertação mapeamos as principais teorias da comunicação e detalhamos a comunicação digital e transmidiática. Através quatro de estudos de caso ilustramos a comunicação hoje e buscamos as principais teorias da comunicação que ainda se encaixam nesse cenário
156

Méthodes décentralisées d'allocation des ressources dans le canal d'interférence acoustique sous-marin / Decentralized methods for resource allocation in the underwater acoustic interference channel

Pottier, Antony 15 November 2018 (has links)
L’onde acoustique est utilisée par de nombreux systèmes et organismes marins pour communiquer, naviguer ou inférer de l’information sur l’environnement. Le développement des activités humaines liées au monde de la mer induit une augmentation du nombre de sources acoustiques en activité simultanée dans l’océan. L’environnement acoustique sous-marin (ASM) est donc partagé par de nombreuses sources hétérogènes (sonars, modems, mammifères marins, ...) entrant involontairement en compétition pour l’utilisation d’une ressource offerte par le canal de transmission. L’objectif de ce travail de thèse est de proposer des solutions permettant aux systèmes de communications ASM d’adapter leurs paramètres de transmission de manière intelligente, autonome et décentralisée selon l’environnement acoustique dans lequel ils évoluent. A plusieurs égards, les problématiques de ce sujet de thèse sont proches de celles ayant motivé le développement des recherches sur la radio cognitive. Cependant, les spécificités du milieu acoustique, les sources d’interférencesde diverses natures, et l’absence de standards de communications posent de nouvelles difficultés. / Underwater acoustic waves are used by many systems and biologic organisms to communicate, navigate or infer information about the environment. Future developments of human maritime activities imply an increase of the number of active acoustic sources in the oceans. The underwater environment is therefore shared by many heterogeneous sources (sonars, modems, marine mammals, ...) competing involuntarily for using the physical resources offered by the communication channel.The goal of this thesis is to provide solutions allowing autonomous and decentralized adaptation of the transmission strategies of underwater acoustic communication systems, according to the environment. To some extent, this work deals with topics that are closely related to what has motivated the first researches on cognitive radio systems. However, the specific properties of the underwater environment, the heterogeneity of interfering acoustic sources, and the absence of communication standards rise new difficulties.
157

Joint coding and modulation designs for bandlimited satellite channels

Hui, Joseph Y. N January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Joseph Y. N. Hui. / M.S.
158

Critical analyses of some public-key cryptosystems for high-speed satellite transmission applications

Ma, Moses Hsingwen January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: leaves 83-86. / by Moses Hsingwen Ma. / M.S.
159

Jitter reduction techniques for digital audio.

January 1997 (has links)
by Tsang Yick Man, Steven. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 94-99). / ABSTRACT --- p.i / ACKNOWLEDGMENT --- p.ii / LIST OF GLOSSARY --- p.iii / Chapter 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- What is the jitter ? --- p.3 / Chapter 2 --- WHY DOES JITTER OCCUR IN DIGITAL AUDIO ? --- p.4 / Chapter 2.1 --- Poorly-designed Phase Locked Loop ( PLL ) --- p.4 / Chapter 2.1.1 --- Digital data problem --- p.7 / Chapter 2.2 --- Sampling jitter or clock jitter ( Δti) --- p.9 / Chapter 2.3 --- Waveform distortion --- p.12 / Chapter 2.4 --- Logic induced jitter --- p.17 / Chapter 2.4.1 --- Digital noise mechanisms --- p.20 / Chapter 2.4.2 --- Different types of D-type flop-flip chips are linked below for ease of comparison --- p.21 / Chapter 2.4.3 --- Ground bounce --- p.22 / Chapter 2.5 --- Power supply high frequency noise --- p.23 / Chapter 2.6 --- Interface Jitter --- p.25 / Chapter 2.7 --- Cross-talk --- p.28 / Chapter 2.8 --- Inter-Symbol-Interference (ISI) --- p.28 / Chapter 2.9 --- Baseline wander --- p.29 / Chapter 2.10 --- Noise jitter --- p.30 / Chapter 2.11 --- FIFO jitter reduction chips --- p.31 / Chapter 3 --- JITTER REDUCTION TECHNIQUES --- p.33 / Chapter 3.1 --- Why using two-stage phase-locked loop (PLL ) ? / Chapter 3.1.1 --- The PLL circuit components --- p.35 / Chapter 3.1.2 --- The PLL timing specifications --- p.36 / Chapter 3.2 --- Analog phase-locked loop (APLL ) circuit usedin second stage --- p.38 / Chapter 3.3 --- All digital phase-locked loop (ADPLL ) circuit used in second stage --- p.40 / Chapter 3.4 --- ADPLL design --- p.42 / Chapter 3.4.1 --- "Different of K counter value of ADPLL are listed for comparison with M=512, N=256, Kd=2" --- p.46 / Chapter 3.4.2 --- Computer simulated results and experimental results of the ADPLL --- p.47 / Chapter 3.4.3 --- PLL design notes --- p.58 / Chapter 3.5 --- Different of the all digital Phase-Locked Loop (ADPLL ) and the analogue Phase-Locked Loop (APLL ) are listed for comparison --- p.65 / Chapter 3.6 --- Discrete transistor oscillator --- p.68 / Chapter 3.7 --- Discrete transistor oscillator circuit operation --- p.69 / Chapter 3.8 --- The advantage and disadvantage of using external discrete oscillator --- p.71 / Chapter 3.9 --- Background of using high-precision oscillators --- p.72 / Chapter 3.9.1 --- The temperature compensated crystal circuit operation --- p.73 / Chapter 3.9.2 --- The temperature compensated circuit design notes --- p.75 / Chapter 3.10 --- The discrete voltage reference circuit operation --- p.76 / Chapter 3.10.1 --- Comparing the different types of Op-amps that can be used as a voltage comparator --- p.79 / Chapter 3.10.2 --- Precaution of separate CMOS chips Vdd and Vcc --- p.80 / Chapter 3.11 --- Board level jitter reduction method --- p.81 / Chapter 3.12 --- Digital audio interface chips --- p.82 / Chapter 3.12.1 --- Different brand of the digital interface receiver (DIR) chips and clock modular are listed for comparison --- p.84 / Chapter 4. --- APPLICATION CIRCUIT BLOCK DIAGRAMS OF JITTER REDUCTION AND CLOCK RECOVERY --- p.85 / Chapter 5 --- CONCLUSIONS --- p.90 / Chapter 5.1 --- Summary of the research --- p.90 / Chapter 5.2 --- Suggestions for further development --- p.92 / Chapter 5.3 --- Instrument listing that used in this thesis --- p.93 / Chapter 6 --- REFERENCES --- p.94 / Chapter 7 --- APPENDICES --- p.100 / Chapter 7.1.1 --- Phase instability in frequency dividers / Chapter 7.1.2 --- The effect of clock tree on Tskew on ASIC chip / Chapter 7.1.3 --- Digital audio transmission----Why jitter is important? / Chapter 7.1.4 --- Overview of digital audio interface data structures / Chapter 7.1.5 --- Typical frequency Vs temperature variations curve of Quartz crystals / Chapter 7.2 --- IC specification used in these research project
160

Intercalamento temporal por transformada de Fourier: um novo método robusto para transmissão de sinais de TV Digital. / Fourier transform based time interleaving.

Guido Stolfi 04 June 2008 (has links)
Este trabalho apresenta um novo algoritmo, denominado Intercalamento Temporal por Transformada de Fourier (FTI), desenvolvido para complementar sistemas de modulação digital. Com este processo, a informação é distribuida de forma difusa ao longo de um conjunto de símbolos, tanto no domínio do tempo como no da frequência. Constitui-se em um processo computacionalmente eficiente, especialmente adequado para operar em conjunto com a modulação OFDM, e que apresenta consideráveis ganhos de desempenho em algumas situações de degradação; por exemplo, é mais tolerante a ruídos impulsivos de longa duração do que a modulação OFDM convencional. Apresenta-se também um outro mecanismo, denominado de Realimentação de Erro, que melhora o desempenho do sistema em praticamente todas as situaçoes analisadas. Embora implique em aumento da carga computacional, este processo consiste de uma operação determinística, que dispensa etapas de iteração ou recursos computacionais distintos dos já disponíveis. Neste trabalho foi avaliada a utilização destas técnicas em um sistema OFDM com características similares ao sistema ISDB-T, adequado para radiodifusão de TV Digital . / This work introduces a new transform-based time interleaving algorithm: FTI-OFDM (Fourier Transform Interleaved OFDM), in which binary information is spread over several symbols, both in time and frequency domains. This process, designed to be included in digital modulation systems, is computationally efficient when used in conjunction with OFDM modulation. Simulations are used to show its superiority over the usual binary time interleaving used in ordinary OFDM under several impairment scenarios, that include long impulsive noise and deep fading. Also introduced in this work is the additional method of decision error feedback (ERF), that enhances the performance of FTI-OFDM in almost all situations. Furthermore, ERF is deterministic and non-iterative and employs the same computational resources found in OFDM systems. The performance of an FTI-OFDM system, similar to ISDB-T standard, is evaluated under several impairments, such as are found in Digital TV broadcasting environment.

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