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Zusatztext "...focuses on voice compression issues in wireless communications." (SciTech Book News! Vol. 25! No. 4! December 2001) Informationen zum Autor LAJOS HANZO has coauthored five books on mobile radio communications and published more than 300 research papers on a variety of topics in wireless multimedia communications. He holds a chair in telecommunications at the Department of Electronics and Computer Science, University of Southampton, UK, and he is an IEEE Distinguished Lecturer. F. CLARE A. SOMERVILLE is with the Global Wireless Systems Research Department, Bell Laboratories, Swindon, UK. His current research involves real-time techniques for transmission of voice over GPRS and the resultant speech quality attained. JASON P. WOODARD is with UbiNetics Ltd., where he is responsible for the development and implementation of various algorithms for third-generation mobile communications products. Klappentext Up-to-date, expert coverage of topics in wireless voice communications Voice communication is the most important facet of mobile radio service. Even when the predicted surge of wireless data and Internet services becomes a reality, voice will remain the most natural means of human communication. Voice Compression and Communications details issues in wireless voice communications and treats compression, channel coding, and wireless transmission as a joint subject. Part I covers background material, whereas Part II provides detailed information on both proprietary and standardized analysis-by-synthesis codecs, including the speech codecs of virtually all existing wireline-based and wireless systems. Parts III and IV discuss mainly research-based wideband, audio, as well as very low-rate schemes likely to find their way into future standards. Voice Compression and Communications describes fundamental concepts in a non-mathematical way early in the book for those with only a background knowledge of signal processing and communications. More advanced readers will find detailed discussions of theoretical principles, future concepts, and solutions to various specific wireless voice communications problems. Zusammenfassung Voice communication is the most important facet of mobile radio service. Even when the predicted surge of wireless data and Internet services becomes a reality, voice will remain the most natural means of human communication. This book provides coverage of topics in wireless voice communications. Inhaltsverzeichnis Preface xxiii Acknowledgments xxix Part I Speech Signals and Waveform Coding 1 Chapter 1 Speech Signals and Introduction to Speech Coding 3 1.1 Motivation of Speech Compression 3 1.2 Basic Characterization of Speech Signals 4 1.3 Classification of Speech Codecs 7 1.4 Waveform Coding 11 1.5 Chapter Summary 26 Chapter 2 Predictive Coding 27 2.1 Forward Predictive Coding 27 2.2 DPCM Codec Schematic 28 2.3 Predictor Design 29 2.4 Adaptive One-Word-Memory Quantization 36 2.5 DPCM Performance 37 2.6 Backward-Adaptive Prediction 39 2.7 The 32kbps G.721 ADPCM Codec 43 2.8 Subjective and Objective Speech Quality 49 2.9 Variable-Rate G.726 and Embedded G.727 ADPCM 50 2.10 Rate-Distortion in Predictive Coding 58 2.11 Chapter Summary 62 Part II Analysis by Synthesis Coding 63 Chapter 3 Analysis-by-Synthesis Principles 65 3.1 Motivation 65 3.2 Analysis-by-Synthesis Codec Structure 66 3.3 The Short-Term Synthesis Filter 67 3.4 Long-Term Prediction 70 3.5 Excitation Models 78 3.6 Adaptive Short-Term and Long-Term Post-Filtering 81 3.7 Lattice-Based Linear Prediction 83 3.8 Chapter Summary 89 Chapter 4 Speech Spectral Quantization 90 4.1 Log-Area ...
