Ultra Low Bit-Rate Speech Coding


Book Description

"Ultra Low Bit-Rate Speech Coding" focuses on the specialized topic of speech coding at very low bit-rates of 1 Kbits/sec and less, particularly at the lower ends of this range, down to 100 bps. The authors set forth the fundamental results and trends that form the basis for such ultra low bit-rates to be viable and provide a comprehensive overview of various techniques and systems in literature to date, with particular attention to their work in the paradigm of unit-selection based segment quantization. The book is for research students, academic faculty and researchers, and industry practitioners in the areas of speech processing and speech coding.




Digital Speech


Book Description

Digital Speech Coding for Low Bit Rate Communications Systems A. M. Kondoz University of Surrey UK Speech communication is still the dominant service in telecommunications networks. However, modern information requirements, such as multimedia, satellite and mobile communications, have created the need for a more robust and flexible alternative to the traditional analogue system. Digital speech transmission offers many advantages over its analogue counterpart, including consistent quality, versatility, security and successful integration into ISDN. This topical book provides an in-depth account of the latest developments in digital speech coders specifically designed for use in the evolving communications systems. Features include: * Fundamental material on sampling and quantisation. * Detailed coverage of speech signal analysis and modelling. * An examination of the key tools for speech coding. * Essential guidance on coding strategies and standards. * A review of a wide range of speech coding techniques, such as low delay speech coding and multi-band excitation speech coders. * Important information on error control in speech transmission. * A comprehensive assessment of system applications and real-time implementations, including unique coverage of the important code-excited linear prediction (CELP) method of speech coding. A complete examination of the theoretical design and practical applications of speech coders, this book will be invaluable for practising communications engineers, network designers and computer scientists. Advanced students in electrical, electronic and communications engineering, computer networking and digital signal processing will also find this text a helpful reference source.




Digital Speech, 2Nd Ed


Book Description

This edition provides the fundamental technical background required for low bit rate speech coding and developments in digital speech coding techniques that are applicable to evolving communication systems. Chapters on Pitch Estimation and Voice-Unvoiced Classification of Speech, Harmonic Speech Coding and Multimode Speech Coding, are featured. It also offers expanded coverage of speech enhancement techniques such as echo cancellation and noise suppression. · Introduction · Coding Strategies and Standards · Sampling and Quantization · Speech Signal Analysis and Modelling · Efficient LPC Quantization Methods · Pitch Estimation and Voiced-Unvoiced Classification of Speech · Analysis by Synthesis LPC Coding · Harmonic Speech Coding · Multimode Speech Coding · Voice Activity Detection · Speech Enhancement




Speech and Audio Coding for Wireless and Network Applications


Book Description

Speech and Audio Coding for Wireless and Network Applications contains 34 chapters, loosely grouped into six topical areas. The chapters in this volume reflect the progress and present the state of the art in low-bit-rate speech coding, primarily at bit rates from 2.4 kbit/s to 16 kbit/s. Together they represent important contributions from leading researchers in the speech coding community. Speech and Audio Coding for Wireless and Network Applications contains contributions describing technologies that are under consideration as standards for such applications as digital cellular communications (the half-rate American and European coding standards). A brief Introduction is followed by a section dedicated to low-delay speech coding, a research direction which emerged as a result of the CCITT requirement for a universal low-delay 16 kbit/s speech coding technology and now continues with the objective of achieving toll quality with moderate delay at a rate of 8 kbit/s. A section on the important topic of speech quality evaluation is then presented. This is followed by a section on speech coding for wireless transmission, and a section on audio coding which covers not only 7 kHz bandwidth speech, but also wideband coding applicable to high fidelity music. The book concludes with a section on speech coding for noisy transmission channels, followed by a section addressing future research directions. Speech and Audio Coding for Wireless and Network Applications presents a cross-section of the key contributions in speech and audio coding which have emerged recently. For this reason, the book is a valuable reference for all researchers and graduate students in the speech coding community.




Communication Theory and Signal Processing for Transform Coding


Book Description

This book is tailored to fulfil the requirements in the area of the signal processing in communication systems. The book contains numerous examples, solved problems and exercises to explain the methodology of Fourier Series, Fourier Analysis, Fourier Transform and properties, Fast Fourier Transform FFT, Discrete Fourier Transform DFT and properties, Discrete Cosine Transform DCT, Discrete Wavelet Transform DWT and Contourlet Transform CT. The book is characterized by three directions, the communication theory and signal processing point of view, the mathematical point of view and utility computer programs. The contents of this book include chapters in communication system and signals, Fourier Series and Power Spectra, Fourier Transform and Energy Spectra, Fourier Transform and Power Spectra, Correlation Function and Spectral Density, Signal Transmission and Systems, Hilbert Transform, Narrow Band-Pass Signals and Systems and Numerical Computation of Transform Coding. This book is intended for undergraduate students in institutes, colleges, universities and academies who want to specialize in the field of communication systems and signal processing. The book will also be very useful to engineers of graduate and post graduate studies as well as researchers in research centers since it contains a great number of mathematical operations that are considered important in research results.




Advances in Speech Coding


Book Description

Speech coding has been an ongoing area of research for several decades, yet the level of activity and interest in this area has expanded dramatically in the last several years. Important advances in algorithmic techniques for speech coding have recently emerged and excellent progress has been achieved in producing high quality speech at bit rates as low as 4.8 kb/s. Although the complexity of the newer more sophisticated algorithms greatly exceeds that of older methods (such as ADPCM), today's powerful programmable signal processor chips allow rapid technology transfer from research to product development and permit many new cost-effective applications of speech coding. In particular, low bit rate voice technology is converging with the needs of the rapidly evolving digital telecom munication networks. The IEEE Workshop on Speech Coding for Telecommunications was held in Vancouver, British Columbia, Canada, from September 5 to 8, 1989. The objective of the workshop was to provide a forum for discussion of recent developments and future directions in speech coding. The workshop attracted over 130 researchers from several countries and its technical program included 51 papers.




Cryptography and Coding


Book Description

This monograph provides a formal and systematic exposition of the main results on the existence and optimality of equilibria in economies with increasing returns to scale. For that, a general equilibrium model is carefully constructed first by means of a precise formalization of consumers and firms, and the proof of an abstract existence result. The analysis shifts then to the study of specific normative and positive models which are particularizations the general one, and to the study of the efficiency of equilibrium allocations. The book provides an unified approach of the topic, it maintains a relatively low mathematical complexity and offers a highly self-contained exposition.







The Communications Handbook


Book Description

For more than six years, The Communications Handbook stood as the definitive, one-stop reference for the entire field. With new chapters and extensive revisions that reflect recent technological advances, the second edition is now poised to take its place on the desks of engineers, researchers, and students around the world. From fundamental theory to state-of-the-art applications, The Communications Handbook covers more areas of specialty with greater depth that any other handbook available. Telephony Communication networks Optical communications Satellite communications Wireless communications Source compression Data recording Expertly written, skillfully presented, and masterfully compiled, The Communications Handbook provides a perfect balance of essential information, background material, technical details, and international telecommunications standards. Whether you design, implement, buy, or sell communications systems, components, or services, you'll find this to be the one resource you can turn to for fast, reliable, answers.