Digital Speech Transmission

Speech processing and speech transmission technology are expanding fields of active research. New challenges arise from the 'anywhere, anytime' paradigm of mobile communications, the ubiquitous use of voice communication systems in noisy environments and the convergence of communication networks toward Internet based transmission protocols, such as Voice over IP. As a consequence, new speech coding, new enhancement and error concealment, and new quality assessment methods are emerging. Advances in Digital Speech Transmission provides an up-to-date overview of the field, including topics such as speech coding in heterogeneous communication networks, wideband coding, and the quality assessment of wideband speech. Provides an insight into the latest developments in speech processing and speech transmission, making it an essential reference to those working in these fields Offers a balanced overview of technology and applications Discusses topics such as speech coding in heterogeneous communications networks, wideband coding, and the quality assessment of the wideband speech Explains speech signal processing in hearing instruments and man-machine interfaces from applications point of view Covers speech coding for Voice over IP, blind source separation, digital hearing aids and speech processing for automatic speech recognition Advances in Digital Speech Transmission serves as an essential link between the basics and the type of technology and applications (prospective) engineers work on in industry labs and academia. The book will also be of interest to advanced students, researchers, and other professionals who need to brush up their knowledge in this field.

This introduction to digital data transmission, modulation, and error-correction coding, together with the underlying communication and information theory is an all-inclusive text suitable for all those connected with Mechanical Engineering or Computer Science. Equal emphasis is given to underlying mathematical theory and engineering practice. Not meant to be an encyclopedic treatise, the book offers strong, accessible pedagogy. This Second Edition presents enhanced explanations of key ideas as well as additional examples and problems. It also provides greatly expanded coverage of wireless communication, which has seen exponential growth since the release of the first edition. A pedagogocal approach aimed at the 5th year EE student A balance of theory with engineering and design Integration of important topics such as synchronization, radio channels, and wireless communication, which are left out of competing books, or lost in more lengthy formats.

Automatic speech recognition (ASR) is a very attractive means for human-machine interaction. The degree of maturity reached by speech recognition technologies during recent years allows the development of applications that use them. In particular, ASR shows an enormous potential in mobile environments, where devices such as mobile phones or PDAs are used, and for Internet Protocol (IP) applications. Speech Recognition Over Digital Channels is the first book of its kind to offer a complete system comprehension, addressing the topics of distributed and network-based speech recognition issues and standards, the concepts of speech processing and transmission, and system architectures and robustness. Describes the different client/server architectures for remote speech recognition systems, by means of which the client transmits speech parameters through a digital channel to a remote recognition server Focuses on robustness against both adverse acoustic environments (in the front-end) and bit errors/packet loss Discusses four ETSI standards for distributed speech recognition; the understanding of the standards and the technologies behind them Provides the necessary background for the comprehension of remote speech recognition technologies This book will appeal to a wide-ranging audience: engineers using speech recognition systems, researchers involved in ASR systems and those interested in processing and transmitting speech such as signal processing and communications communities. It will also be of interest to technical experts requiring an understanding of recognition over mobile and IP networks, and postgraduate students working on robust speech processing.

Provides a step-by-step description of the basics of precoding and signal shaping. * Illustrates theory with examples from wireline and wireless communications. * Discusses the role of precoding and signal shaping algorithms in communications standards.

In the last 30 years there have been dramatic changes in electrical technology–yet the length of the undergraduate curriculum has remained four years. Until some ten years ago, the analysis of transmission lines was a standard topic in the EE and CpE undergraduate curricula. Today most of the undergraduate curricula contain a rather brief study of the analysis of transmission lines in a one-semester junior-level course on electromagnetics. In some schools, this study of transmission lines is relegated to a senior technical elective or has disappeared from the curriculum altogether. This raises a serious problem in the preparation of EE and CpE undergraduates to be competent in the modern industrial world. For the reasons mentioned above, today's undergraduates lack the basic skills to design high-speed digital and high-frequency analog systems. It does little good to write sophisticated software if the hardware is unable to process the instructions. This problem will increase as the speeds and frequencies of these systems continue to increase seemingly without bound. This book is meant to repair that basic deficiency.

HVDC is a critical solution to several major problems encountered when trying to maintain systemic links and quality in large-scale renewable energy environments. HDVC can resolve a number of issues, including voltage stability of AC power networks, reducing fault current, and optimal management of electric power, ensuring the technology will play an increasingly important role in the electric power industry. To address the pressing need for an up-to-date and comprehensive treatment of the subject, Kim, Sood, Jang, Lim and Lee have collaborated to produce this key text and reference. Combining classroom-tested materials from North America and Asia, HVDC Transmission compactly summarizes the latest research results, and includes the insights of experts from power systems, power electronics, and simulation backgrounds. The authors walk readers through basic theory and practical applications, while also providing the broader historical context and future development of HVDC technology. Presents case studies covering basic and advanced HVDC deployments headed by world-renowned experts Demonstrates how to design, analyze and maintain HVDC systems in the field Provides updates on new HVDC technologies, such as active power filters, PWM, VSC, and 800 KV systems Rounds out readers' understanding with chapters dedicated to the key areas of simulation and main circuit design Introduces wind power system interconnection with HVDC Arms readers with an understanding of future HVDC trends Balancing theoretical instruction with practical application, HVDC Transmission delivers comprehensive working knowledge to power utility engineers, power transmission researchers, and advanced undergraduates and postgraduates in power engineering programs. The book is also a useful reference to for engineers and students focused on closely related areas such as renewable energy and power system planning.

A complete overview of distant automatic speech recognition The performance of conventional Automatic Speech Recognition (ASR) systems degrades dramatically as soon as the microphone is moved away from the mouth of the speaker. This is due to a broad variety of effects such as background noise, overlapping speech from other speakers, and reverberation. While traditional ASR systems underperform for speech captured with far-field sensors, there are a number of novel techniques within the recognition system as well as techniques developed in other areas of signal processing that can mitigate the deleterious effects of noise and reverberation, as well as separating speech from overlapping speakers. Distant Speech Recognitionpresents a contemporary and comprehensive description of both theoretic abstraction and practical issues inherent in the distant ASR problem. Key Features: Covers the entire topic of distant ASR and offers practical solutions to overcome the problems related to it Provides documentation and sample scripts to enable readers to construct state-of-the-art distant speech recognition systems Gives relevant background information in acoustics and filter techniques, Explains the extraction and enhancement of classification relevant speech features Describes maximum likelihood as well as discriminative parameter estimation, and maximum likelihood normalization techniques Discusses the use of multi-microphone configurations for speaker tracking and channel combination Presents several applications of the methods and technologies described in this book Accompanying website with open source software and tools to construct state-of-the-art distant speech recognition systems This reference will be an invaluable resource for researchers, developers, engineers and other professionals, as well as advanced students in speech technology, signal processing, acoustics, statistics and artificial intelligence fields.

Finally a comprehensive overview of speech quality in VoIP from the user’s perspective! Speech Quality of VoIP is an essential guide to assessing the speech quality of VoIP networks, whilst addressing the implications for the design of VoIP networks and systems. This book bridges the gap between the technical network-world and the psychoacoustic world of quality perception. Alexander Raake’s unique perspective combines awareness of the technical characteristics of VoIP networks and original research concerning the perception of speech transmitted across them. Starting from the network designer’s point of view, the different characteristics of the network are addressed, and then linked to features perceived by users. This book provides an overview of the available knowledge on the principal, relevant aspects of speech and speech quality perception, of speech quality assessment, and of transmission properties of telephone and VoIP networks, and of the related perceptual features and resulting speech quality. Discussing new research into the specific time-varying degradations VoIP brings along, but also the considerable potential of quality improvement to be achieved with wideband speech transmission, Alexander Raake demonstrates how network and service characteristics impact on the users perception of quality. Speech Quality of VoIP: Offers an insight into speech quality of VoIP from a user's perspective. Presents an overview of different modelling approaches and a parametric network-planning model for quality prediction in VoIP networks. Draws on innovative new research on the quality degradation characteristic of VoIP. Explains in detail how telephone speech quality can be greatly enhanced with VoIP’s wideband speech transmission capability. Assesses the vast collection of references into the technical and scientific literature related to VoIP quality. Illustrates concepts throughout with mathematical models, algorithms and simulations. Speech Quality of VoIP is the definitive guide for researchers, engineers and network planners working in the field of VoIP, Quality of Service, and speech communication processing in telecommunications. Advanced undergraduate and graduate students on telecommunication and networking courses will also find this text an invaluable resource.

The text sets out in simple and accessible terms the various methods of acoustic analysis of speech, placing them in their historical context, allowing a better understanding of the mathematical and technical solutions adopted today in phonetics and experimental phonology. Without mathematical complications, the operating bases of the many speech analysis software currently available are exposed so that everyone can understand the limits and avoid errors and misinterpretations in their implementation.

The development of power semiconductors with greater ratings and improved characteristics has meant that the power industry has become more willing to develop new converter configurations. These new configurations take advantage of the higher controllability and switching frequencies of the new devices. The next few years will decide which of the proposed technologies will dominate future power transmission systems. Flexible Power Transmission is a comprehensive guide to the high voltage direct current (HVDC) options available, helping the reader to make informed decisions for designing future power transmission systems. The book includes: a full description of the principles and components in existing converter technology, as well as alternative proposals for self-commutating conversion; A review of the state of power semiconductors suited to HVDC transmission and present proposals for multi-level HVDC transmission. a detailed overview of the flexible HVDC methods for improving controllability and increasing power transfer capability in electrical power systems. up-to-date information on thyrisistor-based HVDC technology. coverage of new pulse width modulation (PWM) transmission technology and multi-level voltage source conversion (VSC) and current source conversion (CSC). An excellent reference for professional power engineers, Flexible Power Transmission is also a useful guide for power system researchers as well as lecturers and students in power systems and power electronics disciplines.