After alm ost three scores of years of basic and applied research, the field of speech processing is, at present, undergoing a rapid growth in terms of both performance and applications and this is fueHed by the advan...
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ISBN:
(数字)9781475721485
ISBN:
(纸本)9780792392200;9781441951281
After alm ost three scores of years of basic and applied research, the field of speech processing is, at present, undergoing a rapid growth in terms of both performance and applications and this is fueHed by the advances being made in the areas of microelectronics, computation and algorithm *** processing relates to three aspects of voice communications: -Speech Coding and transmission which is mainly concerned with man-to man voice communication. -Speech Synthesis which deals with machine-to-man communication. -Speech Recognition which is related to man-to-machine communication. Widespread application and use of low-bit rate voice codec.>, synthesizers and recognizers which are all speech processing products requires ideaHy internationally accepted quality assessment and evaluation methods as weH as speech processing standards so that they may be interconnected and used independently of their designers and manufacturers without costly interfaces. This book presents, in a tutorial manner, both fundamental and applied aspects of the above topics which have been prepared by weH-known specialists in their respective areas. The book is based on lectures which were sponsored by AGARD/NATO and delivered by the authors, in several NATO countries, to audiences consisting mainly of academic and industrial R&D engineers and physicists as weH as civil and military C3I systems planners and designers.
Wireless Local Area Networks (WLANs) experience a growing popularity recently. Where WLANs were primarily used for niche applications in the past, they are now deployed as wireless extensions to computer networks. The...
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ISBN:
(数字)9780306476853
ISBN:
(纸本)9781402071164;9781475784596
Wireless Local Area Networks (WLANs) experience a growing popularity recently. Where WLANs were primarily used for niche applications in the past, they are now deployed as wireless extensions to computer networks. The increase of the datarates from 2 Mbps up to 11 Mbps for roughly a constant price has played a major role in this breakthrough. As a consequence, an even greater success can be envisioned for the more recent OFDM-based WLAN standards in the 5 GHz band, which offer up to 54 Mbps. At IMEC we have realised this potential already several years ago and have established a successful research programme on OF- based WLAN. In 1995, we started our research on wireless OFDM in the frame of a - operation project with SAIT, a Belgian telecom company. The goal of the project was to establish a robust network for industrial environments. This resulted in a first OFDM chip, supporting QPSK, for wireless networking at the end of the project (1999). 1999 was also the start of an intense co-operation with National Semiconductor Inc., which resulted in a second generation ASIC in 2000. This OFDM processor supports up to QAM-64 and has a more optimal channel estimation algorithm.
A major advantage of a direct digital synthesizer (DDS) is that its output frequency, phase and amplitude can be precisely and rapidly manipulated under digital processor control. Other inherent DDS attributes incl...
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ISBN:
(数字)9781475733952
ISBN:
(纸本)9780792373667;9781441948953
A major advantage of a direct digital synthesizer (DDS) is that its output frequency, phase and amplitude can be precisely and rapidly manipulated under digital processor control. Other inherent DDS attributes include the ability to tune with extremely fine frequency and phase resolution, and to rapidly `hop' between frequencies. These combined characteristics have made the technology popular in military radar and communications systems. In fact, DDS technology was previously applied almost exclusively to high-end and military applications: it was costly, power-hungry, difficult to implement, and required a discrete high speed D/A converter. Due to improved integrated circuit (IC) technologies, they now present a viable alternative to analog-based phase-locked loop (PLL) technology for generating agile analog output frequency in consumer synthesizer applications.;It is easy to include different modulation capabilities in the DDS by using digital signal processing (DSP) methods, because the signal is in digital form. By programming the DDS, adaptive channel bandwidths, modulation formats, frequency hopping and data rates are easily achieved. The flexibility of the DDS makes it ideal for signal generator for software radio. The digital circuits used to implement signal-processing functions do not suffer the effects of thermal drift, aging and component variations associated with their analog counterparts. The implementation of digital functional blocks makes it possible to achieve a high degree of system integration. Recent advances in IC fabrication technology, particularly CMOS, coupled with advanced DSP algorithms and architectures are providing possible single-chip DDS solutions to complex communication and signal processing subsystems as modulators, demodulators, local oscillators, programmable clock generators, and chirp generators. The DDS addresses a variety of applications, including cable modems, measurement equipments, arbitrary
oW should coded communication be approached? Is it about prob H ability theorems and bounds, or about algorithms and structures? The traditional course in information theory and coding teaches these together in ...
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ISBN:
(数字)9781461539988
ISBN:
(纸本)9780792392101;9781461367871
oW should coded communication be approached? Is it about prob H ability theorems and bounds, or about algorithms and structures? The traditional course in information theory and coding teaches these together in one course in which the Shannon theory, a probabilistic the ory of information, dominates. The theory's predictions and bounds to performance are valuable to the coding engineer, but coding today is mostly about structures and algorithms and their size, speed and error performance. While coding has a theoretical basis, it has a practical side as well, an engineering side in which costs and benefits matter. It is safe to say that most of the recent advances in information theory and coding are in the engineering of coding. These thoughts motivate the present text book: A coded communication book based on methods and algorithms, with information theory in a necessary but supporting role. There has been muchrecent progress in coding, both inthe theory and the practice, and these pages report many new advances. Chapter 2 cov ers traditional source coding, but also the coding ofreal one-dimensional sources like speech and new techniques like vector quantization. Chapter 4 is a unified treatment of trellis codes, beginning with binary convolu tional codes and passing to the new trellis modulation codes.
Rutgers University launched WINLAB in 1989, just as the communications industry, the Federal government, and the financial community in the United States, were waking up to the growing public appetite for wireless com...
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ISBN:
(数字)9781461540120
ISBN:
(纸本)9780792392187;9781461367949
Rutgers University launched WINLAB in 1989, just as the communications industry, the Federal government, and the financial community in the United States, were waking up to the growing public appetite for wireless communications and to the shortage of technology to feed it. The secret was already out in Europe, where no fewer than three new cordless and cellular systems were progressing from drawing board to laboratory to factory to consumers. In July 1989, the FCC held a well-attended tutorial that turned into a debate over whether second generation British or Swedish technology held the key to mass-market personal communications. Many in the audience wondered whether United States technology was out of the picture. Technology uncertainties are more acute in wireless communications than in any other information service. For example multi-gigabit optical fiber communications have followed an orderly progression from basic science leading to technology, which in turn stimulated standards, and then commercial products. Eventually applications will be found and industry and society at large will reap the benefits. By contrast, the applications of wireless communications are apparent to an eager public. A large market exists but is held in check by a shortage of capacity. The demand has led the cellular industry to formulate standards for advanced systems before the technology is in place to implement them. Everyone holds their breath waiting to observe performance of the first products. Gaps in basic science add to the uncertainty and forestall the resolution of technological debates.
From the Foreword.....;Modern digital signal processing applications provide a large challenge to the system designer. Algorithms are becoming increasingly complex, and yet they must be realized with tight performan...
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ISBN:
(数字)9781461314110
ISBN:
(纸本)9780792397441;9781461286127
From the Foreword.....;Modern digital signal processing applications provide a large challenge to the system designer. Algorithms are becoming increasingly complex, and yet they must be realized with tight performance constraints. Nevertheless, these DSP algorithms are often built from many constituent canonical subtasks (e.g., IIR and FIR filters, FFTs) that can be reused in other subtasks. Design is then a problem of composing these core entities into a cohesive whole to provide both the intended functionality and the required performance.;In order to organize the design process, there have been two major approaches. The top-down approach starts with an abstract, concise, functional description which can be quickly generated. On the other hand, the bottom-up approach starts from a detailed low-level design where performance can be directly assessed, but where the requisite design and interface detail take a long time to generate. In this book, the authors show a way to effectively resolve this tension by retaining the high-level conciseness of VHDL while parameterizing it to get good fit to specific applications through reuse of core library components. Since they build on a pre-designed set of core elements, accurate area, speed and power estimates can be percolated to high- level design routines which explore the design space. Results are impressive, and the cost model provided will prove to be very useful. Overall, the authors have provided an up-to-date approach, doing a good job at getting performance out of high-level design.;The methodology provided makes good use of extant design tools, and is realistic in terms of the industrial design process. The approach is interesting in its own right, but is also of direct utility, and it will give the existing DSP CAD tools a highly competitive alternative. The techniques described have been developed within ARPAs RASSP (Rapid Prototyping of Application Specific SignalProcessors) project, a
This book presents theories and techniques for perception of textures by computer. Texture is a homogeneous visual pattern that we perceive in surfaces of objects such as textiles, tree barks or stones. Texture analys...
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ISBN:
(数字)9781461315537
ISBN:
(纸本)9780792391142;9781461288329
This book presents theories and techniques for perception of textures by computer. Texture is a homogeneous visual pattern that we perceive in surfaces of objects such as textiles, tree barks or stones. Texture analysis is one of the first important steps in computer vision since texture provides important cues to recognize real-world objects. A major part of the book is devoted to two-dimensional analysis of texture patterns by extracting statistical and structural features. It also deals with the shape-from-texture problem which addresses recovery of the three-dimensional surface shapes based on the geometry of projection of the surface texture to the image plane. Perception is still largely mysterious. Realizing a computer vision system that can work in the real world requires more research and ex periment. Capability of textural perception is a key component. We hope this book will contribute to the advancement of computer vision toward robust, useful systems. vVe would like to express our appreciation to Professor Takeo Kanade at Carnegie Mellon University for his encouragement and help in writing this book; to the members of computer Vision Section at Electrotechni cal Laboratory for providing an excellent research environment; and to Carl W. Harris at Kluwer Academic Publishers for his help in preparing the manuscript.
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