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Modem theory. An introduction to telecommunications. (English)
Cambridge: Cambridge University Press (ISBN 978-0-521-78014-8/hbk). xiv, 497~p. (2010).
Digital communication theory (or {\it modem theory}) is that part of communication theory in which digital modulation and demodulation techniques play a prominent role in the communication process, either because the information to be transmitted is digital or because the information is temporarily represented in digital form for the purpose of transmission. The main task of communication theory is the design of efficient waveforms for the transmission of information over band-limited or power-limited channels. Digital communication systems are in widespread use and are now in the process of sweeping away even the time-honored analog communication systems, such as those used in radio, television, and telephony. This insightful book is ideal for senior undergraduate students studying digital communications and is also a useful reference for practising engineers. The general purpose of the book is to give a general introduction to the modulation waveforms and demodulation techniques that are central to the design of digital communication systems. The material in this book consists (for the most part) of selected chapters from {\it Digital Transmission of Information} (published in 1990), which have been rewritten and expanded to fit the needs of a course in modem theory and digital communications. The topics are confined to the modulation layer of communication theory. Waveforms and modulators are studied in Chapter 2 (for baseband channels) and in Chapter 5 (for passband channels). Basic demodulators are developed in Chapters 3 and 6 for baseband and passband channels, respectively. More advanced methods of demodulation for channels with dispersion are studied in Chapter 4. A stronger statement of optimality of the matched filter (introduced in Chapter 3) is deferred to Chapter 7, where it is shown to be part of the maximum-likelihood demodulator for both coherent and noncoherent demodulation in gaussian noise. These first seven chapters contain the central ideas of modulation and demodulation, which are at the core of the theory of modems. The final five chapters then go deeper into the subject by developing some of the other topics needed to round out the foundations of the theory of modems. Chapter 8 treats methods of synchronizing the transmitter and the receiver so that they have the same time reference. Next two chapters discuss methods of coding for communication channels to control errors. Chapter 9 discusses codes designed for an additive noise channel, Chapter 10 discusses codes designed for a discrete channel, usually binary. Finally, Chapters 11 and 12 advance the theory beyond the simple linear channel studied in most of this book. In the end of any chapter there are many exercises to test the reader.
Reviewer: Zlatko Varbanov (Veliko Tarnovo)
Classification: M55 P25 R15
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