Chapman M.J., Goodall D.P., Steele N.C. Signal Processing in Electronic Communications

Horwood Publishing, 1997. — 305 p.Communication is the process by which information is exchanged between human beings, between machines, or between human beings and machines. Communication Theory is the theory of the transmission process, and the language of this theory is mathematics. This book sets out to explain some of the mathematical concepts and techniques which form the elements and syntax of that language, and thus enable the reader to appreciate some of the results from the theory.
In some ways, the degree of evolution of a nation or state may be measured by the sophistication of its communication processes, particularly those based on electronic means. Within the lifetime of one of the authors, the telephone has become an everyday means of communication, and television has moved from a rarely seen novelty to the means of mass entertainment. Instantaneous communication over long distances, across continents or oceans, by voice or text has become an everyday requirement in many walks of life. More recently, the internet has provided a new dimension to the way many of us work. Electronic mail is not only an indespensible tool for collaborative research, it is a means by which colleagues, perhaps in different countries, communicate on a day-to-day basis. The wider resource of the so-called world-wide-web gives access to a mass of data. Perhaps the major problem which faces us at the time of writing is how these data can be turned into information efficiently, but that is a debate for a different forum!
All these forms of communication are conducted by the transmission of electronic signals using an appropriate method and this book concentrates on the description of signals and the systems which may be used to process them. Such processing is for the purpose of enabling the transmission of information by, and the extraction of information from, signals. Over the last few years, the unifying concepts of signals and linear systems have come to be recognised as a particularly convenient way of formulating and discussing those branches of applied mathematics concerned with the design and control of 'processes'. The process under discussion may be mechanical, electrical, biological, economic or sociological. In this text, we consider only a restricted subset of such processes, those related to communication by electronic means. There are several first class treatments of the general field of signals and linear systems and indeed, some specifically related to communication theory. However, in many cases, the haste to discuss the engineering applications of the material means that the mathematical development takes second place. Such a treatment may not appeal to, or even be readily accessible to those whose first subject, or interest, is mathematics, and who thus may not be able to supply the necessary engineering insight to follow the discussion easily. This book is aimed in part at such readers who may wish to gain some understanding of this fascinating application area of mathematics.
We are also aware from our teaching experience that many of our engineering students (possibly more than is commonly acknowledged!) also appreciate such a development to complement and support their engineering studies. This book is also written for this readership. It is interesting to recall that, whilst the need for engineers to become competent applied mathematicians was widely recognised in the recent past, this need is not so often expressed, at least in some countries, today. It will be interesting to compare future performance in the field of design and innovation, and thus in economic performance, between countries which adopt different educational strategies.
The subject matter which is included within the book is largely self-contained, although we assume that the reader will have completed a first course in mathematical methods, as given for engineering and computer science students in most UK Universities. The style adopted is an attempt to capture that established for textbooks in other areas of applied mathematics, with an appropriate, but not overwhelming, level of mathematical rigour. We have derived results, but avoided theorems almost everywhere!
Many books on applied mathematics seem to concentrate almost exclusively on the analysis of 'given' systems or configurations. In producing this text, we have attempted to demonstrate the use of mathematics as a design or synthesis tool. Before such a task may be undertaken, it is necessary for the user or designer to achieve a considerable degree of experience of the field by the careful analysis of the relevant types of system or structure, and we have attempted to provide a suitable vehicle for this experience to be gained. Nevertheless, it has been at the forefront of our thinking as we have approached our task, that the aim of many readers will eventually be the production of network or system designs of their own. We cannot, in a book such as this, hope to give a sufficiently full treatment of anyone topic area to satisfy this aim entirely. However, by focusing on the design task, we hope to demonstrate to the reader that an understanding of the underlying mathematics is an essential pre-requisite for such work.
Most of the material has been taught as a single course to students of Mathematics at Coventry University, where student reaction has been favourable. The material, to a suitable engineering interface, has been given to students of Engineering, again with encouraging results. Engineering students have generally acknowledged that the course provided an essential complement to their Engineering studies. Many of the concepts considered within the book can be demonstrated on a PC using the MatLAB package, together with the various toolboxes. In Appendix B, we give some 'm' files, with application to the processing of speech signals.Signals and linear system fundamentals
System responses
Fourier methods
Analogue filters
Discrete-time signals and systems
Discrete-time system responses
Discrete-time Fourier analysis
The design of digital filters
Aspects of speech processing
A: The complex exponential
B: Linear predictive coding algorithms
C: Answers to the exercises