Book Review: Underwater Acoustic Systems:

display. Unless precautions are taken, the process of analogue-to-digital conversion (ADC) will introduce 'noise' errors. Various types of ADC, sampling, and the problem of 'aliasing' are described. Chapters 9 and 10deal with pulsed signals and transients, and how to determine their magnitudes, and their time of occurrence. They describe such techniques as filtering, sampling, boxcar integration, peak and valley detectors, lock-in amplifiers, and autocorrelation methods. Chapter II is new to the second edition. It covers the measurement of the frequency of a pulsed signal, which is closely related to the problem of measuring its time of occurrence, dealt with in the preceding chapter. The book is somewhat theoretical, and its content is conceptually difficult and rather mathematical. It is aimed at postgraduate and third-year, undergraduate electronics engineers, and those postgraduate instrumentation specialists, who may not be electronics engineers, but who do require some advanced knowledge as members of a specialist team. The subject matter is not easy to understand. In order to help the reader, therefore, this new edition includes a set of thirteen tutorial questions, whose numerical answers are given. The questions are intended to span the range of topics contained within the book, in order to consolidate the reader's understanding of the material presented. The text does not include any worked examples, or references, at all, but it should provide a good deal of theoretical background to an important and complex subject-area. BRIAN M. SHAW, Division of Electrical and Electronic Engineering, HatfieldPolytechnic