Golden insights into a black art

Over the past decade degree courses in electronic engineering have incorporated a major shift towards digital systems and software engineering. To avoid excessive material, course designers have tended to exclude most things associated with electromagnetics and "black-art" high-frequency electronics.

These subjects are often conceptually more difficult and sometimes demand a level of mathematical treatment increasingly unpopular with undergraduates. However there is strong industrial demand for graduates with a knowledge of high-frequency electronics, generated, not least, by the significant growth in wireless communications. This book by Jon Hagen should prove to be an invaluable text to support undergraduate courses in radio-frequency circuits.

The author is director of laboratory operations at the National Astronomy and Ionosphere Centre at Cornell University in the United States. He has many years' industrial and academic experience in radio-frequency circuits and systems and this practical experience is immediately evident on reading his book. It is intended to provide an introduction to radio-frequency circuits and assumes only a knowledge of elementary electronics and circuit analysis.

Originally used to support a one-semester course at Cornell, its primary intended market is junior and senior courses in electrical engineering, though it could also be used as a basic reference for engineers in industry.

Hagen's book is written in the same style as the highly successful The Art of Electronics by Paul Horowitz and Winfield Hill. (The popularity of this book can be judged by its availability on the shelf at any branch of W. H. Smith. How many other advanced textbooks in technology can claim this distinction?) They also share a common publisher, Cambridge University Press. Both books are distinctive in that they emphasise practical design knowledge based on years of experience by the authors. This is a refreshing change from many conventional texts on electronic circuit design which often degenerate into extended algebraic manipulation with minimal interpretation or explanation of actual circuit design. As with The Art of Electronics, this text is a goldmine of information and practical insights into circuit design.

The coverage is extensive, including chapters on transmission lines and impedance matching, linear amplifiers and filters, frequency converters, power supplies, modulation techniques and oscillators. Each chapter is concise (typically ten pages) including an introduction, main text and end-of-chapter problems. Subsequent chapters discuss phase-locked loops, frequency synthesisers, switching converters and hybrid couplers. The very important topic of amplifier noise is treated in two chapters, followed by transformers, wave-guide circuits and antennas and wave propagation. The author recognises that students tend to be more experienced in digital than analogue techniques. This is reflected in the relatively short treatment of switching modulators and direct digital synthesisers compared with the detailed discussion of analogue aspects. Application areas considered include television systems, radar pulse modulators, radio and radio astronomy and radio spectrometry. A final chapter is devoted to laboratory test equipment.

Although each chapter concludes with several problems, no numerical answers or solutions are provided. This is disappointing since the recent trend in electronic engineering texts has been to provide fully worked solutions to students (and more importantly to instructors) via the Internet. Another disappointing feature is the minimal use of computer-aided design for analysis and circuit simulation. Some Q.Basic programs are included but most textbooks in electronic circuit design now use simulation packages (eg Spice) to enhance student understanding and design.

However, despite the above minor reservations, this is an outstanding book which should be widely used as an undergraduate text.

Philip Mars is professor of electronics, University of Durham.