An introduction to parametric digital filters and oscillators. Mikhail Cherniakov, Wiley: England, 2003. No. of pages: xv + 245. Price: £76.00. ISBN 0‐470‐85104‐X
Yogeshwarsing Calleecharan · International Journal of Adaptive Control and Signal Processing · 2008
Based on much of his own research work and from long years of experience in the field of linear non-adaptive time-variant systems, the author has succeeded in writing a monograph presenting the concepts involved in a unified way that complements traditional books on signal processing. Surprisingly enough, this book appears to be unique in the literature in its contents. With lots of mathematics, the book is not a light reading despite sincere efforts from the author to make it accessible to advanced students in signal processing. To really appreciate the concepts laid, a good background in linear systems theory, adaptive signal processing, and filter design is essential. Chapter 1 is the first of seven chapters making up the textbook. Discussions include discrete linear signals and systems, important DSP concepts, and both FIR and IIR filters. Even someone familiar with these traditional topics is advised to go through this chapter since much of his/her understanding as he or she will continue reading the book relies on catching the author's style as from the onset. The rest of the book is split into three parts with Chapters 2 and 3 forming Part 1, Chapters 4 and 5 composing Part 2, and finally Chapters 6 and 7 making up Part 3. The themes of the various parts are as follows: Part 1—Linear Discrete Time-Variant Systems, Part 2—Parametric Systems, and lastly Part 3—Digital Parametric Oscillators. Chapter 2 is important as it sets the mood for the book and it presents the main characteristics of linear time-variant systems. The author has been successful to draw an analogy with conventional linear time invariant systems. The concept of the generalized transfer function is introduced as being significant in the treatment of time-varying systems. Other interesting discussions cover the problematic choice of a proper sampling frequency, the filtering of random signals through time-variant systems, and possible systems connection structures. Chapter 3 discusses periodically time-variant discrete systems. The treatment is inline with the previous chapter though now a more specific class of systems is studied. The main difference from Chapter 2 is that of the stability problem. To this end, the second Liapunov method is introduced. Stability of second-order systems and stochastic systems enjoys substantial coverage. Part 2 of the book starts with Chapter 4, which deals with parametric filters analysis. These parametric filters are systems that behave as frequency-selective circuits. Under some circumstances, their characteristics are not different from time-invariant systems. Discussions center around the family of recursive parametric filters. An approximate analysis method of such systems closes the chapter. Chapter 5 presents some design studies for parametric systems. It is noted that the complexity of time-variant systems does not lead to universal design methods. A few examples incorporating the consideration of quantization effects, which can lead to instability problems, raise the value of the discussions. Combinational components interference is addressed. Chapter 6 begins the last part of the textbook and it focuses on digital parametric oscillators. These digital resonators, investigated only by the author in the literature, are important tools for signal processing of periodically linear time-variant systems. Liapunov stability theory accompanies the discussions. Material in this chapter includes regions of parametric oscillations, system modeling, and transients in parametric oscillators. This chapter is worth re-reading as many aspects are examined that are a prerequisite for the next chapter. Chapter 7 presents parametric oscillators in steady-state mode. Together with Chapter 6, this last chapter covers many practical issues that consolidate the textbook. Several examples are considered but some of them come with thin discussions. However, the author is to be commended to write about diverse applications that will also attract practicing engineers. The author has certainly been able to show that parametric digital filters can lead to superior results over conventional filters in some applications. Though carefully written with a motivating preface and plentiful of references throughout the text, the textbook can nevertheless be improved. Firstly, examples are not numerous in some chapters and this coupled to the lack of exercises for the reader may unfortunately pressure students to build their understanding just around the examples given. Secondly, to enhance the value of a future edition, the author can consider making available the computer codes so that the reader can reproduce the examples in the text. Finally, in order to save space, the author has abbreviated many terms and while he has cared to put a list of abbreviations at the end of each chapter, the presence of too many abbreviations at times unfortunately tends to hamper the smooth reading of a text that is already abounded with new concepts.