THE BOOK Digital Control System Analysis and Design by Charles L. Phillips and H. Troy Nagle, Jr. is a good and modern book on discrete-time systems and its microprocessor implementations. Its 550 pages contain nearly all that a control engineer needs in practice. The classical approach using z-transforms, bilinear wtransforms and digital transfer functions as well as the effects of sampling and reconstruction when entering or leaving the computer by ADC or DAC are dealt with in sufficient detail.
These methods already described in the "old" books of Jury, Rassazini, Kuo, Tou and others have lost nothing of their usefulness. But also the "modern" approach using state-space description methods for linear optimal control and state estimation by observers is not forgotten. About 350 pages of the book are devoted to the subjects mentioned so far. The remaining part of the book deals with digital filters and methods to implement these filters with microprocessors. Effects of quantization and signal scaling with the influence of the chosen filter structure on the accuracy due to these effects are described. The structure of many microprocessors is given and their performance is compared. Many examples of programmes in assembly language are given. The Appendix contains a number of computer programs written in BASIC.
The book hardly contains anything about stochastic signals, which is a pity. A little extension describing the relation between autocorrelation functions, power density spectra and variance of discrete-time signals would have been useful and of practical importance at various points as will be shown here after. The following part of this review will deal with various specific points.
The book introduces the bilinear w-transform as w = (T/2),(z -