The purpose of this book was to establish the principles of digital signal processing, and to explain the steps by which these principles may be expressed in practical, realisable terms, for both off-line and real-time processing environments. For this reason, the treatment has emphasised the foundations of the discipline (hence the title). In this context, subjects that merit the greatest attention are linear systems, Fourier analysis, convolution, signal acquisition and filtering; the reader will judge whether or not the pedagogical objectives in exploring these themes have successfully been achieved. Although in Chapter 1 we commenced with a discourse on the nature and definitions of DSP and the many areas in which it is exploited, detailed coverage of application areas has been deliberately avoided for instance, we have not discussed how DSP is used for signal compression, decompression, voice band coding, musical technology and so on. To do so would have made the length of the book excessive; a proper account of each of these areas deserves a text in its own right. In this concluding chapter however, it would be appropriate to speculate on the future of DSP technology and how it will be applied over the coming years.

With the ubiquitous deployment of signal processing, it is easy to forget that until the 1970s, there really was no such thing as DSP. Many texts, both paper-based and in electronic form on the internet, discuss future trends in this area of semiconductor technology. Indeed, such forecasting is a vital...