13.1 Introduction

During the period 1975 1985 many instruments designers recognised the value of microprocessors in the design of instruments. Digital storage scopes, function generators, and frequency counters, etc., were the early families of instruments that made use of the microprocessor subsystems. High performance analogue oscilloscopes were another classic example of use of microprocessor subsystems for add-on features and performance. FFT analysers were yet another kind of instruments to use digital signal processors (DSPs).

Early generations of 4- and 8-bit microprocessors have evolved into 16-, 32- and 64-bit components with complex instruction set computer (CISC) or reduced instruction set computer (RISC) architectures. DSPs can be considered as special cases of RISC architectures or sometimes parallel developments of CISC systems to tackle real time signal processing needs. Over the past two decades, the field of digital signal processing has grown from a theoretical infancy to a powerful practical tool and matured into an economical yet successful technology. At the early stages, audio and the many other familiar signals in the same frequency band appeared as a magnet for DSP development. The 1970s saw the implementation of signal processing algorithms especially for filters and fast Fourier transforms (FFT) by means of digital hardware, developed for the purpose. Early sequential program DSPs are described in Reference 1. In the late 1990s the market for DSPs was mostly generated by wireless, multimedia and several other applications. According to industry estimates, by the year 2001, the market for DSPs had been expected to grow up to...