TABLE OF CONTENTS Digital systems are all the rage these days. Mention that a consumer product is digital and it is sure to sell. For home computers, MP3 players, mobile telephones, DVD players and surround sound systems, sales have never been better. Why is this? What does digital mean anyway? Is it true that digital implies high quality, better than we could get from traditional analog techniques? The answer to the last question is yes, but why this is so may not always be obvious. And where does digital signal processing (DSP) sit in all of this? If DSP involves the processing of digital data, surely everything that we do on computers can be said to be DSP including, for example, word processing or web browsing? Well not really. Most practitioners would agree that, strictly speaking, DSP involves manipulation of signals that have their origins in the analog world. Such signals may be produced for example, by video, audio, radio telemetry, radar, thermal, magnetic or ultrasonic sensor systems, to name but a few from a truly enormous range of devices and instruments. The point here is that the signals are originally analog and continuous in nature to start with (do not worry too much about these terms just yet just think about a microphone. It produces a continuous electrical signal whose magnitude is proportional to the intensity of sound it detects).
The problem with artificial definitions of this kind is that there are always grey...
