WHAT IS SIGNAL PROCESSING?
1.1 CHAPTER OBJECTIVES
On completion of this chapter, the reader should
1. be able to explain the broad concept of digital signal processing (DSP);
2. know some of the key terms associated with DSP; and
3. be familiar with the conventions used in the book, both mathematical and for code examples.
Signals are time-varying quantities which carry information. They may be, for example, audio signals (speech, music), images or video signals, sonar signals or ultrasound, biological signals such as the electrical pulses from the heart, communications signals, or many other types. With the emergence of high-speed, low-cost computing hardware, we now have the opportunity to analyze and process signals via computer algorithms.
The basic idea is straightforward: Rather than design complex circuits to process signals, the signal is first converted into a sequence of numbers and processed via software. By its very nature, software is more easily extensible and more versatile as compared with hard-wired circuits, which are difficult to change. Furthermore, using software, we can build in more “intelligence” into the operation of our designs and thus develop more human-usable devices.
A vitally important concept to master at the outset is that of an algorithm: the logical sequence of steps which must be followed in order to generate a useful result. Although this definition is applicable to general-purpose information processing, the key ...