Q. What do you mean by Signal Processing?

The essential feature of communication, control, computation, and instrumentation systems is the processing of information. Because of the relative ease and flexibility of processing and transmitting electrical quantities, usually the information obtained from a nonelectrical source is converted into electrical form. An electric signal is a voltage or current waveform whose time or frequency variations correspond to the desired information. The information-bearing signals are processed either for purposes of measurement in an instrumentation system, or for transmitting over long distance in a communication system. All such systems, regardless of their particular details, share certain basic concepts and common problems.