Digital signal processing algorithms for a phase shift keyed modem

Modems for digital communication links have been traditionally implemented using analogue techniques for the operations such as filtering, mixing, squaring etc. Advances in digital electronics and programmable Digital Signal Processors have now enabled discrete time processing of signals in all but very high bit rate situations. Advantages of this approach include increased flexibility, better repeatability (due to freedom from drift, offsets etc.) and the greater range of processing operations and structures available. Some descriptions of satellite modems using discrete time processing are now available e.g. (Heegard, 1978), (Imbeaux, 1986).