Linear and non-linear transversal equalizers for baseband channels

Various design techniques are described for conventional equalizers that use transversal filters. Two different arrangements are studied. In the first, the equalization process is located at the receiver, and in the second it is shared between the transmitter and receiver. The optimum linear and non-linear equalizers, together with some suboptimum designs, are described for each of the two arrangements, and the tolerances of the different systems to additive white Gaussian noise are compared for different values of the sampled impulse-response of the channel. It is assumed that a serial digital baseband signal is transmitted over a linear baseband channel whose sampled impulse-response is known. The practical implementation of the filters and techniques for the automatic or adaptive adjustment of the equalizer tap gains are not considered. The aim of the paper is to clarify the basic principles of the various equalization processes studied and to demonstrate some of the interesting relationships that exist between the different equalizers.