Decision feedback equalization

Design equations are presented for optimum decision feedback equalizers, with emphasis on the minimum mean-square error criterion with and without a zero force constraint. Fixed transmitter, optimum receivers, and joint optimum systems were considered. Minimum probability of error receivers was considered and known performance bounds were given along with a comparison with maximum likelihood sequence detection. Using the coaxial cable as an example of a highly dispersive channel, it was shown that the performance bound is somewhat weak and there is considerable advantage in using a DFE over a linear equalizer.