A technique to reduce error propagation in M-ary decision feedback equalization

A technique is described for reducing the error propagation resulting from the use of decision feedback equalization in an M-ary, varying system. The technique is applicable when the actual system response varies moderately about a nominal response that can be approximated by a partial response. The decision feedback equalizer (DFE) is supplemented with partial response precoding and detection such that the resulting error propagation is a function of only the difference between the actual system response and the partial response. Simulation results for a system with a nominal response equal to the duobinary partial response are given to illustrate the performance improvement