Non-linear equalizers having an improved tolerance to noise

The paper describes a simple development of a conventional non-linear equalizer which involves only changes to the equalization process itself and can, under certain conditions, give a useful improvement in tolerance to additive white Gaussian noise. The technique is particularly effective when binary data-symbols are transmitted and there is severe amplitude distortion in the received signal. The optimum design of the modified equalizer together with an interesting sub-optimum arrangement, for the application of greatest practical interest, are derived first and then approximate estimates of their tolerances to additive white Gaussian noise. Finally, results are presented of computer-simulation tests, with binary signals transmitted over various channels in he presence of additive white Gaussian noise, and the results are compared with the corresponding theoretical predictions.