Optimum filter design for partial-response class-IV transmission systems

The design of a mixed digital/analog transmit filter and a variable analog receive filter for partial-response class-IV signaling over metallic cables is discussed. Optimum filters are analytically determined for maximum cable length and additive Gaussian noise. Since the transfer function of the overall channel is given, these filters are independent of crosstalk. The optimum filter characteristics are approximated by those of single realizable filters. A simple analog equalizer section with independently controllable bandwidth and gain parameters is optimized by simulated annealing so that it could best compensate for variations of cable length when used as part of the receive filter. Simulated annealing is also employed to determine the remaining fixed section of the receive filter and the analog transmit filter. The digital section of the transmit filter is designed to achieve precise signal shaping over the considered range of cable lengths