An adaptive IIR equalizer for nonminimum-phase channels

An adaptive IIR equalization method for nonminimum-phase channels is presented. In order to ensure the stability of the IIR equalizer, we propose a novel way to obtain a minimum-phase equalized channel from a nonminimum-phase channel. A FIR direct equalizer is followed by an all-pole IIR indirect equalizer to form an optimal equalizer structure. The minimum-phase equalized channel is directly inverted by the indirect equalizer and the remaining part of the channel is handled by the direct equalizer. The Routh-Hurwitz criterion is introduced for verifying that the directly-equalized channel is minimum phase. With the same number of taps, the proposed IIR equalizer performs much better than conventional FIR equalizers in terms of residual MSE.