Equalization with an H∞ criterion

We study the problem of linear equalization from an H^∞ point of view and parameterize, in closed form, all possible H ^∞-optimal equalizers. The results indicate an interesting dichotomy between minimum phase and non-minimum phase channels: for minimum phase channels the best causal equalizer performs as well as the best noncausal equalizer, whereas for non-minimum phase channels, causal equalizers cannot reduce the estimation error bounds from their a priori values