An adaptive noise-predictive decision-feedback equalizer for the magnetic recording channel

An adaptive noise-predictive decision-feedback equalizer (DFE) for a read channel is described. This decision-feedback equalizer uses a recursive filter to whiten the noise at the input of the decision slicer, increasing the detection signal-to-noise ratio. The noise-predictive filter works in conjunction with the DFE to cancel postcursor intersymbol interference. A scheme for adapting the finite-impulse-response forward equalizer, feedback equalizer, and noise-predictive filter is presented. This read channel can perform better than a DFE with a FIR or an all-pass forward equalizer.