Adaptive continuous-time forward equalization for DFE-based disk-drive read channels

A continuous-time forward equalizer for use with decision-feedback equalization (DFE) is proposed which exploits correlation between the disk-drive readback signal and its derivative. The performance of the one-zero equalizer is derived for an infinite-length DFE and a 4-tap DFE and is shown to perform as well as a 5-tap finite-impulse-response (FIR) filter for PW/sub 50/=2 T. Finally a possible adaptive implementation is presented along with a simulation of its convergence with the sign-sign least-mean-square (LMS) algorithm. The proposed equalizer will provide a large savings in die area and power over digital methods.