Equalizer performance in a magnetic recording channel with asymmetric response

The performance of linear and decision-feedback equalization and maximum-likelihood sequence estimation techniques is evaluated for a digital magnetic recording channel having an asymmetric pulse response. In particular, the authors evaluate the performance of linear and decision-feedback equalizers which shape the signal step response at the output of the equalizer into responses of the form (1+D)ⁿ , where n is a nonnegative integer. Alternatively, partial responses of length L that minimize the mean-square-error at the output of a linear equalizer are derived and their performance is compared to the (1+D)ⁿ equalizers. Comparisons were made with the performance of equalizers in a magnetic recording channel having a symmetric pulse response