Performance analysis of modified PRML channels for perpendicular recordingsystems

We designed an optimal partial-response maximum-likelihood (PRML) channel f or a high-density perpendicular magnetic recording system using a single-po le-type (SPT) recording head and a double-layered medium. The first key fea ture is a generalized PR (GPR) channel to achieve nearly optimal noise-whit ening filtering for the desired recording channel. The second key feature i s a class-III-based GPR (GPR3) channel with suppressed low-frequency compon ents to provide a better match with a DC-distorted channel. We confirmed th at for the media-noise-dominant channel, the new GPR3 channel improved the SNR by more than 1.8 dB compared to other types of PRML channels. (C) 2001 Elsevier Science B.V. All rights reserved.