Performance Analysis of Modified PRML Channels for Perpendicular Recording Systems

Abstract We designed an optimal partial-response maximum-likelihood (PRML) channel for a high-density perpendicular magnetic recording system using a single-pole-type (SPT) recording head and a double-layered medium. The first key feature is a generalized PR (GPR) channel to achieve nearly optimal noise-whitening filtering for the desired recording channel. The second key feature is a class-III-based GPR (GPR3) channel with suppressed low-frequency components to provide a better match with a DC-distorted channel. We confirmed that 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.