Kelly Fitzpatrick

Media Defect Recovery Using Full-Response Reequalization in Magnetic Recording Channels

Conventional method for media defect recovery in a low-density parity-check (LDPC) coded magnetic recording channel is erasure decoding. In erasure decoding, read back signal in media defect region is erased and not used in channel detection or iterative decoding. In this paper, a new method based on full-response reequalization, in which media defect corrupted signal is first reequalized to full response then partially used in iterative decoding, is proposed. Simulation results show significant performance improvement over conventional erasure decoding in both non-precoded and preceded channels.

A radix-4 soft-output Viterbi architecture

A new radix-4 soft-output Viterbi architecture is presented, which achieves higher data rates than prior radix-2 SOVA designs. The proposed architecture is also more hardware-efficient than a previously reported radix-4 SOVA architecture. New circuits are presented for the generation of path metric differences, the path comparison unit, and reliability update unit. The presented architecture is suitable for highspeed applications such as magnetic recording, where data rates are currently approaching 3 Gb/s.