Low-complexity signal processing for ISI channels

We present-a low-complexity soft detection and soft decoding magnetic disk drive read channel with a modified soft-output signal space detector (S³D) which uses 3D-110 equalization and an error/erasure decoding Reed Solomon (RS) code. The detector determines max-log reliability information for intersymbol interference (ISI) channels with stationary white and colored noise. It can be implemented with only little additional hardware compared to the ordinary signal space detector. The erasures of the RS code are determined by the soft information and by an additional inner error detecting code (EDC) which is matched to the error patterns of the S³D. The proposed system permits an improvement of the decoding performance in practical hard disk applications.