Post Compensation for Nonlinear Distortions in PRML Recording Channel

The performance of the PRML recording channel is degraded due to nonlinear distortions introduced in the recording or reproducing processes for high density recordings. Although the maximum likelihood sequence detector (Viterbi detector) might be applied to the channel including these nonlinearities, the Viterbi detector suffers from hardware complexity since the interleaved two-state trellis diagram for 1-D partial response channel does not sufficiently describe the PRML channel including nonlinearities. In this study, a post compensation for the PRML recording channel including nonlinearities is presented. The nonlinear effects are compensated for after playback and the interleaved two-state trellis for 1-D partial response channel is used to recover data from compensated signal. Simulation results indicate that the performance can be enhanced with a slight increase in hardware complexity.