A reduced-complexity trellis search decoding algorithm for extended class IV partial response systems

Modeling the magnetic recording channel as a class IV partial response system (PR4) combined with maximum likelihood detector has been shown to result in great improvements in linear storage density over the traditional peak detection method. The storage density can be further improved if the channel is modeled as an extended class IV partial response system (EPR4). The authors propose a novel recursive detection scheme for an EPR4 system which is computationally efficient when compared to the Viterbi algorithm, which achieves near-optimum performance but has substantially reduced computational and storage requirements. They present the model used and describe the technique in detail. The decoding algorithm can be applied to digital magnetic recording. It is shown that the performance of the algorithm is very close to Viterbi reception