In this work, we study a receiver for a high density recording system and compare it with the PRML recording system. In the receiver, the playback signal of a high density recording system is equalized to a higher-order partial response (PR) target. Also, a reduced-state Viterbi algorithm, called the generalized Viterbi algorithm (GVA), is used for detecting the PR system. In the GVA, the states are grouped into L subsets or lists and the best S paths in each list are selected for extension. Simulation results demonstrate that a coding gain over the PRML system can be obtained even for the receiver with less complexity than that of the PRML system.
