A dual noise-predictive partial response decision-feedback equalizer for RLL(1,x) coded perpendicular magnetic recording channels

Partial response maximum likelihood (PRML) is a powerful and indispensable detection scheme for perpendicular magnetic recording channels. The performance of PRML can be improved by incorporating a noise prediction scheme into branch metric computations of the Viterbi algorithm (VA). However, the systems constructed by VA have shortcomings in the form of high complexity and cost. In this connection, a new simple detection scheme is proposed by exploiting the minimum run-length parameter d=1 and is extended to dual-detection scheme for improving the bit-error rate (BER) performance. Simulation results show that the proposed scheme has a comparable performance to noise-predictive maximum likelihood detector with less complexity when the partial response (PR) target is (1,2,1).