PERFORMANCE COMPARISON OF DETECTION METHODS IN MAGNETIC RECORDING

This paper compares various detection schemes suitable for magnetic recording in terms of their effective signal-to-noise ratios. We show that at high densities the performance of conventional detectors—peak detector, threshold detector with partial response equalization, decision feedback equalizer, and Viterbi algorithm (VA) detector tuned to a linearly truncated channel—falls far below the optimum performance that can be achieved by the maximum-likelihood sequence detector (MLSD). It is shown that while implementing the full MLSD is clearly out of the question for high densities with severe intersymbol interference (ISI), there exists an efficient detection scheme which achieves an excellent compromise between hardware complexity and detection performance. This scheme, which we call the fixed-delay tree search with decision feedback (FDTS/DF), combines a fast and efficient tree-search algorithm with a decision feedback equalizer to cancel out a portion of ISI without noise enhancement. It is well-suited for run-length-limited (RLL) systems and attains performance close to that of MLSD while maintaining reasonable implementation cost and processing requirements. © 1990 IEEE