MULTICHANNEL SIGNAL-PROCESSING FOR MULTIPLE-HEAD DIGITAL MAGNETIC RECORDING

This paper analyzes the performance of a multiple-head, digital, magne tic recording system using multichannel signal processing theory. A mu lti-input, multi-output (MIMO) channel that models the multiple-head r ecording process provides the basis for this analysis. This model char acterizes the write process, the read process and both electronics and media noise. In particular, the model accounts for side fringing betw een a read head and adjacent tracks; side fringing is a major cause of intertrack interference that is often neglected during signal process ing analysis. Optimal decision feedback and partial response equalizer s for the MIMO channel are derived using a minimum mean-squared error criterion. Numerical evaluations show that a magnetic recording system comprising a multiple-head array and equalizer combats intertrack int erference much better than does the corresponding single-head system. As a result, the multiple-head system achieves a gain of up to a facto r of 3.5 in radial density over the single-head system for a fixed val ue of maximum head misalignment.