A Study of Class I Partial Response Signaling for Magnetic Recording

Using a semianalytic technique based on the work of Agazzi and Seshadri, we compare the performance of PR1, PR4, and EPR4 partial response schemes on a magnetic recording channel. The technique includes the effect of imperfect equalization and, in the PR4 case, the effect of employing two interleaved Viterbi detectors. Assuming the Lorentzian channel model and superposition, we use this technique to compare these signaling schemes at medium and high recording densities. It is observed that, even with the trivial DC-free code employed, PR1 is superior to PR4 at recording densities beyond about Sc = 2.4 and superior to EPR4 beyond about Sc = 2.9. In addition, PR1 lends itself to difference metric Viterbi detection. Our analytical results are supported by computer simulations.