Viterbi detection for partial response channels with colored noise

Summary form only given. A method proposed previously by Dorfman and Wolf (see IEEE J. Select. Areas in Commun., vol. 19, p. 662-667, Apr. 2001) for combating the Thermal Asperities (TA) required running two Viterbi detectors in parallel - one matched to an EPR4 channel (target) and the other to a PR5 channel. A PR5 channel was formed by passing the EPR4 channel output through a 1-D filter preceding the PR5 matched detector and was shown to be superior to EPR4 in the presence of TA´s, but 2.7 dB worse than EPR4 with Gaussian noise only. The reason for this deficiency is that the 1-D filter colors the noise substantially. In this paper an approach is proposed to improve Gaussian performance of the PR5 detector by taking the noise correlation into account. It is also shown that EPR4 channel performance can be improved by the same method.