Performance improvement of Viterbi decoding for FM recording code

In high-density recording, the performance of the conventional Viterbi decoder for FM recording code is degraded by the influence of the correlation between samples of the noise at the discrimination point. A decoding method is therefore proposed which uses a Viterbi decoder whose form assumes a simple Markov process for the noise at the discrimination point. The error probability of this method is obtained by computer simulation and the performance is compared with that of a conventional decoder. The results show that a large improvement in performance is achieved