Abstract
We propose a new PRML algorithm for the digital recording systems with d≧1 channel code. First, the reproducing signals are equalized to the PR1 characteristic and detected 2-level bit-by-bit. Then the state transition path are limited to four. Using this limitation, we can realize Viterbi decoder for EPR4ML systems with only 2-state. The proposed decoder can be realized easily as high speed circuit with less circuit. The performance of this decoder is a little better than the conventional decoder.
