EPR4 VITERBI DETECTOR

The Viterbi detector performs maximum-likelihood (ML) sequence estimation on the equalized sample values. The output of the Viterbi detector is the allowed (ideal) EPR4 sampled waveform sequence which minimizes the sum-of-squared errors between itself and the sample sequence from the equalized readback signal. This is determined by considering exhaustively all allowed EPR4 sampled sequences during the data field.

FEATURES

• performs maximum-likelihood (ML) sequence estimation on the equalized sample values.
• the output of the Viterbi detector is the allowed (ideal) EPR4 sampled waveform;
• implementation of the ML detector is based on the block diagram of Figure 1; all operations shown in this figure are applied to the trellis diagram in Figure 2.
• the best sequence is selected by suitably comparing all candidate sequences using recursive computations based on the ADD-COMPARE- SELECT (ACS) units.

SYSTEM OVERVIEW