Patent ID: 6216249
Filing Date: 2001-04-10
Classification: G11B,H03M

Abstract:
A sampled amplitude read channel for reading data recorded on a disk storage medium by detecting an estimated binary sequence from a sequence of discrete-time sample values generated by sampling an analog read signal emanating from a read head positioned over the disk storage medium, the sampled amplitude read channel comprising:(a) a sampling device for sampling the analog read signal to generate the discrete-time sample values;(b) a timing recovery circuit, responsive to the discrete-time sample values, for generating synchronous sample values x.sub.k ; and(c) a trellis sequence detector for detecting the estimated binary sequence from the synchronous sample values x.sub.k, the trellis sequence detector comprising a branch metric calculator for calculating a simplified branch metric by effectively adding a positive offset to a Euclidean branch metric to make it a multiple of a scaler and dividing by the scaler, thereby reducing a number of bits used to represent the simplified branch metric.