Apparatus and method for correcting a read signal in a disk drive system

Abstract

In a disk drive system, a circuit reduces the deterioration of the S/N ratio and corrects the position of a peak in a read signal to an accurate position. In one embodiment, a circuit senses the threshold levels corresponding to the magnitudes of three consecutive peaks of a read signal. A comparator obtains the direction of shift of the centrally positioned peak with respect to a reference position from the relationship of the magnitudes of the three consecutive peaks. The comparator outputs a pulse representing the direction of shift to a FIFO buffer. A delay circuit outputs a plurality of pulses. The pulses are shifted by an amount corresponding to a threshold level. A multiplexer selects a pulse to output from the delay circuit based on the direction of shift that was output from the FIFO buffer and based on the difference detected by an amplitude detection circuit. In an alternative embodiment, the correction circuit is implemented using a microprocessor.