Patent ID: 6611397
Filing Date: 2003-08-26
Classification: G11B

Abstract:
In a disc drive having a rotatable disc on which servo data are stored to enable a servo circuit of the disc drive to position a head relative to the disc, the servo data including a position field comprising a plurality of burst patterns from which burst signals are transduced, the servo circuit sampling and combining the burst signals to generate a position error signal indicative of the position of the head with respect to a corresponding track, a method for detecting a defective burst pattern comprising steps of:(a) determining a sequence of servo burst amplitude samples indicative of peak amplitudes of a servo burst signal obtained from a selected burst pattern; (b) determining a sequence of difference values in relation to differences between absolute values of successive pairs of the servo burst amplitude samples from step (a); (c) comparing the sequence of difference values to a defect threshold; and (d) identifying the selected burst pattern as defective when at least one of the difference values exceeds the defect threshold.