Patent ID: 7864482

Claim:
A disk drive comprising: a disk; a head; a voice coil motor (VCM) for actuating the head over the disk; and control circuitry comprising a notch filter for generating a VCM control signal, wherein a notch of the notch filter comprises a frequency, a width, and a depth, the control circuitry further operable to calibrate the notch filter by: initialize the width of the notch to a first width setting and measure a quality metric of the notch filter; when the quality metric indicates poor performance, sweep the depth of the notch over a range of settings for the first width setting; when the depth of the notch filter reaches a last setting and the quality metric continues to indicate poor performance, increase the width of the notch to a second width setting and re-measure the quality metric of the notch filter; and when the quality metric continues to indicate poor performance, sweep the depth of the notch over the range of settings for the second width setting.