Patent ID: 7492675
Filing Date: 2009-02-17
Classification: G11B

Abstract:
1. A method of calibrating a notch filter in an optical disk drive's digital servo system, comprising: digitizing sensor signals from an optical pickup unit within the optical disk drive; within a digital signal processor, calculating a focus error signal or a tracking error signal from versions of the digitized sensor signals; perturbing the digital servo system by adjusting either the focus error signal or the tracking error signal responsive to a perturbing signal to provide an adjusted error signal; obtaining a frequency response curve of the adjusted error signal within the digital servo system over a range of frequencies in response to the perturbation of the digital servo system; searching the frequency response curve for at least one frequency having a peak frequency response; and setting notch filter parameters of the notch filter to filter signals in the digital servo system at the at least one frequency.