Patent ID: 8737182
Filing Date: 2014-05-27
Classification: G11B

Abstract:
1. A method for operating a disc drive system, the method comprising: based at least in part on a first injector signal, oscillating a focusing apparatus of the disc drive system; while oscillating the focusing apparatus of the disc drive system and rotating a disc placed within the disc drive system, estimating an amplitude of a track crossing speed signal; generating a second injector signal having a frequency that is substantially the same as a frequency of the first injector signal; based at least in part on the estimated amplitude of the track crossing speed signal and the second injector signal, estimating a sign of the track crossing speed signal, wherein the track crossing speed signal comprises a low frequency component that is substantially due to the eccentricity of the disc and a high frequency component that is substantially due to the oscillation of the focusing apparatus; filtering the track crossing speed signal using a band pass filter such that an output of the band pass filter substantially comprises the high frequency component of the track crossing speed signal; multiplying the output of the band pass filter with the second injector signal to generate a multiplication signal; and filtering the multiplication signal using a low pass filter to generate a sign detection signal, wherein the sign detection signal provides an indication of the sign of the track crossing speed signal.