Patent ID: 6813228
Filing Date: 2004-11-02
Classification: G11B

Abstract:
A method of sensing direction of motion of an optical pick-up unit moving laterally over an optical medium in optical disk drive, comprising:receiving optical signals from at least one detector in the optical pick-up unit; forming a direction sum signal from the optical signals from the at least one detector; forming a tracking error signal from the optical signal from the first side element and the optical signal from the second side element; filtering the direction sum signal with a first high-pass filter to form a filtered sum signal; filtering the tracking error signal with a second high-pass filter to form a filtered tracking error signal; indicating a first direction if the filtered sum signal and the filtered tracking error signal are of opposite sign; and indicating a second direction, the second direction opposite the first direction, if the filtered sum signal and the filtered tracking error signal are of the same sign.