Patent ID: 6834031
Filing Date: 2004-12-21
Classification: G11B

Abstract:
A disk drive unit, in which wobble components are sampled from laser beams reflected from an optical disk so as to write data on the optical disk, comprising:a first photo diode or detecting one longitudinal edge of a wobble groove of the optical disk; a second photo diode for detecting the other longitudinal edge of the wobble groove; a differential amplifier to which signals are sent from said first and second photo diodes receiving the reflected laser beams, said differential amplifier shaping a flexure caused by a difference of luminous power between low power laser beams of the reflected laser beams, which are used for reading data, and high power laser beams thereof, which are used for writing data, and sampling the wobble components only; a noise removing circuit for removing noise from the wobble components sampled by said differential amplifier; and a comparator digitizing the wobble components from which the noise has been removed by said noise removing circuit.