Patent ID: 7791996
Filing Date: 2010-09-07
Classification: G11B

Abstract:
1. An optical disk device that records and/or reproduces information by irradiating an optical beam to an optical disk having a wobbled track, the optical disk device comprising: a wobbling detector adapted to detect a wobbling signal based on a reflection light of the irradiated optical beam; a delta-sigma modulator adapted to execute delta-sigma modulation to the detected wobbling signal based on a predetermined operation clock; a VCO (voltage controlled oscillator) of which an output oscillation frequency changes according to an input; a phase error detector adapted to detect a phase error between the delta-sigma modulated wobbling signal and a carrier signal output by the VCO, and output a phase error signal based on the detected phase error; and a loop filter adapted to execute a filter process to the phase error signal output by the phase error detector, wherein the VCO uses an output of the loop filter as an input signal, and wherein the phase error detector outputs the phase error signal by inverting positive and negative signs of an output of the delta-sigma modulator based on a signal acquired by ternarizing an output of the VCO by using positive and negative two thresholds.