Patent ID: 6992962
Filing Date: 2006-01-31
Classification: G11B

Abstract:
1. A wobble signal detection circuit for an optical disk apparatus which detects a wobble signal by focusing a light beam into a spot on a pregroove on an optical disk during recording of data onto and reproduction of data from the optical disk, and includes a photodetector which detects first and second lights from first and second portions of the spot, respectively, and outputs first and second detection signals corresponding to respective power levels of the first and second lights, the first and second portions being formed by splitting the spot into two portions in parallel with a scanning direction, said wobble signal detection circuit comprising: a sample-and-hold circuit sampling and holding the first and second detection signals output from said photodetector during the recording of the data onto the optical disk; lowpass filter means for reducing noise components of the respective first and second detection signals, the noise components being generated by sampling the respective first and second detection signals in said sample-and-hold circuit; and subtraction means for calculating a difference between the first and second detection signals respectively output from said lowpass filter means so as to obtain the wobble signal.