Patent ID: 7209421

Claim:
An optical disk apparatus for recording or reproducing data on and from an optical disk, the apparatus comprising: a wobble of said optical disk being a sawtooth wobble which is obtained as a result of a sine wave being added to or subtracted from a cosine wave of predetermined frequency; light-receiving means for receiving a laser beam reflected from said optical disk; and wobble processing means for acquiring a wobble signal from a signal output from said light-receiving means, wherein said wobble processing means comprises differentiating means for differentiating a signal output from said light-receiving means; binarizing means for binarizing a differential signal from said differentiating means through use of a threshold value; pulse length detection means for detecting pulse lengths of two values of a binary signal from said binarizing means; and demodulation means for demodulating said binary signal in accordance with said pulse lengths of said respective two values of said binary signal.