| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique to detect the eccentricity, wobbling and eccentric centroid of an optical disk in an optical disk unit. SOLUTION: Detections of the amount of eccentricity, wobbling and eccentric centroid are conducted in parallel while their operating time zones are mutually superimposed. Detections of eccentricity and eccentric centroid are conducted by counting the number of pulses of tracking error signals. Wobbling detection is conducted by detecting the level of focus drive signals. Detections of eccentric centroids, in particular, are conducted in a plurality of speed regions while the number of revolutions of the optical disk is increased, when the amount of the eccentricity and the amount of wobbling are within prescribed values. COPYRIGHT: (C)2005,JPO&NCIPI
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