Apparatus for and method of counting the number of tracks on an optical disk.

摘要

Optical disk drive apparatus comprises an optical head for projecting a laser beam onto the recording surface of an optical disk seek control means (90) controllers movement of the beam from a current track on the disk to a target track. Tracking error signal generating means (72) generates a tracking error signal (TES). The TES indicates the deviation of the beam from the centre of a track in the radial direction of the disk. Track number countering means counts, as a function of the TES, the number of tracks crossed by the optical head. The track number counting means comprises a positive peak level comparator (401) for generating a positive peak pulse when the TES is higher than a predetermined positive level; a negative peak level comparator (402) for generating a negative peak pulse when the TES is lower than a predetermined negative level; and a logive circuit (500) for generating an output pulse in response to the positive peak pulse and the negative peak pulse being generated in a predetermined sequence. This advantageously ensures that the number of tracks crossed is precisely counted even if the optical head passes over a defective portion of the disk. <IMAGE>