Optical disk drive and methods for counting the number of tracks on an optical disk

摘要

The invention is a positive peak level comparator for generating a positive peak pulse when a TES (Tracking Error Signal) is higher than a predetermined positive level, a negative peak level comparator for generating a negative peak pulse when the TES is lower than a predetermined negative level, and a logic circuit for generating an output pulse when said positive peak pulse and said negative peak pulse have been alternately input thereto. The arrangement prevents the TES from being miscounted even if the TES is distrubed due to the occurrence of, for example, a noise at a level close to either said predetermined positive level or said predetermined negative level and either said peak pulse or said negative pulse is successively generated.