METHOD AND DEVICE FOR DETECTING LAND/GROOVE CHANGE POSITION AND INFORMATION RECORDING/REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To stably switch the polarity by outputting a land/groove substitute change position detection signal independent of the quality of an optical disk in land/groove polarity switching control used for an optical disk recording/ reproducing device. SOLUTION: A time difference between a land/groove change position detection signal 17 and an origin signal 15 of a rotary encoder 16 is detected by a first counter 23, and further, the data equivalent to the time difference are held and preset to a second counter 26, and the counter end signal 30 of the second counter is made the land/groove substitute change position detection signal of the land/groove change position detection signal 17.