| 摘要 |
PROBLEM TO BE SOLVED: To surely detect the presence or absence of a wobble signal without being affected by noise etc. SOLUTION: The wobble signal detecting circuit of an optical disk reproducing apparatus for reproducing the optical disk including portions where guide tracks are made to meander at a specific period is equipped with a photodetector 31 of an optical pickup 3, a first filter circuit 36 and second filter circuit 37 which vary in passage areas and respectively extract the wobble frequency components of the portions made to meaner based on the output of the photodetector 31 and a system controller 10 which decides the presence or absence of the wobble signal by comparing the wobble frequency components extracted from each of two kinds of the filter circuits 36 and 37. The system controller 10 compares the frequencies of the wobble frequency components extracted by the two kinds of the filter circuits 36 and 37 and decides the presence of the wobble signal when the frequency ratio or the frequency difference is below the preset specified value. COPYRIGHT: (C)2005,JPO&NCIPI
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