| 摘要 |
An optical disc apparatus comprises, an optical pickup, a signal extracting unit for reading address information and an RF signal from an optical disc based on signal read by the optical pickup, and a main controller for performing jitter control and focus control. At an initial reading of the optical disc, the main controller determines whether an address information detector succeeds in reading the address information. If not successful (NO in S3), the main controller offsets a defocus position to two points in plus and minus directions from a defocus position giving best jitter (S7), calculates an approximate curve of signal level characteristics with a peak value (S8), and adjusts and allows the defocus value to correspond to this peak value (S9). If the optical disc apparatus cannot read address information, depending on the defocus value, it increases the signal level of the address information by the defocus position adjustment.
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