| 摘要 |
PROBLEM TO BE SOLVED: To quickly and precisely detect a tilt of an optical disk with respect to a reference surface. SOLUTION: When a tangential tilt increases to a minus side, a filter f1 generates a signal containing a signal component increasing as the tangential tilt increases, and when the tangential tilt increases to a plus side, a filter f2 generates a signal containing a signal component increasing as the tangential tilt increases. Then a jitter value acquiring circuit 109 acquires a jitter value from the output signal of the filter f1 and a jitter value acquiring circuit 119 acquires a jitter value from the output signal of the filter f2. Then a subtracter 121 calculates the difference between output signals of the respective jitter value acquiring circuits and generates a tangential tilt signal. COPYRIGHT: (C)2007,JPO&INPIT
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