| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance reliability by generating a servo control signal while averaging error information obtained based on a measured tracking detection period to stabilize a tracking servo and to improve an error rate. SOLUTION: A target speed signal CV from a subtractor 66 is increased or decreased arround a prescribed speed in accordance with a tracking error SV. At the time of reproducing, a tracking error is generated by comparing the measured value for a tracking detection period to be measured from timing detection pulses with the reference value stored on an A azimuth track. Moreover, a tracking error is generated by comparing the measured value for a tracking detection period to be measured from timing detection pulses with the reference value stored on an B azimuth track. Then, the tracking error SV as the servo control signal is generated by performing a servo gain processing and an averaging processing as to obtained two tracking error.</p> |
