| 摘要 |
PURPOSE:To perform accurate tracking control even when a disk is inclined, by detecting the inclination of the recording medium from the value of a track signal obtained when a discontinued section formed in a part of a guide groove and correcting the error resulting from the inclination of the track signal. CONSTITUTION:A reformat sectin is installed to a part of a guide groove and a reformat signal at the time of irradiation is detected by means of a halved photoreceptor element 8. Outputs of elements C and D become a track signal (d) after passing through a subtractor 17 and a signal (f) indicating the inclination of a disk is obtained by sampling the signal on the convex surface of a preformat section only by means of a sample and hold circuit 23. The signals (d) and (f) are passed through amplifiers 20 and 21 with amplification gains alpha and beta (set at A/B=alpha/beta against the deviated quantities A and B of the track signal (d) caused by the inclination) and a signal (g) which is obtained by subtracting A from the signal (d) and multiplying the (d-A) by beta is outputted. The signal (g) becomes a tracking controlling signal (h) after passing through a phase compensating circuit 18. Therefore, accurate tracking control can be performed even when a disk is inclined. |
