| 摘要 |
PURPOSE:To minimize the error between the number of tracks to be shifted and the number of tracks which shifts actually by cutting off a tracking servo-loop prior to access, and by releasing the interception of the servo when the number of detections of N numbers of rotation pulses per rotation becomes N integer multiples. CONSTITUTION:When a tracking servo-loop is cut off prior to access and the random access indication is executed, the number of tracks to be shifted is calculated from the present location address and the destination address of pickup. The N number of rotation pulses per rotation is calculated from the point when the servo is cut off, and when the counting becomes N integer multiples, the servo is released. At this time, the present location address is read, and it is compared with the destination address. In addition, the above-mentioned processing is repeated when the track shift is necessary, and the normal playing condition begins by completing the access when the track shift is not necessary. Therefore, the error between the number of tracks to be shifted and the number of tracks which shift actually is minimized. |
