| 摘要 |
PROBLEM TO BE SOLVED: To prevent instability of tracking control due to deviation of balance of a tracking error signal caused by movement of a field of vision of an object lens. SOLUTION: Tracking support control is performed by a hysteresis tracking error signal Teh generated by masking a signal of a half period of an off-track of a tracking error signal. A transistor 146 is turned off by an inverse ENABLE signal indicating a time immediately after thread high speed feed for a tracking error signal TPP (TE) calculated by a tracking error calculation circuit 60, when a validated mirror signal MIRR is a high level indicating detrack, a transistor 144 is turned on, a hysteresis tracking error signal Teh reducing the tracking error signal to a ground level is generated, and tracking servo control is performed. Any component of the tracking error signal is reduced to a half, and oscillation of tracking servo control can be prevented. |
