| 摘要 |
PURPOSE: An adjusting method for focus bias in an optical disk player is provided to adjust focus bias in considering changed rate of jitter amount. CONSTITUTION: An optical disk is mounted on an optical disk player. A focus bias voltage F(A) for detecting a maximum positive jitter amount and a focus bias voltage F(B) for detecting a maximum negative jitter amount are stored in a store unit. Then, a focus bias adjust unit transfers a focus bias voltage F(A') adjusted from the focus bias voltage F(A) to an actuator coil of the optical disk player. The optical disk player reproduces an optical disk for supplying a reproduced signal to a jitter amount detect unit. Information about the jitter amount is stored in a memory. The focus bias adjust unit a maximum focus bias voltage F(B') to an optical pickup unit. The optical disk is reproduced for supplying a reproduced signal to the jitter amount detect unit. Then, a jitter amount is detected for supplying information about the jitter amount to the system control unit. A positive jitter amount change amount is calculated by subtracting F(A') from F(A), and a negative jitter amount change amount is calculated by subtracting F(B') from F(B). Then, the positive value is compared with the negative value.
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