| 摘要 |
PURPOSE:To automatically adjust the closed loop gain quantity in a closed loop servo-mechanism for positioning a head by providing the closed loop servo- mechanism for positioning the head, and an automatic loop gain adjusting means which can adjust automatically the open loop gain quantity of this closed loop servo-mechanism. CONSTITUTION:A switch 11 is set to a turn-on state, and subsequently, the open loop gain quantity of a head positioning control circuit at the present time point is detected. Next, a microprocessor 15 compares the open loop gain quantity of the present time point and a target value, and executes a gain correction of a loop gain adjusting circuit 12 by outputting a control instruction in accordance with necessity. By repeating them, an optimal open loop gain quantity satisfiable of the target value is obtained finally. Thereafter, by setting the switch 11 to a turn-off state, a regular head positioning control state can be set. In such a way, the open loop gain quantity in a closed loop servo-mechanism being the head positioning control circuit can be adjusted automatically, and high reliability can be obtained. |
