| 摘要 |
PURPOSE:To lock in quickly and stably the tracking servo by driving a fine control means in response to the drive signal of a rough control means in a drive mode of this rough control means and therefore attaining the accurate reproduction of the signals sent from a pickup even in an access mode. CONSTITUTION:A disk 1 is revolved by a motor 2 via a control circuit 12, and a control circuit 11 performs the focus and tracking servo operations. A microcomputer 10 delivers an access command for execution of a basic action. In this case, a tracking servo loop is opened and a radius position detecting circuit 6 detects the distance to an access target. Then the target shift speed of a carriage corresponding to said detected distance is delivered from a target speed generating circuit 7. The difference between a target speed and the actual speed of a pickup 3 detected by a relative speed detecting circuit 5 to the disk 1 is obtained through an amplifier 8. Then a linear motor 4 is driven in accordance with the difference signal obtained from the amplifier 8. Thus the servo is applied. A drive current of the motor 4 is detected 13 and multiplied 14 by a prescribed coefficient for fine control of a beam spot. |
