| 摘要 |
PURPOSE:To set an optical head at a specified address origin by temporarily moving the optical head to a limiter when a power source is turned on, and then moving the optical head in the opposite direction until the address origin is detected. CONSTITUTION:When a power source is turned on, an FF circuit 23 turns on a switch 27. A constant voltage source 29, a differential amplifier 31, and a motor driver 33 drive a motor 4 in a direction (a). The detection signal of a position detector 9 is differential to control the speed of a motor 9. A limiter 15 when struck outputs the detection signal to turn off the switch 27 through the FF circuit 23. The output of the limiter 15 also turns on a switch 23 to drive the motor 4 in a direction (b) through a constant voltage source 30 and the differential amplifier 31. At an address origin, the output of a mark detector 10 turns off a switch 28 through an AND circuit 25 and an FF circuit 26 to stop the motor 9 at the address origin. |
