| 摘要 |
PURPOSE:To stably maintain the speed of a disk without influence of the magnitude of the inertial moment of the disk by detecting the timing change of a starting current, and automatically switching the set of the delay compensation time constant of a pulse for driving a motor. CONSTITUTION:The speed of a motor 2 which drives a digital audio disk 1 is detected by a detector 3, compared with a reference pulse 5, thereby controlling the motor 3 through a delay compensating circuit 7. The motor current is detected by a resistor 24, and a ON-OFF switch 17 of a capacitor 16 in the circuit 7 is controlled through a comparator 26 and a flip-flop 38, to which a start signal 31 is applied through a monostable multivibrator 30. Accordingly, the switch 17 is changed by the magnitude of the starting current of the motor 2 due to one- side performance or both-side performance of the disk 1, the set of the time constant of the delay compensating circuit is automatically varied to stably maintain the speed during the performance. |
