| 摘要 |
PURPOSE:To exactly control an arm at a low cost, by modulating pulse width of a signal which has detected relative deviation between a picture signal fetching part and a pickup arm, comparing it with the reference potential, and driving a DC motor by a deviation pulse. CONSTITUTION:A detecting signal derived from a stylus deviation detector 1 is amplified by an amplifier 2. By an absolute value circuit 9, the detecting signal derived from the amplifier 2, and a polarity signal derived from a polarity circuit 11 are led in, and detecting voltage in the reference position of a stylus against a pickup arm is set as reference voltage, by which an absolute value signal related to a relative position of the stylus is obtained. This absolute value signal is applied to a pulse width modulating circuit 10, by which it is possible to obtain a driving pulse of the motor having pulse width which is varied by the relative position of the stylus against the pickup arm. |
