| 摘要 |
PURPOSE:To maintain the various characteristics of a system at the controlling time constant by varying the gain of speed controlling means in response to the output of traverse position detecting means, thereby always maintaining the gain of a linear speed control loop. CONSTITUTION:Recorded information of a disc 1 on which voice or picture information is recorded is detected by pickup means 2, and clock signal is extracted by a clock extracting circuit 3 from the detected information. A phase control loop is composed of the disc 1, pickup means 2, clock extracting circuit 3, phase comparator 6, high band compensator 7, power amplifier 8 and motor 5, and the motor 5 is rotatably controlled so that the extracted clock frequency becomes equal to a reference frequency. The gain of the speed control circuit 4 is controlled by the output of a traverse position detector 10 which outputs a voltage corresponding to the traverse position of the means 2. |
