| 摘要 |
<p>PURPOSE:To decrease pull-in time of APC at starting of a motor by inserting a heat-sensing element in a limiter circuit, changing the upper and lower limit level at an ambient temperature, and making the APC locking state less out of place to release at a high and a low temperature. CONSTITUTION:An APC output signal in response to a phase of a capstan PG signal is introduced from a phase comparator 5, and the impedance conversion is applied through an integrating circuit 7, and the limiter circuit 14 is inserted between the integrating circuit 7 and an impedance converter 8. An APC output voltage across a capacitor C1 is changed by temperature as shown in (a), then the number of heat-sensing diodes and values of resistors R6, R8 are selected to change the voltage characteristics of points B, C in the limiter circuit 14 as shown in (b), (c), allowing to change the lower and the upper limit of the limiter circuit in matching with the fluctuation of the ambient temperature.</p> |
