| 摘要 |
PURPOSE:To shorten the pull-in time of the phase synchronization at starting time by forming a compensating circuit which receives an error signal of the first switch circuit for detecting the starting time and the second switch circuit for operating inversely to the first circuit. CONSTITUTION:The speed and the phase of a motor 1 for magnetic recorder/ reproducer are inputted to a mixer 7 to obtain a mixture error signal, thereby controlling the rotation of the motor 1 through a compensating circuit 8. The circuit 8 is formed of an arithmetic amplifier 10, a transistor T2 for detecting the starting time, and transistors T1, T3 operating inversely to the transistor T2. Accordingly, when the error signal becomes low level at the starting time, T2 becomes OFF to set the T1 to OFF and the T3 to ON, thereby charging a capacitor C by a DC voltage V2 equal to the ordinary voltage of the error signal, and the T1-T3 are inverted after starting, thereby accelerating the charging of the capacitor C and shortening the pull-in time. |
