| 摘要 |
<p>PURPOSE:To perform variable speed reproduction by detecting the amplitude variation of a difference frequency component obtained by converting the frequency of a reproduced pilot signal by a pilot signal generated in an opposite time-series order to that during recording, and making the frequency of a detection signal constant. CONSTITUTION:Pilot signals P0 and P1 during variable speed reproduction and standard reproduction are frequency-converted by a circuit 31; when their difference frequency component is f3-f4=fH or f1-f2=fH, the frequency of the output J of a frequency dividing circuit 42 when the output E of a detecting circuit 32 is maximum is equal to that of a pulse S, and the output J is phase-compared with a reference signal from a circuit 10 by a circuit 43, which outputs an error signal to a circuit 36. The output H of a shaping circuit 40 is supplied to a frequency discriminating circuit 38 to output an error signal. This signal and the error signal from the circuit 43 are summed up by the circuit 36, whose output is supplied to a motor 5. Consequently, the motor 5 is controlled so that the frequency fn of the output G is constant and the output J is in phase with the reference signal. Therefore, the pulse S and output G are combined together synchronously to perform the variable speed reproduction.</p> |
