| 摘要 |
PURPOSE:To ensure a stable servo control during the reproduction by providing a circuit on a PCM type recording reproducer to automatically turn a switch circuit to the recording position when no frame synchronization signal is detected during the reproduction of record. CONSTITUTION:In operation of a PCM type recording reproducer, a signal of a frame synchronization detection circuit 37 is applied to a flip flop 44 through a one shot circuit 38 and the output thereof turns on a transistor 34 to change a contact 35a of a relay 35 over to the P position thereby controlling a motor 22. When no synchronization signal is generated, pulses with a respective width are outputted from second and third one-shot circuits 39 and 40. Only during the period, a relay contact 35a is turned to the servo position R during the recording with the output of the flip flop 44 at a level L. Therefore, the reproduction servo control is operated only when the frame synchronization signal is stable, thereby enabling a stable control. |
