| 摘要 |
<p>PURPOSE:To provide a pause detector, which is so stable as is not influenced by the fluctuations in the main voltage, by connecting two sets of charge and discharge circuit in opposite directions between the base and emitter of a switching transistor. CONSTITUTION:In response to the reproduction of records in a tape 1 running at a high speed, the capacitors C1 and C2 of charge and discharge circuits, which are connected in opposite directions between the base and emitter of a switching transistor Q1' and which have larger and smaller time constants, are charged at the same rate through a limitter amplifier 4. As a result, even if the main voltage is varied to fluctuate the output of the amplifier 4, the transistor Q1, receives no influence therefrom. Thus, upon detection of the band of no signal of a pause between musics, the transistor Q1' is rendered conductive a preset time after the start of the detection of the no signal band in accordance with the difference in the discharge constances between the capacitors C1 and C2 so that the tape 1 restores its play speed by the action of the plunger which is energized through transistors Q2' and Q3'. Thus, it is possible to stably detect the pause without any influence from the fluctuation in the main voltage.</p> |
