| 摘要 |
<p>PURPOSE:To perform the assured program searching, by charging a capacitor after giving the wave detection to the output of a tape under a high-speed reproduction mode, actuating a Schmitt trigger circuit with the obtained voltage to actuate an FF and then to drive a plunger and then switching the operation to a constant speed mode. CONSTITUTION:A capacitor C is charged after giving the high pass saturated amplification 21 and the wave detection 22 to the output of a tape under a high- speed reproduction mode. This output of the tape is fed to a Schmitt trigger circuit 24 as well as to a comparator 26. An FF24 is preset at the signal existing part of the tape and delivers level 1 through a terminal Q. When the signal voltage V2 drops at the non-signal part of the tape, the output of the circuit 24 is set at 0 and then inverted 27. Thus an AND circuit 28 delivers an output to drive a plunger driver 29. Thus a plunger PL is actuated to switch the operation to the constant speed mode. At the same time, the comparator 26 compares the voltage V2 with the reference voltage VR and feeds the clear signal CL to the FF. Thus a silent part is detected accurately at an interval of music, and the program searching is possible in an assured way.</p> |
