| 摘要 |
<p>PURPOSE:To reduce a disturbance by a detecting signal by switching a recording time of a program searching detecting signal, by interlocking with switching of a running speed of a magnetic tape of a recording time so that the length of a recorded program searching detecting signal becomes almost constant. CONSTITUTION:When a control device 4 is in other than a sound recording mode, an output of a terminal R becomes L, and an input of an AND circuit 13 becomes H and L, therefore, its output becomes L, an AND gate 5 is closed, and a program searching detecting signal is not supplied to a head 1. When the control device 4 is switched to a sound recording mode, its output becomes H, an output of an invertor 14 becomes L, and the potential of a capacity 8 is discharged through a resistance 7 and becomes L gradually. Before the potential of the capacity 8 becomes below a threshold level of the AND circuit 13, its output becomes H, and the program searching detecting signal is recorded. When a tape speed is switched to a low speed, a switch 12 is turned on, therefore, a transistor 10 is turned on, the capacity 8 and 9 are connected in parallel, and a drop of the input potential of the AND circuit 13 becomes slow. Therefore, by setting the length of the program searching detecting signal to the same extent as the high speed time, a disturbance by a detecting signal is reduced.</p> |
