| 摘要 |
PURPOSE:To allow a detecting circuit for broadcast signals of an emergency warning, etc., to detect a start signal securely and also to have a buffer time of transition to release reception by inhibiting the acceptance of an end signal for a certain time after the start signal is detected. CONSTITUTION:When six pulses for indicating the starting of a broadcast are applied to an input terminal 21, the signal is applied to a terminal 28-S of a reception driving circuit 28 through an initial value setting circuit 22, a start detecting ciruit 23, and NAND circuits 26 and 27 to hold the reception of a broadcast of an emergency warning, etc., in readiness, and also to turn on a start display diode 29. The signal from an output terminal 28-Q of the circuit 28 is applied to a control circuit 30 to inhibit the application of the signal appearing at the input terminal 21 to an end detecting circuit 24 for 12 seconds. Three broadcast end pulses generated later are applied to an end driving circuit 37 through the end detecting circuit 24, a timer circuit 33, and an NAND circuit 35 to end the reception, and also to turn on an end display diode 38. |
