| 摘要 |
PURPOSE:To prevent the misreception when the data signal is transmitted in piling onto the aural signal, by deciding the incoming break of the data signal when the aural signal is detected out of the signals to be received and then deciding only the data signal received when no aural signal exists as the correct data. CONSTITUTION:The aural signal sent from input terminal 1 is supplied to transmission device 2, and the data signal is supplied from input terminal 3 via band pass filter 4. And the output of device 2 is supplied to reception device 6 via transmission line 5. The output detected through device 6 is led out to output terminal 7 in the form of the aural signal and also supplied to band pass filter 8 and low pass filter 11. When the signal higher than the prescribed level is detected at detecting circuit 12 and through filter 11 in case the aural signal exists, gate circuit 3 is closed to block the passage of the data signal. While gate circuit 13 is opened in case no aural signal exists to lead out the given data signal through output terminal 10 via filter 8 and detecting circuit 9 each. |
