| 摘要 |
PURPOSE:To detect an abnormal operation and to avoid the breakdown of a transmission tube, by extracting a part of the output signal of the transmission tube and discontinuing the working of the transmission tube when the undesired signal caused by the abnormal oscillation, etc. exceeds the comparison reference level. CONSTITUTION:The output of a transmission tube 1 is delivered via a directional coupler 5 and a transmission/reception switch 4. The signal extracted by the coupler 5 is fed to a filter 6 which transmits only the undesired frequency component and then converted into a video signal through a wave detector 7. The output signal of the detector 7 is compared with the comparison reference level through a comparator 8. A deciding circuit 9 decides whether the transmitting operating should be discontinued or not. This decision cuts the supply of a trigger signal to a modulator 2 by a gate circuit 10. Thus the working is discontinued for a transmitting device. |
