| 摘要 |
PURPOSE:To monitor cross modulation distortion, generated in a repeater, all the time by partially extracting a television received wave and a television transmitted wave by a coupler, and detecting and then comparing both of them. CONSTITUTION:A television repeated signal inputted from an antenna 1 is passed through a feeder 3, and repeated and amplified by a television broadcast repeater 4 to be outputted from an antenna 2 through the feeder 3. A received and a transmitted signal branched by a coupler are detected by video detectors 9 and 10, passed through low-pass filters 11 and 12, and then compared mutually by a differential amplifier 19. The output of the video detector 9 and that of the differential amplifier 19 are inputted to a comparing circuit 23 through band-pass filters 16 and 20, amplifiers 17 and 21, and detectors 18 and 22, and a cross modulation distortion component is outputted from the comparing circuit 23. |
