| 摘要 |
PURPOSE:To exactly detect trouble due to increment of distortion by feeding a non-modulated pilot signal to the input of a line amplifier and also taking out cross modulation components from a signal being transmitted to a pilot signal then monitoring their levels. CONSTITUTION:A transmitting signal is inputted in an input terminal 1 and a non-modulated pilot signal which is obtained by a pilot signal generator 25 is injected by a frequency collector 24 then is amplified by a line amplifier 8. The cross modulated pilot signal among output signals is extracted through the first filter 18 and is amplified through a pilot signal amplifier 19, then is applied with envelope detection by a detector 20 as an alternating current component, the second filter 9 passed only alternating current components and develops detecting signals. The detecting signals are amplified by a detecting signal amplifier 10 and are decided in level after allowing the detecting signals to pass through an appropriate time constant circuit by a decision device 12. If detected signal levels are decided to have gone abnormally high by the decision device 12, the decision device 12 will output a signal showing the generation of trouble due to increment of distortion at a decision output terminal 13. |
