| 摘要 |
PURPOSE:To reduce distortion trouble by taking out cross modulation components from a TV signal to a pilot signal through a filter which allows the above components to pass a horizontal scanning frequency of the TV signal and integer multiple of the above frequency and also lowering the amplification degree at levels. CONSTITUTION:Signals included by the TV signal and non-modulated pilot signal enter in an input terminal 1 and is amplified by a line amplifier 8. The pilot signal receiving cross modulation is extracted by the first filter 18 and is amplified by a pilot signal amplifier 19 then envelope lines can be taken out after being detected by a detector 20. An output of the detector 20 permits one or plural components among frequency components of the horizontal scanning frequency and integer multiple of the frequency to pass the second filter 9 then develops detecting signals. The second filter 9 allows S/N of the detecting signals to improve. The detected signals are amplified by a detection amplifier 10 and detected signal levels are detected by a level detector 11. If the detecting signal levels go to abnormally hi the distortion is lightened by lowering amplification degree of the line amplifier 8. |
