PURPOSE:To improve the characteristic without requiring much cost by inserting a filter or a narrow band amplifier most suitable for the detection prior to a sound detector in a television receiver. CONSTITUTION:A band pass filter 10 having a characteristic where the video carrier versus sound carrier ratio of an input IF signal is decreased and the large attenuation is attained between both the carrier bands is inserted, between the sound 1st detector 9 and an IF amplifier 2. Then, the level of the sound carrier entering the sound 1st detector 9 is increased and the level of the video signal band is decreasd, the 4.5MHz component of the sound 1st detector output is increased and a high frequency of the video component due to the nonlinearity of the detector is hardly invaded in the 4.5MHz band, allowing to improve the S/N ratio.
展开▼
