| 摘要 |
PURPOSE:To prevent the generation of malfunctions by separating the video intermediate frequency output from the sound intermediate frequency output and at the same time using a terminal exclusive for sound intermediate frequency output. CONSTITUTION:A tuner 1 mixes a high frequency signal S3 and a local oscillation signal S4 delivered from a local oscillation circuit and also separates the sound intermediate frequency from the video intermediate frequency to deliver them to terminals 2 and 3. The signal delivered through the terminal 3 has improved out-band characteristics since the video intermediate frequency (point P) and a color intermediate subcarrier wave (point C) are lower than the peak by about 1-3dB. Thus the gains of the sound intermediate frequencies S1 and S2 are reduced satisfactorily in order to reduce the sound beat disturbance. The sound intermediate frequency signal delivered through the terminal 2 has wide and approximately flat characteristics. Thus the frequencies (point P, S1 and S2) are kept lower than the peak by about 0.5-2dB. This prevents the mutual modulation between a video signal and a color subcarrier wave.
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