| 摘要 |
PURPOSE:To attain most video signals to be recorded without any modification by recording a video signal and an audio signal simultaneously after a level of a prescribed frequency part including a frequency common band of the video signal so as to facilitate to make a luminance signal used in a broad band. CONSTITUTION:A video signal being the result of common band multiplex to a chrominance carrier signal obtained by applying orthogonal biphase modulation to a chrominance subcarrier of 2.56MHz by means of two kinds of color difference signals and a luminance signal subject to broad band processing by the frequency interleaving method is supplied to an input terminal 1. The signal is supplied to a noise attenuation filter 2 and an LPF 3. The luminance signal level giving an adverse effect as a noise to a sound FM signal with the noise attenuation filter 2 is attenuated by the filter 2. Then a noise reduction filter 2 attenuates a luminance signal level giving adverse effect as noise onto an audio FM signal. Only the luminance signal subject to broad band processing is obtained by an LPF 3. The video signal passing through the filter 2 and the LPF 3 is inputted to a variable attenuation circuit 4, where the radio of summation is changed and the result is amplified by amplifiers 5, 6. Moreover, a BPF 7 passes through the audio frequency band giving adverse effect onto the audio FM signal in the video signal, the signal of the said frequency band is smoothed (8) and fed to a slider of the circuit 4 as a control signal, and the result is added (9) in the output of the amplifiers 5, 6 as the output.
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