| 摘要 |
PURPOSE:To record a good black and white picture by providing a discrimination circuit and preventing an input luminance signal from passing through a comb-line filter in the case of the black and white picture. CONSTITUTION:When the luminance signal of the black and white picture is inputted to an input terminal A, the discrimination circuit 10 detects the absence of a color burst signal, discriminates that it is the black and white picture and controls the first switch circuit 8 and the second switch circuit 13. At this time, the second switch circuit 13 selects the luminance signal inputted to the input terminal A of the device and supplies to the input of the first FM modulator 4 to perform the FM modulation. This FM modulation signal is further inputted to the second addition circuit 9, however, the first switch 8 controlled by the discrimination circuit 10 operates so as to prevent the output signal of the second FM modulator 7 from being supplied to the second addition circuit 9.
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