| 摘要 |
A video titling device for color television pictures wherein the color transmission system is of the SECAM, NTSC or PAL types in which the luninance signal and chrominance signal making up the composite video signal are separate signals. A part of the luminance signal spectrum Y is extracted from the input video signal having a chrominance subcarrier S.P. carried through a single filtering step without modifying the composite input signal. Thus from the composite input video signal of luminance signal Y and chrominance signal S.P. (Y + S.P.) through a single filter, the subtraction of the amplitude of a direct predetermined luminance signal K from the amplitude of luminance signal Y provides a (Y-K) signal. This Y-K signal is then cut out by switching means at a reference voltage under the control of a switching signal representing those selected pictures for the titling operation, and the aforesaid cut out signal is then subtracted from the input video signal (Y + S.P.). Whenever the switching signal selects the reference voltage, the output video signal is identical to the input video signal (Y + S.P.). Whenever the switching signal selects signal (Y-K), the output video signal transmits the special effects pictures with a predetermined luminance K and a chrominance equal to that corresponding to the composite input video signal.
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