Luminance/chromaticity signal separation circuit for composite video signal

DETAILED DESCRIPTION It is an object of the present invention to provide a luminance/chromaticity signal separation circuit for a composite video signal capable of exactly separating the luminance signal and the chromaticity signal even when a small variation of vertical luminance signal is present.
It is another object of the present invention to provide a luminance/chromaticity signal separation circuit for a composite video signal capable of exactly performing the separation of the luminance signal and the chromaticity signal with much simpler structures by using only two one-line delayers.
Such objects of the present invention can be attained by setting up three line comb filters which are adapted to respond to vertical luminance variations using two one-line delayers, comparing a line signal at present with preceding and following adjacent line signals, selecting an output signal from the line comb filter which has a smaller luminance difference when the luminance difference is above a certain level for the separation of the luminance signal and the chromaticity signal, and selecting an output signal from the line comb filter which uses all of the two one-line delayers when said luminance difference is below a certain level.