VIR Control of hue and saturation in RGB demodulator

Claim 1

A chrominance signal controlling apparatus for controlling the chrominance signal in a color television receiver employing a primary color signal demodulator providing only red, green and blue primary color signals at the output terminals thereof, said apparatus comprising: a luminance signal producing means for forming a luminance signal by mixing said red, green and blue primary color signals in substantially the ratio A.sub.R sin(θ.sub.R -θ.sub.G)sin(θ.sub.R -θ.sub.B): A.sub.G sin(θ.sub.G -θ.sub.B)sin(θ.sub.G -θ.sub.R):A.sub.B sin(θ.sub.B -θ.sub.R)sin(θ.sub.B -θ.sub.G) respectively, where A R , A G and A B are the respective red, green and blue relative demodulation gains of the primary color signal demodulator and θ R , θ G and θ B are the respective red, green and blue demodulation angles of the primary color signal demodulator; a subtracting means connected to said luminance signal producing means for producing a difference signal between one of the primary color signals and said luminance signal; and a comparing means connected to said subtracting means for comparing the level of said difference signal with a predetermined reference level for producing a control signal for controlling the chrominance signal level and/or the phase of a carrier wave by keeping the level of said difference signal equal to said reference level.