Modulated fleshtone and tint correction circuitry
AssigneeGTE Sylvania Incorporated
InventorRobert Charles Wheeler
Life of this patent
Estimating the term…
Abstract
A fleshtone and tint correction detector DC coupled to at least two of the first, second, and third demodulator stages of a color television receiver provides a control signal in response to a shift in differential potential output from the demodulator stages to effect a shift in phase angle of reference signals applied in the demodulators whereby fleshtone and other color errors are reduced with a minimum deleterious effect on other colors.
Claims16
A fleshtone and tint correction circuit for a color television receiver having chrominance and reference oscillator signal sources comprising:
- first, second, and third color demodulator stages coupled to said chrominance and reference oscillator signal sources;
- phase angle modulator means coupled to said reference oscillator signal source for altering the phase angle of signals applied to at least two of said first, second, and third color demodulator stages;
- and
- fleshtone and tint correction detector means DC coupled to said first, second, and third color demodulator stages and to said phase angle modulator means, said detector means responding to the output from said demodulator stages to provide a control signal for altering the phase angle between at least two of said reference oscillator signals applied to said demodulator stages.
In a color television receiver having a reference oscillator and chrominance signal sources, a fleshtone and tint correction circuit comprising:
- first, second, and third sources of color demodulator signals coupled to said reference oscillator and chrominance signal sources;
- fleshtone and tint correction detector circuit means comprising a transistor DC coupled to at least two of said first, second, and third sources of color demodulator signals for effecting development of a control signal in response to a shift in differential output from said sources of demodulator signals;
- and
- phase angle modulator means coupled to said fleshtone and tint correction detector means and to said reference oscillator signal source, said modulator means responsive to said control signal from said fleshtone and tint correction detector means for altering the phase angle between two of the signals applied to said sources of demodulator signals from said reference oscillator signal source.
In a color television receiver having reference oscillator and chrominance signal sources, a fleshtone and tint correction circuit comprising:
- first, second, and third sources of color demodulator signals coupled to said reference oscillator and chrominance signals sources;
- fleshtone and tint correction detector means comprising an electron device having a first electrode DC coupled by first and second impedance to first and second sources of demodulator signals and a second electrode DC coupled to a third source of demodulator signals for effecting development of a control signal in response to a shift in differential output from said sources of demodulator signals;
- and
- phase angle modulator means coupled to said fleshtone and tint correction detector means and to said reference oscillator signal source to provide, in response to said control signal, alteration of the phase angle between two of the signals applied to said first and second sources of demodulator signals from said reference oscillator signal source when a color signal is in the first or portions of the second and fourth quadrants of a standard chrominance vector diagram.
Dependencies are inferred from the claim text.