Abstract: There is disclosed a simplified bias and gain adjust system for a color cathode ray tube wherein, by a minimum of adjustments, the bias for an in-line color cathode ray tube may be adjusted to achieve color balance between the CRT's three electron guns and to achieve a maximum voltage difference between the CRT's G.sub.2 electrode and the cathode element of the dominant electron gun of the color CRT. In particular, the system includes a chrominance matrix amplifier including an amplifying element in the form of a transistor for each of the color-difference signals provided by the chrominance demodulator(s) of the color television system; the color-difference signal is applied, illustratively, to the base of each such transistor, and a luminance signal Y is applied to the emitter of each such transistor element.

Abstract: There is disclosed an AFT summing circuit for a varactor-type tuning system and in particular for such a tuning system including a UHF tuner and a VHF tuner. A tuning voltage derived from a suitable source indicative of the desired channel or station to be tuned is applied to one input of the AFT summing circuit, while an error signal as derived from an AFT circuit is applied to the other input, to be summed together in a manner whereby the effect of the AFT signal may be adjusted without affecting the tuning voltage. The AFT circuit output is applied at a first level when the VHF tuner is operative, and at a second attenuated level when the UHF tuner is operative. In particular, the AFT summing circuit includes first and second impedance elements for applying the AFT circuit output to first and second input terminals of an operational amplifier, and a third impedance element for applying the tuning voltage to the second input terminal.

Abstract: A single, combined contrast/brightness control is disclosed herein for a television receiver. A contrast control in the form of a variable potentiometer, is coupled to the output, driver transistor of the video amplifier, which serves to amplify and apply the video signal to the cathode ray tube (CRT) and including AC/DC coupling in the form of a resistor and a capacitor. The DC coupling resistor sets the DC bias level to the output transistor and in particular to its base at a level dependent upon the DC level established across the constrast/brightness control potentiometer. Further, the AC coupling capacitor is selectively charged to further adjust the DC bias of the output transistor to a level with the DC coupling resistor whereby the black level of the output signal applied to the cathode ray tube is maintained relatively constant with regard to a predetermined level.

Abstract: An automatic hue control circuit is disclosed for a color television receiver, wherein the flesh-tone signals of the reproduced image are enhanced by spreading the phase angle between the R-Y and the B-Y reference signals before applying them to their respective demodulators. In one aspect of the invention, the flesh-tone enhancement by phase-shifting the R-Y and B-Y signals occurs only for positive values of the flesh-tone signals. In a further aspect of this invention, a simplified automatic hue control circuit is disclosed as comprising a matrix for receiving, respectively, the R-Y, the G-Y and the B-Y color signals to obtain a DC quiescent voltage with which the flesh-tone signal, as indicated by the sum of the R-Y and the G-Y signals, is compared to render conductive a switch, illustratively in the form of a diode, whereby the phase-shift is imparted to the R-Y and B-Y reference signals.