Abstract: In a television receiver, a horizontal peaking signal is formed for addition to a luminance signal to enhance its horizontal detail by relatively boosting high frequency components of the luminance signal. The peaking signal is subject to a coring action with the depth of coring subject to dynamic control in accordance with level variations of low frequency content of the luminance signals. The sense of control is such that a greater coring depth is associated with dark portions of a scene to be reproduced than is associated with bright portions thereof.

Abstract: A color television receiver includes apparatus for automatically controlling the high frequency peaking content of the luminance signal component of a color television signal. The luminance signal is controlled to exhibit significant depeaking in the presence of weak, noisy received color television signals, and, simultaneously, the magnitude of the chrominance signal component of the television signal is reduced to prevent a displayed color picture from appearing to exhibit oversaturated color.

Abstract: A service switch in a color television receiver for simulating quiescent signal conditions to permit set-up adjustment of a color image reproducing kinescope responsive to luminance and chrominance signals processed by luminance and chrominance channels of the receiver. Separate, adjustable image brightness and contrast control networks are coupled to the luminance channel for respectively varying a D.C. level and peak-to-peak amplitude of the luminance signal. The switch has "normal" and "service" positions and is coupled to the chrominance channel, brightness and contrast networks, and a vertical deflection circuit of the receiver. In the "service" position, the switch renders the chrominance channel inoperative to process the chrominance signal, and disables vertical scanning of the kinescope. The switch also causes the brightness and contrast networks to establish predetermined values of the D.C.