Abstract: Circuitry implementing at least two amplitude level detectors and a method for monitoring their ability to track rapid changes in signal level is shown. The monitoring circuit uses a delay network to provide an indication that the detectors have not been driven into conduction during a specific interval of time. If this operation persists, a resetting circuit discharges the detector output filter network, thereby allowing the detectors to re-establish an output indicative of the present input signal level. A commutating circuit is shown which allows a single delay network to be used in conjunction with at least two level detectors.

Abstract: Cathode ray tube adjusting apparatus in a color television receiver includes a matrix and amplifier circuit coupled to a chrominance signal source, selectively coupled by a "service-normal" switch to a luminance or reference signal source. The matrixing and amplifying circuit includes a control grid DC bias potential development circuit and a cathode DC bias potential adjusting circuit, and is coupled to a cathode ray tube. In the "service" switching position, the DC bias potential adjusting circuit is varied to provide the proper cut-off potential conditions for the cathode ray tube. In the "normal" switchingposition, chrominance and luminance signals are matrixed and luminance signal drive is adjusted to provide the proper color temperature appearing on a viewing screen of the cathode ray tube.