Contrast/brightness control circuit for television receiver

摘要

The invention is subjected for a television receiver which is capable of simultaneously displaying a picture signal by at least first and second picture images on a cathode ray tube and including means for generating the first and second picture signal, a superimposer for selectively supplying the first and second picture signal to the cathode ray tube, an APL detector for receiving the first and second picture signals to detect respective average picture levels of the first and second picture signals respectively thus producing first and second level detection signals, an ABL detector for generating a detection voltage responsive to a variation in an anode current of the cathode ray tube, and control means for controlling at least one of contrasts and brightnesses of the first end second picture signals by commonly operating on the first and second picture signals in response to the detection voltage from the ABL detector as well as for independently controlling at least one of contrasts and brightnesses of the first and second picture signals in response to the first and second detection signals from the APL detector.