Television brightness and contrast control circuit

Claim 1

IN A COLOR TELEVISION SIGNAL RECEIVING SYSTEM, THE COMBINATION COMPRISING, A COLOR KINESCOPE, SIGNAL TRANSLATING MEANS FOR PROCESSING A RECEIVED SIGNAL TO PROVIDE A VIDEO SIGNAL, A VIDEO SIGNAL AMPLIFIER FOR COUPLING SAID SIGNAL TRANSLATING MEANS TO SAID KINESCOPE, MEANS COUPLED WITH SAID KINESCOPE FOR SENSING THE AVERAGE KINESCOPE BEAM CURRENT FLOWING THEREIN, INCLUDING A HIGH VOLTAGE SUPPLY CIRCUIT FOR SAID KINESCOPE PROVIDING A B-BOOST VOLTAGE SIGNAL THAT IS PROPORTIONAL TO THE AVERAGE KINESCOPE BEAM CURRENT, MEANS RESPONSIVE TO AT LEAST A PORTION OF SAID B-BOOST VOLTAGE SIGNAL FOR ALTERING THE BIAS ON THE GUNS OF SAID KINESCOPE, INCLUDING A SOURCE OF VERTICAL RETRACE PULSES, AMPLITUDE SELECTIVE MEANS COUPLED BETWEEN SAID SOURCE OF RETRACE PULSES AND SAID HIGH VOLTAGE SUPPLY TO PASS PORTIONS OF SAID RETACE PULSES THAT VARY IN AN AMOUNT PROPORTIONAL TO SAID B-BOOST VOLTAGE, AND MEANS COUPLED TO SAID AMPLITUDE SELECTIVE MEANS FOR PEAK DETECTING THE PASSED PORTIONS OF SAID RETRACE PULSES TO PROVIDE A D.C. CONTROL VOLTAGE INVERSELY PROPORTIONAL TO KINESCOP BEAM CURRENT.