Circuit for hue control in a color television receiver

Claim 1

IN A COLOR TELEVISION RECEIVER FOR RECEIVING COLOR TELEVISION SIGNALS OF THE TYPE IN WHICH TWO COLOR SIGNALS ARE MODULATED IN QUADRATURE ON A SUBCARRIER WAVE, AND SYNCHRONIZING SIGNALS ARE PROVIDED BETWEEN SCANNING LINES, AND WHEREIN SAID SYNCHRONIZING SIGNALS INCLUDE SUBCARRIER OSCILLATIONS AND HAVE A BLACK LEVEL, MEANS FOR DEMODULATING SAID TELEVISION SIGNALS COMPRISING FIRST AND SECOND SYNCHRONOUS DEMODULATOR MEANS, REFERENCE OSCILLATOR MEANS FOR PROVIDING REFERENCE OSCILLATIONS, MEANS FOR APPLYING SAID REFERENCE OSCILLATIONS AND TELEVISION SIGNALS TO SAID FIRST AND SECOND SYNCHRONOUS DEMODULATOR MEANS WHEREBY THE REFERENCE OSCILLATIONS APPLIED TO SAID FIRST SYNCHRONOUS DEMODULATOR MEANS ARE IN QUADRATURE WITH THE REFERENCE OSCILLATIONS APPLIED TO SAID SECOND SYNCHRONOUS DEMODULATOR MEANS, MEANS CONNECTED TO SAID REFERENCE OSCILLATOR MEANS FOR CONTROLLING THE PHASE OF SAID REFERENCE OSCILLATIONS, COMPARATOR MEANS, COMPRISING FIRST AND SECOND UNILATERALLY CONDUCTIVE DEVICES HAVING CONTROL ELECTRODES AND OUTPUT ELECTRODES, A SOURCE OF GATING SIGNALS CONNECTED TO SAID COMPARATOR MEANS FOR RENDERING SAID COMPARATOR OPERATIVE ONLY DURING THE TIME BETWEEN SCANNING LINES, MEANS FOR APPLYING THE OUTPUT OF SAID FIRST DEMODULATOR MEANS TO SAID COMPARATOR MEANS FOR COMPARING THE AMPLITUDE OF THE OUTPUT SIGNALS OF SAID FIRST DEMODULATOR MEANS DURING THE OCCURRENCE OF SAID SUBCARRIER OSCILLATIONS WITH THE LEVEL OF SAID BLACK LEVEL TO PROVIDE A CONTROL VOLTAGE, MEANS FOR APPLYING SAID CONTROL VOLTAGE TO SAID MEANS FOR CONTROLLING THE PHASE OF SAID REFERENCE OSCILLATIONS, MEANS FOR APPLYING THE OUTPUT SIGNALS OF SAID FIRST DEMODULATOR MEANS TO SAID CONTROL ELECTRODES OF SAID UNILATERALLY CONDUCTIVE DEVICE, AN OSCILLATORY CIRCUIT CONNECTED BETWEEN SAID OUTPUT ELECTRODES, SAID OSCILLATORY CIRCUIT HAVING A FREQUENCY THAT IS A HARMONIC OF THE LINE FLYBACK FREQUENCY OF SAID TELEVISION SIGNALS, MEANS FOR DAMPING SAID OSCILLATORY CIRCUIT EXCEPT DURING THE TIME BETWEEN SCANNING LINES, AND MEANS CONNECTED TO AT LEAST ONE OF SAID OUTPUT ELECTRODES FOR PROVIDING SAID CONTROL VOLTAGE.