Noise cancellation circuit

Claim 1

IN COMBINATION IN A TELEVISION RECEIVER INCLUDING MEANS FOR PRODUCING A COMPOSITE VIDEO SIGNALS HAVING INFORMATION COMPONENTS AND PERIODIC REFERENCE COMPONENTS FROM A RECEIVED TELEVISION SIGNALS, SAID REFERENCE COMPONENS BEING GREATER IN MAGNITUDE THAN SAID INFORMATION COMPONENTS, SAID TELEVISION SIGNAL BEING SUBJECT TO UNDESIRED SPURIOUS COMPONENTS OF GRETER MAGNIUTDE THAN SAID REFERENCE COMPONENTS; A VIDEO AMPLIFIER AND A LOAD RESISTOR THEREFOR; MEANS FOR APPLYING SAID COMPOSITE SIGNAL TO SAID VIDEO AMPLIFIER; A NOISE INVERTER TUBE FOR INVERTING AND CANCELLING SAID SPURIOUS COMPONENTS INCLUDING AN ANODE, A CATHODE AND A CONTROL RIGID; A RESISTOR CONNECED BETWEEN A POINT INTERMEDIATE THE ENDS OF SAID VIDEO AMPLIFIER LOAD RESISTOR AND SAID ANODE FOR COUPLING THE OUTPUT OF SAID VIDEO AMPLIFIER TO SAID NOISE INVERTER ANODE AT REDUCED LEVEL; MEANS FOR COUPLING SAID COMPOSITE VIDEO SIGNAL TO SAID CATHODE AT A REDUCED LEVEL; MEANS FOR APPLYING A CONSTANT DIRECT CURRENT BIAS TO SAID CONTROL GRID WHEREBY SAID NOISE INVERTER TUBE ONLY CONCUCTS ON SIGNALS OF GREATER MAGNITUDE THAN SAID REFERENCE COMPONENTS; CONTROL VOLTAGE MEANS COUPLED TO SAID VIDEO AMPLIFIER LOAD RESISTOR FOR DEVELOPING A CONTROL VOLTAGE IN ACCORDANCE WITH THE MAGNITUDE OF SAID REFERENCE COMPONENTS; MEANS IN SAID VIDEO AMPLIFIER, AND RESPONSIVE TO THE CONDUCTION CURRENT IN SAID VIDEO AMPLIFIER, COUPLED TO SAID CONTROL VOLTAGE FOR CONVEYING INFORMATION REGARDING CHANGES IN SAID CONDUCTION CURRENT THERETO; AND MEANS FOR COUPLING SAID CONTROL VOLTAGE TO SAID CONTROL GRID WHEREBY THE CONDUCTION LEVEL OF SAID NOISE INVERTER TUBE IN AUTOMATICALLY ADJUSTED AS THE LEVEL OF SAID COMPOSITE VIDEO SIGNAL VARIES.