Automatic frequency control means for single-sideband receivers and the like

Claim 1

IN RADIANT ENERGY RECEIVING EQUIPMENT SUBJECT TO OCCASIONAL FADING OF THE RECEIVED SIGNAL AND HAVING A LOCAL OSCILLATOR ESTABLISHING A PREDETERMINED IF FREQUENCY FOR THE EQUIPMENT, AUTOMATIC FREQUENCY CONTROL MEANS COMPRISING MEANS SELECTING AND ISOLATING A SAMPLE OF A SIGNAL CARRIER COMPONENT FREQUENCY, MEANS GENERATING A STABLE REFERENCE FREQUENCY, MEANS COMPARING SAID CARRIER COMPONENT FREQUENCY AND SAID REFERENCE FREQUENCY AND DEVELOPING A CORRECTION SIGNAL RELATED TO THE FREQUENCY DIFFERENCE BETWEEN SAID CARRIER COMPONENT FREQUENCY AND SAID STABLE REFERENCE FREQUENCY, CORRECTION SIGNAL STORAGE MEANS TO WHICH SAID CORRECTION SIGNAL IS FED DURING PERIODS WHEN THE INCOMING CARRIER LEVEL IS GREATER THAN A PREDETERMINED VALUE AND FROM WHICH A STORED CORRECTION SIGNAL IS AVAILABLE TO MAINTAIN SAID IF FREQUENCY SUBSTANTIALLY CONSTANT FOR A SUBSTANTIAL PERIOD WHEN THE INCOMING CARRIER LEVEL IS LESS THAN SAID PREDETERMINED VALUE, AND REACTION OSCILLATOR MEANS RESPONSIVE TO SAID CORRECTION SIGNAL FOR VARYING SAID LOCAL OSCILLATOR IN A MANNER MAINTAINING SAID IF FREQUENCY SUBSTANTIALLY CONSTANT, SAID CORRECTION SIGNAL STORAGE MEANS COMPRISING A VOLTAGE DIVIDER NETWORK INCLUDING A FIRST CAPACITANCE CHARGED BY SAID CORRECTION SIGNAL TO A VALUE SOMEWHAT LESS THAN THE VOLTAGE OF THE CORRECTION SIGNAL, SAID SIGNAL STORAGE CIRCUIT FURTHER COMPRISING A SECOND CAPACITANCE CHARGED BY SAID CORRECTION VOLTAGE TO SUBSTANTIALLY THE FULL VALUE OF SAID CORRECTION VOLTAGE, SAID STORAGE CIRCUIT FURTHER COMPRISING SWITCH MEANS OPERATED IN RESPONSE TO THE INCOMING CARRIER LEVEL TO APPLY TO VOLTAGE ACROSS SAID FIRST CAPACITANCE TO SAID CORRECTION REACTANCE MEANS WHEN SAID INCOMING CARRIER LEVEL IS ABOVE A PREDETERMINED VALUE, AND OPERABLE TO APPLY TO VOLTAGE ACROSS SAID SECOND CAPACITANCE TO SAID CORRECTION REACTANCE MEANS DURING A PERIOD WHEN SAID INCOMING CARRIER LEVEL IS LESS THAN A PREDETERMINED VALUE.