Phase controlled oscillator loop including an electronic counter

Claim 1

APPARATUS FOR CONTROLLING THE FREQUENCY OF OPERATION OF A VARIABLE FREQUENCY OSCILLATOR COMPRISING A VARIABLE FREQUENCY OSCILLATOR FOR PRODUCING A CONTINUOUS PULSE SEQUENCE OF A FIRST FREQUENCY, A FREQUENCY TRANSFORMER FOR PRODUCING A CONTINUOUS PULSE SEQUENCE OF A SECOND FREQUENCY CONNECTED TO THE OUTPUT OF THE VARIABLE FREQUENCY OSCILLATOR, AN ELECTRONIC COUNTER HAVING A CERTAIN TOTAL PULSE CAPACITY, CONTROL MEANS COMPRISING AN ADJUSTABLE COINCIDENCE CIRCUIT CONNECTED TO THE COUNTER FOR ALLOWING A GIVEN NUMBER OF PULSES OF THE FIRST FREQUENCY TO BE COUNTED INTO THE COUNTER, THEREUPON SWITCHING TO ALLOW PULSES OF THE SECOND FREQUENCY TO BE COUNTED INTO THE COUNTER UNTIL THE TOTAL PULSE CAPACITY OF THE COUNTER IS REACHED, THE ARRANGEMENT BEING SUCH THAT UPON REACHING ITS TOTAL PULSE CAPACITY THE COUNTER TURNS TO ZERO AND EMITS AN OUTPUT PULSE, THE FREQUENCY IN THE OUTPUT PULSES FROM THE COUNTER BEING COMPARED WITH A REFERENCE FREQUENCY AND THE DIFFERENCE USED TO ADJUST THE FREQUENCY OF THE OSCILLATOR SO AS TO MINIMIZE THIS DIFFERENCE.