Multifrequency generators

Claim 1

IN A MULTIFREQUENCY GENERATOR, THE COMBINATION COMPRISING A STABLE FREQUENCY SOURCE, MEANS RESPONSIVE TO SAID SOURCE FOR PRODUCING THE HARMONICS OF THE SIGNAL OUTPUT OF SAID SOURCE, A SECOND SOURCE INCLUDING A VARIABLE FREQUENCY OSCILLATOR, MEANS FOR COMPARING THE PHASE OF THE OUTPUT SIGNAL FROM SAID HARMONIC PRODUCING MEANS TO THAT OF THE OUTPUT SIGNAL FROM SAID SECOND SOURCE AND PRODUCING A DIRECT-CURRENT VOLTAGE THAT IS DIRECTLY PROPORTIONAL TO THE PHASE DIFFERENCE, SAID OSCILLATOR OF SAID SECOND SOURCE HAVING A FREQUENCY DETERMINING CIRCUIT COMPRISING A PERMANENTLY CONNECTED INDUCTOR IN PARALLEL WITH A PERMANENTLY CONNECTED CAPACITOR, MEANS FOR CHANGING THE FREQUENCY OF OPERATION OF SAID OSCILLATOR COMPRISING A PLURALITY OF INDUCTOR AND CAPACITOR COMBINATIONS INSERTABLE IN SAID FREQUENCY DETERMINING CIRCUIT, SAID INDUCTORS BEING INSERTABLE IN PARALLEL WITH SAID PERMANENTLY CONNECTED INDUCTOR AND SAID CAPACITORS BEING INSERTABLE IN SERIES WITH SAID PERMANENTLY CONNECTED CAPACITOR, SAID COMBINATIONS HAVING ESSENTIALLY EQUAL INDUCTANCE TO CAPACITANCE RATIO, AND MEANS FOR FINELY TUNING SAID OSCILLATOR BY LOCKING ITS FREQUENCY OF OPERATION TO ONE OF THE FREQUENCIES IN THE SIGNAL OUTPUT OF SAID HARMONIC PRODUCING MEANS, SAID FINE TUNING MEANS COMPRISING A VARIABLE CAPACITOR CONNECTED IN PARALLEL WITH SAID FIRST CAPICTOR AND HAVING A VALUE OF CAPACITANCE DETERMINED BY A VOLTAGE APPLIED THERETO, AND MEANS FOR APPLYING THE DIRECT-CURRENT OUTPUT VOLTAGE FROM SAID COMPARING MEANS TO SAID VARIABLE CAPACITOR.