Amplitude control circuit for transistor oscillators

Claim 1

IN A TRANSISTOR OSCILLATOR INCLUDING A TRANSISTOR, A TUNED CIRCUIT COUPLED TO THE COLLECTOR OF SAID TRANSISTOR TO PRODUCE OUTPUT OSCILLATIONS AT A PREDETERMINED FREQUENCY, A D.C. BIAS VOLTAGE SOURCE COUPLED TO THE BASE OF SAID TRANSISTOR, AND MEANS FOR APPLYING A FEEDBACK SIGNAL FROM THE COLLECTOR TO THE BASE OF SAID TRANSISTOR TO SUSTAIN SAID OSCILLATIONS, THE IMPROVEMENT COMPRISING AN AMPLITUDE CONTROL CIRCUIT INCLUDING AN INDUCTIVE CIRCUIT ELEMENT COUPLED IN SERIES BETWEEN THE BASE OF SAID TRANSISTOR AND SAID D.C. BIAS VOLTAGE SOURCE, A CAPACTIVE CIRCUIT ELEMENT COUPLED BETWEEN THE BASE AND THE EMITTER OF SAID TRANSISTOR, MEANS FOR APPLYING SAID FEEDBACK SIGNAL FROM THE COLLECTOR CIRCUIT OF SAID TRANSISTOR TO SAID INDUCTIVE AND CAPACITIVE CIRCUIT ELEMENTS, SAID INDUCTIVE AND CAPACITIVE CIRCUIT ELEMENTS BEING OF SUCH VALUE AS TO PRODUCE A PREDETERMINED INITIAL TRANSFER CHARACTERISTICS BETWEEN THE INPUT AND OUTPUT OF SAID TRANSISTOR, ONE OF SAID CIRCUIT ELEMENTS BEING VARIABLE IN VALUE, AND MEANS FOR VARYING THE VALUE OF SAID VARIABLE CIRCUIT ELEMENT TO VARY THE AMPLITUDE OF SAID OUTPUT OSCILLATIONS WITHOUT SIGNIFICANTLY ALTERING THE FREQUENCY THEREOF BY VARYING SAID TRANSFER CHARACTERISTIC.