Multiple frequency oscillator utilizing plural feedback loops

Claim 1

AN OSCILLATOR CIRCUIT COMPRISING AN AMPLIFIER HAVING AN INPUT TERMINAL AND AN OUTPUT TERMINAL AND A PLURALITY OF POSITIVE FEEDBACK CIRCUITS COUPLED BETWEEN THE OUTPUT TERMINAL AND THE INPUT TERMINAL, SAID AMPLIFIER CIRCUIT INCLUDING THREE TRANSISTORS EACH HAVING AN EMITTER ELECTRODE, A BASE ELECTRODE AND A COLLECTOR ELECTRODE, A FIRST OF THE TRANSISTORS BEING CONNECTED AS AN EMITTER FOLLOWER WITH THE COLLECTOR ELECTRODE THEREOF CONNECTED DIRECTLY TO A FIRST REFERENCE POTENTIAL, SAID FIRST TRANSISTOR HAVING THE BASE ELECTRODE THEREOF DIRECTLY CONNECTED TO THE INPUT TERMINAL OF THE AMPLIFIER, A FIRST RESISTIVE ELEMENT COUPLED BETWEEN THE EMITTER ELECTRODE OF THE FIRST TRANSISTOR AND A SECOND REFERENCE POTENTIAL, THE EMITTER ELECTRODE OF THE FIRST TRANSISTOR BEING DIRECTLY COUPLED TO THE EMITTER ELECTRODE OF THE FIRST TRANSISTOR, A SECOND RESISTIVE ELEMENT COUPLED BETWEEN THE COLLECTOR ELECTRODE OF THE SECOND TRANSISTOR AND THE FIRST REFERENCE POTENTIAL, A THIRD RESISTIVE ELEMENT COUPLED BETWEEN THE BASE ELECTRODE OF THE SECOND TRANSISTOR AND GROUND POTENTIAL, THE BASE ELECTRODE OF THE THIRD TRANSISTOR BEING COUPLED DIRECTLY TO THE COLLECTOR ELECTRODE OF THE SECOND TRANSISTOR, THE COLLECTOR ELECTRODE OF THE THIRD TRANSISTOR BEING DIRECTLY CONNECTED TO THE FIRST REFERENCE POTENTIAL, A FOURTH RESISTIVE ELEMENT COUPLED BETWEEN THE BASE ELECTRODE OF THE SECOND TRANSISTOR AND THE EMITTER ELECTRODE OF THE THIRD TRANSISTOR, A FIFTH RESISTIVE ELEMENT COUPLED BETWEEN THE EMITTER ELECTRODE OF THE THIRD TRANSISTOR AND THE SECOND REFERENCE POTENTIAL, EACH OF THE FEEDBACK CIRCUITS COMPRISING A FREQUENCY SELECTIVE MEANS AND A SIGNAL LIMITING MEANS CONNECTED IN SERIES BETWEEN THE OUTPUT TERMINAL AND THE INPUT TERMINAL OF THE AMPLIFIER, THE FREQUENCY SELECTIVE MEANS OF AT LEAST ONE OF THE FEEDBACK CIRCUITS INCLUDING A TUNED CIRCUIT INCLUDING A MEANS FOR VARYING THE TUNING THEREOF AT AN AUDIO RATE WHEREBY THE FEEDBACK SIGNAL THEREFROM IS FREQUENCY MODULATED.