Miller effect voltage sensitive capacitance afc system

Claim 1

IN AN AUTOMATIC CONTROL CIRCUIT INCLUDING A SOURCE OF REFERENCE SIGNAL, A GENERATOR HAVING A RESONANT TANK CIRCUIT FOR PRODUCING A LOCAL SIGNAL THE FREQUENCY AND PHASE OF WHICH MAY BE VARIED, AND MEANS FOR COMPARING THE FREQUENCY AND PHASE OF SAID REFENCE SIGNAL AND SAID LOCAL SIGNAL TO DERIVE AN ERROR SIGNAL INDICATIVE OF THEIR FREQUENCY AND PHASE RELATION, THE IMPROVEMENT COMPRISING: A TRANSISTOR HAVING EMITTER, BASE, AND COLLECTOR ELECTRODES; A VOLTAGE SENSITIVE CAPACITOR COUPLED BETWEEN SAID BASE AND SAID COLLECTOR ELECTRODES, SAID CAPACITOR ALSO BEING COUPLED TO SAID COMPARISON MEANS AND HAVING AN INSTANTANEOUS CAPACITANCE WHICH VARIES WITH VARIATIONS IN SAID ERROR SIGNAL; AND MEANS VARYING THE FREQUENCY AND PHASE OF SAID OSCILLATOR, INCLUDING MEANS FOR COUPLING SAID BASE ELECTRODE TO SAID TANK CIRCUIT TO PRESENT TO SAID TANK CIRCUIT AN IMPEDANCE SUBSTANTIALLY EQUAL TO THE PRODUCT OF THE AMPLIFICATION FACTOR OF SAID TRANSISTOR AND THE INSTANTANEOUS VALUE OF SAID CAPACITANCE.