Abstract: The high frequency circuit includes an oscillator connected in a Colpitts configuration. Negative feedback to the oscillator is applied through an amplifier, both to stabilize the circuit and to permit frequency modulation of the carrier signal generated by the circuit. This feedback incorporates a capacitance to neutralize the Miller effect, thereby enabling it to operate at exceedingly high carrier frequencies. A variation of the circuit permits it to be simultaneously controlled by both a voltage and a current control signal. Also, by applying a frequency modulated carrier signal at a particular node of the oscillator, a demodulated output signal may be obtained.