Low phase noise reference oscillator

摘要

A phase-locking oscillator circuit having improved phase noise characteristics is disclosed herein. The oscillator circuit includes a tuned oscillator for providing a carrier signal at a tunable carrier frequency. The carrier signal is applied to an input port of a phase modulator operative to impress an RF signal upon output terminal. An error detection and feedback network generates an error signal by comparing a predefined characteristic of the RF output signal to a reference signal. The network includes a loop filter arrangement which operates upon the error signal so as to provide a tuned oscillator tuning signal to a tuning port of the tuned oscillator and a modulator control signal to a control port of the phase modulator. In an exemplary implementation the error detection and feedback network includes a phase detector for generating the error signal in response to the phase difference between the RF output signal and the reference signal.