The effect of operating parameters and oscillator characteristics upon the phase angle between a locked X-band Gunn oscillator and its locking signal

Experiments have been carried out to measure the phase angle between a locked negative-resistance (Gunn) oscillator and its locking oscillator. Phase angle has been measured as a function of ambient temperature, oscillator bias voltage, locking power, and the voltage applied to a varactor tuning diode coupled into the locked oscillator. Results indicate that given a knowledge of the oscillator characteristics and the operating conditions, it is possible to predict, with reasonable accuracy, the phase of the locked oscillator. The relative merits of various methods of phase control are discussed and it is concluded that the best method is to use a varactor diode coupled into the negative-resistance oscillator.