Measurement of external Q factor of microwave oscillators using frequency pulling or frequency locking

Conditions are identified for the measurement of the external Q factor of microwave oscillators by use of frequency pulling or locking techniques. A small modification to a technique proposed previously for frequency locking is derived, and is extended to the case of frequency pulling. It is shown that measurements of the full locking or pulling bandwidths give information on the first derivatives, with respect to r.f.-voltage amplitude, of the device susceptance and conductance.