Evaluation of Oscillator Quality

A general type of oscillator is considered, which results from the combination of an active element with a selective network. Amplitude and frequency are deduced by a simple method, valid for quasi-sinusoidal oscillation. If the oscillator is perturbed, relative amplitude and frequency variations can be calculated. Their product depends only upon the perturbation itself and a coefficient which is a function of the selective network. It seems apt to choose this coefficient as the figure of merit of the oscillator. For ordinary LC oscillators it is approximately equal to the Q. Values are calculated for certain RC oscillators. Some experiments confirm the results.