Improvements of the Procedures Used to Study the Fluctuations of Oscillators

Considering that procedures currently used to study the fluctuations in oscillators do not give directly useful results, we have tried to define a procedure more suitable for experimentalists. We have tempted to obtain a function σ(T) which would be a kind of variance of the frequency fluctuations observed in a duration T. Taking a frequency domain point of view, we find a procedure which can yield also an estimation of the spectral density of the frequency.