Is the frequency noise of an oscillator of deterministic origin?

We report on a new multifractal type approach of low-frequency noise in oscillators. The time sequence is interrogated by means of a multiscale local stability exponent which acts in a sliding filtering window. Its discontinuities are reflected into a binary coding in which the correlations are analyzed. The mapping of binary data into a devil's staircase is used to emphasize the correlated and possibly deterministic origin of frequency fluctuations in quartz oscillators.