Good test for periodicity between signals
Something you could do is calculate the FFT of both signals and define some criterion for periodicity. For example, you pick the highest component of each FFT and compare the two (one from each signal) and thus determine which is more &quot;periodic&quot;. You could consider an average of all the FFT components and compare. This would be a rather robust solution, since the FFT calculates the frequency decomposition of a signal.