The autocorrelation technique is a method for estimating the dominating frequency in a complex signal, as well as its variance.
Specifically, it calculates the first two moments of the power spectrum, namely the mean and variance.
The algorithm is both computationally faster and significantly more accurate compared to the Fourier transform, since the resolution is not limited by the number of samples used.
The autocorrelation of lag 1 can be expressed using the inverse Fourier transform of the power spectrum
: If we model the power spectrum as a single frequency