In my slides about signal processing, there is one that mentions the same thing as the beginning of this and this answer, namely that the Fourier transform of a signal, squared is the power spectrum density of the signal.
In this talk, it is mentioned that coherence is calculated by dividing the squared cross-spectrum by the product of the two auto-spectra.
However, the formula in my slides divides the squared cross-spectrum by the product of the formula of our previously seen PSD and another PSD.
So, is autospectrum the same as PSD? I can find a lot of information about PSD, but not on autospectrum.