Autospectrum (Peak)

Instead of averaging all the FFT spectra, this variant of the autospectrum keeps the maximum magnitude at each frequency across all the spectra.

The formula used for the autospectrum (peak) calculation in SAS is:

Where,
  • FT is the Fourier Transform of the signal (mathematical function).
  • wl is the window size.
  • w is the analysis window (of length wl samples).
  • nfft is the number of samples used to calculate the FFT on the windowed signal.
  • Fs is the sampling frequency of the analyzed signal.
Note: In versions of SAS prior to 2022 R2, Autospectrum (Peak) corresponds to the settings combination {Autospectrum normalization, Peak calculation}.

Refer to the Display Options for the Spectrum Window to learn how to display the autospectrum.