The Data Spectra Plot is opened by checking the corresponding check box in the ident window.
The plot shows the spectra of the output and input signals of selected data sets.
The method of computing/estimating the spectra is set using the Periodogram and Spectral analysis mutually exclusive checkmenus under the Options menu.
When Spectral analysis is chosen, the method and resolution parameter is determined by the current choice under popup menu Estimate > Spectral model in the ident window.
The periodogram is the absolute square of the Fourier transform of the data sequence.
(file iduyspe.htm)