The Noise spectrum plot is opened by checking the corresponding check box in the ident window.

The plots show the disturbance spectra of the selected models.

For input-output models the disturbance spectrum is defined as the spectrum of w in the description

y(t) = G(q) u(t) + w(t)

For time series models

y(t) = H(q) e(t)

the shown spectrum is that of y itself.

The output number (channel) selector (y1, etc.) refers to the chosen output component of the spectrum. Cross spectra between different outputs are not accessible.

Help topics.

(file idspect.hlp)