User`s guide

8 Model Analysis
For frequency-domain validation data, the plot shows the following two axes:
• Estimated power spectrum of the residuals for each output
• Transfer-function amplitude from the input to the residuals for each
input-output pair
For linear models, you can estimate a model using time-domain data, and
then validate the model using f requen cy domain data. For nonlinear models,
the System Identification Toolbox product suppo rts only time-do main data.
The following figure show s a sample Residual Analysis plot, created in the
System Identification Tool GUI.
Displaying the Confidence Interval
You can display a confidence interval on the plot in the GUI to gain insight
into the quality of the model. To learn how to show or hide confi dence
interval, see the description of the plot setting s in “H ow to Plot Residuals
Using the GUI” on page 8-19.
8-18