User`s guide

8 Model Analysis

Using Model Output Plots to Validate and Compare Models

In this section...

“Supported Model Types” on page 8-8

“What Does a Mo del Ou tput Plot Show?” on page 8-8

“Choosing Simulated or Predicted Output” on page 8-9

“How to Plot M odel Output U sing the G UI” on page 8-11

“Displaying the Conﬁdence Interval” on page 8-13

“How to Plot and Compare Model Output at the Command Line” on page

8-14

Supported Model Types

You can validate line ar pa ra metric models and non linear models by checking

how w ell the simulated or predicted output of the m odel matches the

measured output.

Note For nonparametric models, including impulse-response, step-response,

and frequency-response models, model output plots are not available. For

time-series m odels , you can only generate model-output plots for parametric

models using time-domain time-serie s (no input) measured d ata.

What Does a Model Output Plot Show?

The model output plot show s differe nt information depending on the domain

of the input-output validation data, as follows:

• For time-domain validation data, the plot shows simulated or predicted

model output.

• For frequency-domain data, the plot shows the simulated complex-valued

amplitude of the model output. The complex-valued amplitude is equal to

the product of the Fourier transform of the input and the model frequency

function.

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