User`s guide

Using Frequency-Response Plots to Validate Models
How to Plo
tBodePlotsUsingtheGUI
To create
a frequency-response plot for parametric linear models in the System
Identific
ation Tool GUI, select the Frequency resp check box in the Model
Views ar
ea. For general information about creating and working w ith plots,
see “Wor
king with Plots in the System Identification Tool GUI” on page 12-15.
To inclu
de or exclude a model on the plot, click the corresponding model icon
in the Sy
stem Identification Tool GUI. Active models displ ay a thick line
inside t
he Model Board icon.
In addi
tion to the frequency-response curve, you can display a confidence
interv
al on the plot. The confidence interval corresponds to the range of
respon
se values with a specific p robability of being the actual response of the
system
. The toolbox uses the estimated uncertainty in the m odel parameters
to cal
culate confidence intervals and assumes the estimates have a Gaussian
distr
ibution.
For ex
ample, for a 95% confidenceinterval,theregionaroundthenominal
curve
represents the range of values that have a 95% probability of being the
8-35