System Identification Toolbox

Poles and Zeros

The poles of a system are the roots of the denominator of the transfer function G(z), while the zeros are the roots of the numerator. In particular the poles have a direct influence on the dynamic properties of the system.

The poles and zeros of G (and H ) are plotted by choosing the Model View Poles and Zeros.

It is useful to turn on the confidence intervals in this case. They will clearly reveal which poles and zeros could cancel (their confidence regions overlap). That is an indication that a lower order dynamic model could be used.

For multivariable systems it is the poles and zeros of the individual input/output channels that are displayed. To obtain the so called transmission zeros, you will have to export the model and then apply the command tzero, provided you have the Control Systems Toolbox.

Transient Response

Compare Measured and Model Output