Bode analysis comprises graphical representations of
magnitude and phase information, both plotted as a function of frequency
(*w*). Bode plots clearly illustrate the relative stability of a system.
Gain and phase margin requirements of a closed-loop system are often defined in
terms of Bode plots.

Bode plots have a variety of applications, including:

• Analysis of system closed-loop performance characteristics

• Determination of resonant frequencies and maximum power amplitude

Bode plots can also be used for the specification and design of compensators.

Analyze > Frequency Response lets you set the phase and gain margins before displaying the Bode phase and magnitude plots, like the ones shown below:

Both plots are relative to log frequency (rad/s units). The magnitude units are log and the phase units are degrees.

**To generate Bode magnitude and
phase plots**

1. Prepare the system linearization.

2.
Choose **Analyze >
Frequency Range** to define the range and resolution of the natural

3.
Choose **Analyze** **>** **Frequency** **Response** to set the
phase and gain margins and create the Bode phase and magnitude plots.

4. Resize or zoom in on the plot for better viewing.