System identification from Bode plot

1. Which information can we obtain from the Bode plot?
2. How do you find the damping ratio on a Bode plot?
3. What is the code for Bode plot in Matlab?

Which information can we obtain from the Bode plot?

Bode plots show the frequency response, that is, the changes in magnitude and phase as a function of frequency. This is done on two semi-log scale plots. The top plot is typically magnitude or “gain” in dB. The bottom plot is phase, most commonly in degrees.

How do you find the damping ratio on a Bode plot?

Identifying a System from the Bode Plot

The damping ratio of a system can be found with the DC Gain and the magnitude of the bode plot when the phase plot is -90 degrees.

What is the code for Bode plot in Matlab?

h = bodeplot( sys ) plots the Bode magnitude and phase of the dynamic system model sys and returns the plot handle h to the plot. You can use this handle h to customize the plot with the getoptions and setoptions commands.