Mark poles and zeroes on bode plot

For a transfer function, I am able to determine its pole and zeroes by using the 'pzmap' command. When I generate the bode of the transfer function, I want to mark the pole with 'x' and zero with 'o' on the bode's magnitude graph. I can write a program to do so but I am wondering if there is a command available already that can display the pole and zero location on the bode plot itself.

Answer 1

[Jerin John]

The easiest way I have found to do this is to use the SISO Design Tool GUI. If plant is your transfer function, just give the command

sisotool(plant)

Then the tool GUI opens together with a root locus and bode plot of the open loop plant. This bode plot will have the poles and zeros marked on it like you explained.

Now, to remove the root locus plot and have only the open loop bode plot, goto the Graphical Tuning tab in the main GUI of sisotool and select Plot1 as Open-Loop Bode and all other plots as None. After this press the button Show Design Plot. Now you will have the plot as you needed in the sisotool. You can right click on this plot and change other available options as you wish. Then, from the menu File>Print to Figure, you can convert this to a normal Matlab figure.