How to activate the code command gershband(sys)

Dear colleagues

I am using matlab code to plot the the Gershgorin circles at different frequencies

G=tf({14.96 [95150 95150*1.898];85.2 [124000 124000*2.037]},{[1 12 20] [1.0000 103.2250 325.0250 252.5000];[1 12 20] [1.0000 103.2250 325.0250 252.5000]}); % Transfer Function Matrix
k1=[1000 0;0 1];% first precompensator
k2=tf({[-1.57 -1.57*20.6] [1.205 1.205*11.6];[1.08 1.08*146.3] [-0.189 -0.189*101.4]},{[1 158.5] [1 158.5];[1 158.5] [1 158.5]});%2nd Compensator
Q=inv(G*k1*k2);% Inversed Overall Transfer Function Matrix
gershband(Q);% creates Figures gershgorin circles

Unfortunately I am getting the following error message:

Undefined function or variable 'gershband'.

Any can guide me how can i get this command working, what additional app. should I add to my matlab software.

Regards,

Basim Touqan

Answer 1

[Star Strider]

You have to download the MIMO Toolbox (link) from the File Exchange to use the function. You also have to give it the ‘a,b,c,d,e’ matrices as arguments, not a system object.

Note that it was written in 2006 and apparently has not been updated since, so you could have problems with it.