Which state is being plotted in multi-degree of freedom system when using bodeplot

I am using bodeplot to get frequency response curves of a 2 degree of freedom system. I use the command

>>bodeplot(sys)

and it returns a frequency response curve and a phase angle curve. sys is a state space model.

My question is, for which state is it plotting the response? There are four states but I only get one set of plots(frequency and phase). And, how to I select the state I want?

Answer 1

[Raj]

Can you share your system. 'bode' or 'bodeplot' for a MIMO statespace system will give you Bode plot (Magnitude and Frequency response) from each input to each output like this example:

A=rand(2,2)
B=rand(2,2)
C=eye(size(A))
D=zeros(size(B))
system=ss(A,B,C,D)
bodeplot(system)

will give you a plot like this:

[Drew Mitchell]

Thanks for the response. I had the wrong output matrix.