Plot the real and imaginary part of FRF vs Frequency using freqresp(system, w)?

Question

Maral Dorri 2020-3-30

0
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https://ww2.mathworks.cn/matlabcentral/answers/513836-plot-the-real-and-imaginary-part-of-frf-vs-frequency-using-freqresp-system-w

回答： Navya Seelam 2020-4-1

I have a three story shear building with the following system matrix. i use the following code to get the real and imaginary parts of the FRF but I get the error: Not enough input arguments.

M = [1 0 0;0 2 0;0 0 2];
K = [100 -100 0;-100 200 -100;0 -100 250];
C = 0.03*M;
% State Space Representation
I = [1 0 0;0 1 0;0 0 1];
zeros = zeros(3);
A = [zeros I; (-1*inv(M)*K) (-1*inv(M)*C)];
M1st = [0 0 0;0 0 0;0 0 0.5];
B = [zeros; M1st];
Ca = [(-1*inv(M)*K) (-1*inv(M)*C)];    
Da = M1st;
System = ss(A,B,Ca,Da);
w = logspace(1,2,200);
H = freqresp(system, w)