多输入多输出系统已知状态方程如何画频响函数图

gumengyinyin

多输入多输出系统已知状态方程如何画频响函数图。
KM=inv(M)*K ;          %动力矩阵
[P,W2]=eig(KM);       %求解特征值 和特征向量
f=sqrt(W2)/(2*pi); %固有频率
m1=eye(7);
CM=inv(M)*C;
m0=zeros(7,7);
m01=zeros(1,7);
A=[m0 m1;-KM -CM];
B=[0 0
   0 0
   0 0
   0 0
   0 0
   0 0
   0 0
   0 0
   0 0
   1/1105*2*(kqz+khz) 1/1105*2*(cqz+chz)
   0 0
   0 0
   0 0
   0 0];
% [X,w]=freqz(A,B)
C=[1 0 0 0 0 0 0 0 0 0 0 0 0 0
   0 1 0 0 0 0 0 0 0 0 0 0 0 0
   0 0 1 0 0 0 0 0 0 0 0 0 0 0
   0 0 0 1 0 0 0 0 0 0 0 0 0 0
   0 0 0 0 1 0 0 0 0 0 0 0 0 0
   0 0 0 0 0 1 0 0 0 0 0 0 0 0
   0 0 0 0 0 0 1 0 0 0 0 0 0 0];
D=0;

ChaChing

help freqresp, bode
& ref

Frequency Domain Analysis
allmargin        All crossover frequencies and corresponding stability margins
bode        Bode diagram of frequency response
bodemag        Bode magnitude response of LTI models
db2mag        Convert decibels (dB) to magnitude
evalfr        Evaluate frequency response at given frequency
freqresp        Frequency response over frequency grid
mag2db        Convert magnitude to decibels (dB)
margin        Gain and phase margins and associated crossover frequencies
nichols        Nichols plot of LTI models
nyquist        Nyquist plot of LTI models
sigma        Plot singular values of LTI models