ch4_5.m

《MATLAB7.0控制系统应用实例》 作者：刘叔军

A=[1 -0.5 0.7];B=[0 1 0.5];
th0=poly2th(A,B);
u=idinput(300, 'rbs');
y=idsim([u,randn(300,1)],th0);
m=[y u];
Mi = [2 2 3 1 1 2  ]; 
ma = pem(m,Mi);
[e,r] = resid(m,ma);	
resid(r)
% w = logspace(-2,pi,128);
% g= spa(z,[],w); % (empty matrix gives default)
% bode(g,'sd',3)
% figure, bode(g('noise'),'sd',3) % The noise spectrum with confidence interval of 3 standard deviations.