echo on
q=2; n=500;
sigma2=2.25; sigma=sqrt(sigma2);
PHI = []; THETA = -[0.5,0.2];
[x,phir,thetar]=armagen(PHI,THETA,n,sigma);
thetar
[xro,xroE,mi,miE,xacf]=acf(x,figure);
xs=conv(x,[0;phi]); xs=xs(1:n);
length(xs)
% figure; plot(1:n,x,'w',1:n,xs,'y--');
echo off