MATLAB and C Programs - Digital Signal Processing: A Practitioner's Approach - page 136

q=angle(roots(a));
theta1(i)=q(1);
end
imax=20;jmax=8;
delt=linspace(0.05,0.9,imax);
Ts1=1/(0.5*f) ;Ts2=1/(100*f);
Ts3=linspace(Ts2,Ts1,jmax);
Ts0=linspace(Ts3(1),Ts3(3),jmax);
Ts0(jmax+1:2*jmax-3)=Ts3(4:jmax);
jmax=length(Ts0);
for j=1:jmax
Ts=Ts0(j);
k=1;
for i=1:imax
delta=delt(i);
f=100;
omega=2*pi*f;
b1=omega*omega;
a1=[1 2*delta*omega omega*omega];
sysc=tf(b1,a1);
sysd=c2d(sysc,Ts,'tustin');
[b a]=tfdata(sysd,'v');
q1=abs(roots(a));
g2(i)=b(1);
r2(k)=q1(1);
q2=angle(roots(a));
theta2(k)=q2(1);
k=k+1;r2(k)=q1(2);theta2(k)=q2(2);k=k+1;
end
%p=polyfit(delt,r2,1);
%r2hat=p(1)*delt+p(2);
%m(j)=p(1); c(j)=p(2);
Tss(j)=Ts;
A(j,:)=delt;B(j,:)=r2;C(j,:)=theta2;
%subplot(211) ;plot(delt,r2, 'o', delt,r2hat) ;grid
%subplot (212) ;plot (delt, theta2* (180/pi), ' o') ;grid
%polar (theta2,r2, ' o');grid
%theta(j)=mean(theta2*(180/pi));
%Ts
end
subplot(111);polar(C,B,'o');grid;
%[xp,yp]=ginput(1);text(xp,yp,' Fig 2.7 ');
%[xp,yp]=ginput(1) ;text(xp,yp,'

< --- Constant Sampling Rate ');
%[xp,yp]=ginput(1) ;text(xp,yp,' Sensivity of System ');