fig59.m

realize analysis and design for computer-controlled system

% Generates Fig 5.9
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-02
% Copyright (c) 1996 by K. J. 舠tr鰉, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

newplot;clf;
lw=0.9;
set(gcf,'PaperUnits','centimeters','PaperPosition',[2 2 13 9.5])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))

A=[1 -1];
B=[0.1];
R=[1 -1];
AR=conv(A,R);
BR=conv(B,R);
wrad1=logspace(-3,pi,100);

al=0.99;
S=[12-10*al 8*al-10];
BS=conv(B,S);
Ac=AR+[0 BS];
[mag1,ph1,wrad1]=dbode(BR,Ac,1,wrad1);
subplot(2,2,1);
loglog(wrad1,mag1,'k-','Linew',lw)
axis([0.01 10 0.02 2])
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'ytick',[0.1 1]);
set(gca,'xtick',[0.01 0.1 1 10]);
ylabel('Gain','Fontname','NewCenturySchlbk','Fontsize',9)
xlabel('Frequency, rad/s','Fontname','NewCenturySchlbk','Fontsize',9)
hold on
plot([0.01 10],[1 1],'k:','Linew',lw)
text(0.001,2,'(a)','Fontname','NewCenturySchlbk','Fontsize',9)

[mag1,ph1,wrad1]=dbode(BS,Ac,1,wrad1);
subplot(2,2,2);
loglog(wrad1,mag1,'k-','Linew',lw)
axis([0.01 10 0.02 2])
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'ytick',[0.1 1]);
set(gca,'xtick',[0.01 0.1 1 10]);
ylabel('Gain','Fontname','NewCenturySchlbk','Fontsize',9)
xlabel('Frequency, rad/s','Fontname','NewCenturySchlbk','Fontsize',9)
hold on
plot([0.01 10],[1 1],'k:','Linew',lw)
text(0.001,2,'(b)','Fontname','NewCenturySchlbk','Fontsize',9)

al=0.9;
S=[12-10*al 8*al-10];
BS=conv(B,S);
Ac=AR+[0 BS];
[mag1,ph1,wrad1]=dbode(BR,Ac,1,wrad1);
subplot(2,2,1);
loglog(wrad1,mag1,'k--','Linew',lw)

[mag1,ph1,wrad1]=dbode(BS,Ac,1,wrad1);
subplot(2,2,2);
loglog(wrad1,mag1,'k--','Linew',lw)

al=0.5;
S=[12-10*al 8*al-10];
BS=conv(B,S);
Ac=AR+[0 BS];
[mag1,ph1,wrad1]=dbode(BR,Ac,1,wrad1);
subplot(2,2,1);
loglog(wrad1,mag1,'k-.','Linew',lw)

[mag1,ph1,wrad1]=dbode(BS,Ac,1,wrad1);
subplot(2,2,2);
loglog(wrad1,mag1,'k-.','Linew',lw)

al=0;
S=[12-10*al 8*al-10];
BS=conv(B,S);
Ac=AR+[0 BS];
[mag1,ph1,wrad1]=dbode(BR,Ac,1,wrad1);
subplot(2,2,1);
loglog(wrad1,mag1,'k:','Linew',lw)

[mag1,ph1,wrad1]=dbode(BS,Ac,1,wrad1);
subplot(2,2,2);
loglog(wrad1,mag1,'k:','Linew',lw)