fig67.m

realize analysis and design for computer-controlled system

% Generates Fig 6.7
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-04
% Copyright (c) 1996 by K. J. 舠tr鰉, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

newplot;
set(gcf,'PaperUnits','centimeters','PaperPosition',[2 2 13 8])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))

lw=0.9;
x1=-10:0.05:10;
s1=2;
m1=s1;
s2=0.75;
m2=s2;
g1=1/(s1*sqrt(2*pi))*exp(-(x1-ones(size(x1))*m1).*(x1-ones(size(x1))*m1)/(s1*s1));
g2=1/(s2*sqrt(2*pi))*exp(-(x1-ones(size(x1))*m2).*(x1-ones(size(x1))*m2)/(s2*s2));
clf
plot(x1,g1,'k--',x1,g2,'r-','Linewi',lw)
hold on
set(gca,'Fontname','newcent','Fontsize',9)
set(gca,'xtick',[-2 0 2 4 6],'ytick',[0 0.5])
plot([0 0],[0 1],'k:','Linewi',lw)
plot([m1 m1],[0 0.25],'k:','Linewi',lw)
plot([m2 m2],[0 0.58],'k:','Linewi',lw)
axis([-3 7 0 0.6]);
xlabel('Process output','Fontname','newcent','Fontsize',9)
ylabel('Probability density','Fontname','newcent','Fontsize',9)
text(1.0,0.57,'Set point for regulator','Fontname','newcent','Fontsize',9)
text(1.0,0.54,'with low variance','Fontname','newcent','Fontsize',9)
text(2.2,0.25,'Set point for regulator','Fontname','newcent','Fontsize',9)
text(2.2,0.22,'with high variance','Fontname','newcent','Fontsize',9)
text(-1.85,0.4,'Test limit','Fontname','newcent','Fontsize',9)