fig106.m

realize analysis and design for computer-controlled system

% Generates Fig 10.6
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-10
% Copyright (c) 1996 by K. J. 舠tr鰉, B. Wittenmark and
% Department of Automatic Control, Lund Institute of
% Technology, Lund, Sweden

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

lw=0.9;
den=[1 -3 4.5 -3 1];
num=0.25*[1 2.5 1 0]/(2*pi);
pol=roots(den);
zer=roots(num);
a=real(poly([pol(3),pol(4)]));
b=sqrt(num(1))*poly(zer(2));
w=linspace(-pi,pi);
%w=logspace(-3,pi,100);
[mag,ph,w]=dbode(num,den,1,w);
subplot(2,1,1)
plot(w,mag,'k','Linew',lw)
axis([-4 4 0 0.75])
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[-4 -2 0 2 4]);
set(gca,'ytick',[0 0.5]);
xlabel('Frequency','Fontname','NewCenturySchlbk','Fontsize',9)
ylabel('Magnitude','Fontname','NewCenturySchlbk','Fontsize',9)