fig84.m

realize analysis and design for computer-controlled system

% Generates Fig 8.4
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-09
% 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 10])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))
clear
lw=0.9;

apol=conv([1 10 25],conv([1 2 100],[1 3 2500]));
bpol=conv([1 2 2],[1 2 400]);
wrad=logspace(0,3,200);
[mag,ph,wrad]=bode(bpol,apol,wrad);

h=0.03;
[bdpol,adpol] = c2dm(bpol,apol,h,'zoh');
[mag1,ph1,wrad1]=dbode(bdpol,adpol,h);
[bdpol,adpol] = c2dm(bpol,apol,h,'tustin');
[mag2,ph2,wrad2]=dbode(bdpol,adpol,h);
[bdpol,adpol] = c2dm(bpol,apol,h,'first');
[mag3,ph3,wrad3]=dbode(bdpol,adpol,h);

subplot(2,1,1)
loglog(wrad,mag,'m-',wrad1,mag1,'k--',wrad2,mag2,'k:',wrad3,mag3,'k-.','Linew',lw)
axis([1 200 0.00001 0.01])
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
ylabel('Magnitude','Fontname','NewCenturySchlbk','Fontsize',9)
hold on
%title('Fig 8.4 cont(-), zoh(--), tustin(:), first(-.)')

subplot(2,1,2)
semilogx(wrad,ph,'m-',wrad1,ph1,'k--',wrad2,ph2,'k:',wrad3,ph3,'k-.','Linew',lw)
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
axis([1 200 -300 100]);
set(gca,'ytick',[-200 0]);
xlabel('Frequency, rad/s','Fontname','NewCenturySchlbk','Fontsize',9)
ylabel('Phase','Fontname','NewCenturySchlbk','Fontsize',9)
hold on

ylblalgn;