fig134.m

realize analysis and design for computer-controlled system

% Generates Fig 13.4 (recurex)
% Using the System Identification Toolbox
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-08-04
% 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 10])
set(gcf,'Units','centimeters','position',get(gcf,'PaperPosition'))

lw=0.9;

N=500;
a1=-0.8;
b1=0.5;
sig=0.5;

model=poly2th([1 a1],[0 b1]);
u=idinput(600,'prbs',[0 1/5]);
u=-u(1:N);
randn('seed',0);
e=sig*randn(N,1);
y=idsim([u e],model);
subplot(3,1,1)
plot(y,'k-','Linew',lw);
axis([0,N,-7 7]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 N],'ytick',[-5 0 5]);
ylabel('Output','Fontsize',9,'Fontname','NewCenturySchlbk')
%[ts,ys]=stairs(t,y(:,2));
subplot(3,1,2)
t=1:N;
[ts,us]=stairs(t,u);
plot(ts,us,'k-','Linew',lw);
axis([0,N,-1.2  1.2]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0 N],'ytick',[-1 0 1]);
ylabel('Input','Fontsize',9,'Fontname','NewCenturySchlbk')
xlabel('Time','Fontsize',9,'Fontname','NewCenturySchlbk')
%
drawnow;
ylblalgn;