fig712.m

realize analysis and design for computer-controlled system

% Generates Bodediagram of 6th order Bessel filter and timedelay
% Generates Fig 7.12
% Computer Controlled Systems (3rd ed)
% Author: B. Wittenmark
% Last edit: 1997-07-05
% 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;
z1=0.49;
om1=1.90;
z2=0.82;
om2=1.69;
z3=0.98;
om3=1.61;
b=om1*om1*om2*om2*om3*om3;
a=conv([1 2*z1*om1 om1*om1],[1 2*z2*om2 om2*om2]);
a=conv(a,[1 2*z3*om3 om3*om3]);
clf;
hold on
w1=logspace(-1,1);
[mag1,ph1,w1]=bode(b,a,w1);
ph2=-w1*2.7*360/(2*pi);
subplot(2,1,1)
loglog(w1,mag1,'m-','Linew',lw)
axis([0.1 10 0.001 2])
hold on
plot([0.1 10],[1 1],'k--','Linew',lw)
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'ytick',[0.01 1]);
set(gca,'xtick',[0.1 1 10]);
ylabel('Gain','Fontname','NewCenturySchlbk','Fontsize',9)

subplot(2,1,2);
semilogx(w1,ph1,'m-',w1,ph2,'k--','Linew',lw)
hold on
axis([0.1,10,-500,0]);
set(gca,'Fontsize',9,'Fontname','NewCenturySchlbk');
set(gca,'xtick',[0.1 1 10]);
set(gca,'ytick',[-360 -180 0]);
xlabel('Frequency, rad/s','Fontname','NewCenturySchlbk','Fontsize',9)
ylabel('Phase','Fontname','NewCenturySchlbk','Fontsize',9)
%fr2=frc(1,1,2.7,-1,1);
%scale=[-1 1 -3 0 -500 0];
%bopl(fr1,fr2,scale);
drawnow;
ylblalgn;