fg_04_04.m

英文书《Digital Signal Processing with Examples in MATLAB》附带的MATLAB实例

% stearns_04_04
% Chapter 4, fig. 4.4. z-plane & phase plots.
% z-plane plot
b=[1,1]; a=[1,-.9];
sp_fig(1,10,5);
subplot(1,2,1);
pz_plot(b,a);
ejw=exp(j*pi/3);
arrow(-1,0,real(ejw),imag(ejw));
arrow(.9,0,real(ejw),imag(ejw));
h1=text(-.75,.08,'\theta');
h2=text(.87,.18,'\phi');
h3=text(.54,.95,'e^{j\omegaT}','rotation',0);
h4=text(real(ejw)-.03,imag(ejw)+.01,'\bullet');
set([h1,h2,h3,h4],'Fontname','times','fontsize',16);
% Phase plot
f=linspace(0,.5,200);
phase=unwrap(angle(gain_f(b,a,f)));
axes('position',[.6 .2 .3 .6]);
axis([0,.5,-100,0]);
set(gca,'Fontname','times','fontsize',16);
line(f,phase*180/pi,'color','k'); grid;
xlabel('Frequency {\nu}=\omegaT/2\pi (Hz-s)');
ylabel('Angle[{\itH}(e^{j\omega})]=\theta-\phi (deg.)');