fg_10_20.m

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

% fg_10_20       Decimation & Expansion Spectra
t=0:199; N=800; p=14;
n=0:N-1;
z=zeros(1,N/4);
x1=1.2*t.*exp(-t/20);
x2=[linspace(0,2,40) linspace(2,0,160)];
sp_fig(1);

subplot(3,2,3);
line(2*[0:N/2-1],[x1 rev(x1)],'color','k'); grid on;
set(gca,'xticklabel',' ');
set(gca,'yticklabel','0||0.5','fontname','times','fontsize',p);
dx3=[10 70 50 80 70];
x3=get(gca,'xtick')-dx3;
xlab3=char('0','\pi/2T_2','\pi/T_2','3\pi/2T_2','2\pi/T_2');
y3=-1.5*(ones(1,5));
text(x3,y3,xlab3,'fontname','times','fontsize',p);
ylabel('U^{1D}(\omega)','fontname','times','fontsize',p);

subplot(3,2,4);
line(n,[x1 rev(x1) x1 rev(x1)],'color','k'); grid on;
set(gca,'xticklabel',' ');
set(gca,'yticklabel','0||0.5','fontname','times','fontsize',p);
dx2=[10 50 40 70 60];
a2=get(gca,'xtick')-dx2;
b2=-1*(ones(1,5));
xlab2=char('0','\pi/2T','\pi/T','3\pi/2T','2\pi/T');
text(a2,b2,xlab2,'fontname','times','fontsize',p);
ylabel('U^{1E}(\omega)','fontname','times','fontsize',p);

subplot(3,2,5);
line(2*[0:N/2-1],[x2 rev(x2)],'color','k'); grid on;
set(gca,'xticklabel',' ');
set(gca,'yticklabel','0||0.5','fontname','times','fontsize',p);
text(x3,y3,xlab3,'fontname','times','fontsize',p);
ylabel('U^{2D}(\omega)','fontname','times','fontsize',p);
axis([0 800 0 10]);
xlabel('\omega (rad/s)','fontname','times','fontsize',p);

subplot(3,2,6);
line(n,[x2 rev(x2) x2 rev(x2)],'color','k'); grid on;
set(gca,'xticklabel',' ');
set(gca,'yticklabel','0||0.5','fontname','times','fontsize',p);
text(a2,b2,xlab2,'fontname','times','fontsize',p);
ylabel('U^{2E}(\omega)','fontname','times','fontsize',p);
axis([0 800 0 10]);
xlabel('\omega (rad/s)','fontname','times','fontsize',p);