fg_07_01.m

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

% fg_07_01  Nonstationary and stationary waveforms.
N=40; r=.99; s=round(.1*N/2);
Nx=1000; k=0:Nx-1;
randn('state',0);
x=randn(1,Nx);

y=comb(N,s,r,x);
sp_fig(1,9,5.5);
subplot(3,1,1);
axis([0 Nx -1 1]); grid on;
set(gca,'fontsize',16);
set(gca,'xticklabel',[]);
u=.2*(linspace(1,10,Nx).*y+.5*x);
line(0:Nx-1,u,'color','r');
ylabel('x_k');
text(390,1.2,'Nonstationary','fontsize',16);

subplot(3,1,2);
axis([0 Nx -1 1]); grid on;
set(gca,'fontsize',16);
set(gca,'xticklabel',[]);
u=.2*(2*sin(2*pi*k.*(.01+(k/Nx)*.04))+x);
line(0:Nx-1,u,'color','r');
ylabel('x_k');
text(390,1.2,'Nonstationary','fontsize',16);

subplot(3,1,3);
axis([0 Nx -1 1]); grid on;
set(gca,'fontsize',16);
u=0.3*(5*y+.5*x);
line(0:Nx-1,u,'color','b');
xlabel('k'); ylabel('x_k');
text(410,1.2,'Stationary','fontsize',16);