ex020500.m

matlab写的数字信号处理源代码,里面包括最基本的fft计算

% Example 2.5
%
% x(n)=[u(n)=u(n-10]; h(n)=(0.9)^n*u(n)
% y(n)=10*(1-(0.9)^(n+1))*(u(n)-u(n-10))+
%       (10*(1-(0.9)^10)*(0.9)^(n-9))*u(n-10)
n = -5:50;
u1 = stepseq(0,-5,50); u2=stepseq(10,-5,50);
% input x(n)
x = u1-u2;
% impulse response h(n)
h = ((0.9).^n).*u1;
subplot(1,1,1)
subplot(2,1,1); stem(n,x); axis([-5,50,0,2])
title('Input Sequence')
xlabel('n'), ylabel('x(n)')
subplot(2,1,2); stem(n,h); axis([-5,50,0,2])
title('Impulse Response')
xlabel('n'), ylabel('h(n)'); pause
%print -deps2 ex0205a.eps
% output response
y = (10*(1-(0.9).^(n+1))).*(u1-u2)+(10*(1-(0.9)^10)*(0.9).^(n-9)).*u2;
subplot(1,1,1)
subplot(2,1,2); stem(n,y); axis([-5,50,0,8])
title('Output Sequence')
xlabel('n'), ylabel('y(n)')
%print -deps2 ex0205b.eps