www.pudn.com > voiceprocessingtoolbox.rar > convolution01.m

% Plot an unit impulse signal 
 
n = -7:7; 
x = [0 0 0 0 0 0 0 1 2 3 0 0 0 0 0]; 
 
subplot(4,2,1); 
stem(n, x); 
limit=[min(n), max(n), 0, 5]; 
axis(limit); 
title('Input x[n]'); 
 
subplot(4,2,3); 
x0=0*x; 
x0(8)=x(8); 
stem(n, x0); 
axis(limit); 
h=text(0, x0(8), 'x[0]'); set(h, 'horiz', 'center', 'vertical', 'bottom'); 
 
subplot(4,2,4); 
y0=0*x; 
index=find(x0); 
for i=index:length(n) 
	y0(i)=x0(index)*exp(-(i-index)/2); 
end 
stem(n, y0); 
axis(limit); 
h=text(0, x0(8), 'x[0]*h[n-0]'); set(h, 'vertical', 'bottom'); 
 
subplot(4,2,5); 
x1=0*x; 
x1(9)=x(9); 
stem(n, x1); 
axis(limit); 
h=text(1, x1(9), 'x[1]'); set(h, 'horiz', 'center', 'vertical', 'bottom'); 
 
subplot(4,2,6); 
y1=0*x; 
index=find(x1); 
for i=index:length(n) 
	y1(i)=x1(index)*exp(-(i-index)/2); 
end 
stem(n, y1); 
axis(limit); 
h=text(1, x1(9), 'x[1]*h[n-1]'); set(h, 'vertical', 'bottom'); 
 
subplot(4,2,7); 
x2=0*x; 
x2(10)=x(10); 
stem(n, x2); 
axis(limit); 
h=text(2, x2(10), 'x[2]'); set(h, 'horiz', 'center', 'vertical', 'bottom'); 
 
subplot(4,2,8); 
y2=0*x; 
index=find(x2); 
for i=index:length(n) 
	y2(i)=x2(index)*exp(-(i-index)/2); 
end 
stem(n, y2); 
axis(limit); 
h=text(2, x2(10), 'x[2]*h[n-2]'); set(h, 'vertical', 'bottom'); 
 
subplot(4,2,2); 
stem(n, y0+y1+y2); 
axis(limit); 
title('Output y[n] = x[0]*h[n-0] + x[1]*h[n-1] + x[2]*h[n-2]');