n=1:1:16;
x=[3100101189000000];
subplot（321）;
stem（nx）;
title（‘輸入序列‘）

if?length（x）<16
????x1=[xzeros（116-length（x））];
end
if?length（x）==16
????x1=x;
end
a=-j*2*pi/4;
b=-j*2*pi/16;

for?n0=0:1:3
????for?k0=0:1:3
????????for?n1=0:1:3
????????x2（4*k0+n0+1）=x1（4*n1+n0+1）*exp（a*n1*k0）+x2（4*k0+n0+1）;
????????end
????end
end
for?k0=0:1:3
????for?n0=0:1:3
????????x3（4*k0+n0+1）=x2（4*k0+n0+1）*exp（b*n0*k0）;
????end
end