autocorrelation(x)

function [resultat] = autocorrelation(x)
% fonction dautocorrelation pour une seule fen^etre
s = size(x);
N = s(2);
x1 = x;
x1(1,N+1:2*N-1) = zeros(1,N-1);
x2 = zeros(N-1, 2*N-1);
for i = 1:N-1
x2(i,i:i+N-1) = x;
end;
resultat = 1/N*x1*x2';