x = randn(1,1000);
c = [1 0 .5 -.3];
d = filter(c,1,x);
L = 10;
w = zeros(L,1);
mu = 0.01;


for n = L:1000,
    Xtdl = x(n:-1:n-L+1)';
    y(n) = w'*Xtdl;
    e(n) = d(n)-y(n);
    w = w + 2*mu*e(n)*Xtdl;
 end;