Assume that we are using recursive least squares to estimate a transfer function
$$A(q)y(t) = B(q)u(t)$$
But the input $u(t)$ is delayed with $d$ time, eg: $$A(q)y(t) = B(q)u(t-d)$$
How can I find the $d$ value if I have $y(t), u(t)$ saved in a list?