Abstract: Under the criteria of Wiener's least mean square error, the optimum solution of frequency-domain is given. If we consider the Widrow's tapped daley line as a transversal 'filter, it can approximate the optimum transfer function with required accurancy.
Under certain conditions, the optimum weight cofficients of time-domain just equal the coefficients of Fourier expansion of optimum transfer function.
two different proofs for those are given.
In the-end, some practical examples applying the results to be described in this paper are shown.