Comments on "A derivation of the normal equation in FIR Wiener filters" by Y.-D. Huang and C.-T. Chen

The proof of the normal equation for the finite impulse response (FIR) Wiener filter in the complex case given in the above-mentioned correspondence (see ibid., vol.37, no.5, p.759, 1989) is analyzed. It is shown that a much simpler and comprehensive proof can be given by inserting the problem in its natural geometrical framework of minimization of a distance.<
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