Let

be the Wiener filter designed to yield an output which is the least-square approximation to

where

is the desired signal input. Let

be the Wiener filter designed to yield an output which is the least-square approximation to some linear operation

on the desired input signal. The following simple relationship has been shown to hold between

and

. If

is the desired input signal and

is the desired output, where

is some linear operation with respect to

, then
![Y_L(\\omega ) = L_{\\alpha }[Y(\\omega , \\alpha )]](/images/tex/4705.gif)
.