It is known that the entropy
distance between two Gaussian measures is finite if, and only if, they are absolutely
continuous with respect to one another. Shepp (1966) characterized the correlations
corresponding to stationary Gaussian measures that are absolutely continuous with
respect to the Wiener measure. By analyzing the entropy distance, we show that one
of his conditions, involving the spectrum of an associated operator, is essentially
extraneous, providing a simple criterion for finite entropy distance in this
case.