This paper considers the performance of a communication system which transmits for

seconds the real part of a sample function of one of

stationary complex Gaussian processes whose spectral densities are all frequency translations of the function

. At the receiver white Gaussian noise of one-sided density

is added. The center frequencies of the processes are assumed to be sufficiently separated that the

covariance functions are orthogonal over

. Exponently tight bounds are obtained for the error probability of the maximum likelihood receiver. It is shown that the error probability approaches zero exponentially with

for all rates

up to
![C = \\int_{-\\infty }^{\\infty } [S_{\\xi} (f)/N_{0}] df - \\int_{-\\infty }^{\\infty } \\hbox{ ln } [1 + S_{\\xi}(f)/N_{0}] df](/images/tex/6852.gif)
which is shown to be the channel capacity. Similar results are obtained for the case of stochastic signals with specular components.