Asymptotic normality of the sample convariances of evanescent fields in noise

We consider the asymptotic properties of the sample covariance sequence of a field composed of the sum of evanescent components and a purely-indeterministic component. In this framework a Bartlett-type formula for the covariance function of the sample covariances of a horizontal evanescent field observed in the presence of a purely-indeterministic field, is derived. The asymptotic normality of the sample covariances is established