Correlation of signal fluctuations at two frequencies in propagation through an irregular medium

The Rytov method of calculating the signal fluctuations produced in wave propagation through a medium containing weak random irregularities in refractive index is used to study the correlation between the fluctuations occurring at different frequencies over the same line-of-sight transmission path. Amplitude and phase fluctuations are treated separately, and explicit results are given for three different types of irregularity spectrum function.