We describe how the coherence function—a Fourier frequency–dependent measure of the linear correlation between time series measured simultaneously in two energy channels—can be used in conjunction with energy spectra, power spectra, and time delays between energy channels to constrain models of the spectrum and variability of X-ray binaries. Here we present a procedure for estimating the cohere...

We describe how the coherence function—a Fourier frequency-dependent measure of the linear correlation between time series measured simultaneously in two energy channels—can be used in conjunction with energy spectra, power spectra, and time delays between energy channels to constrain models of the spectrum and variability of X-ray binaries. Here we present a procedure for estimating the cohere...