Translations:Dictionary:Crosscorrelation theorem/3/en

where $G_{1}(f),G_{2}(f),\Phi _{12}(f)$ are the Fourier transforms of $g_{1}(t),g_{2}(t),\phi _{12}(\tau )$, and the superscribed bar indicates a complex conjugate. Here $\Phi _{12}(f)$ is called the cross-energy spectrum. See Figure F-22 and Sheriff and Geldart (1995, 285, 538, and 541-542) .