[′krȯs kär·ə′lā·shən ‚fəŋk·shən] (communications) A function, φ12(τ), where τ is a time-delay parameter, equal to the limit, as T approaches infinity, of the reciprocal of 2 T times the integral over t from -T to T of f1(t) f2(t - τ), where f1 and f2 are functions of time, such as the input and output of a communication system.AcronymsSeeCCF