Cross-correlation techniques and their application to communication channel evaluation

Cross-correlation methods for determining the time domain response of systems are finding increasing use in the communications field. This paper discusses the adapting of these techniques to communication channel testing. Present-day solid-state devices enable compactand economical test equipment to be constructed. The immunity of the method to noise and interference suggest that `on-line¿ testing in the presence of normal traffic might be possible. Results of a computer simulation seem to confirm that `on-line¿ testing is indeed feasible, and that low-level test sequences may be used to obtain channel response information with sufficient accuracy to operate automatic time domain channel model synthesizers or equalizers.