Digital computing device for a data transmission installation using code 2B 1Q or the like

摘要

A device for real time computing of a sum of terms having the form SIGMA h(iT).qe((n-i)T) is suitable for use in an echo canceller for a data transmission system using code 2B 1Q. The device first transforms each of the successive estimated values of qe into transformed values qde which are powers of two, by adding or subtracting 1. The successive elementary products each obtained by a shift of h by an amount selected in response to the respective value of qde. The elementary products are summed in a register.