INTERFACE CIRCUIT BETWEEN A FOUR WIRE LINE AND A TWO WIRE LINE

摘要

. An interface circuit between a four wire line and a two wire line includes correlator and control circuit means (32,34,36) connected for receiving a longitudinal signal (V1) and a transversal signal (Vt) corresponding to a differential signal received on the terminals of a two wire interface from the two wire line. The correlator and control circuit means include circuit means (32) for creating a correction signal (33) being a measure of the correlation between the longitudinal signal and the transversal signal. The circuit means for creating the correction signal are connected for using this correction signal to adaptively control the amplifications in feed back loops (26,14,18; 28,16,20) so as to minimize the correlation between the longitudinal and transversal signals.