DIGITAL SUBSCRIBER LOOP TRANSMISSION USING ECHO CANCELLER AND BALANCING NETWORKS.

A description is given of a 144-kb/s subscriber loop transmission system based on a hybrid transmission technology. The automatically controlled balancing network to obtain a high return loss, the 2-stage structure of an echo canceller to reduce the precision of D/A converter, and the specially formatted packetized data frame to realize a stable timing extraction characterize the system. A total system, which also has a ROOT f AGC equalizer and a decision-feedback equalizers, was implemented. An experiment showed error-8free transmission on a 4-km cable with a 0. 4-mm diameter.