Improved Circuit of Digital Phone line duplex telephone subscriber line interface between an analog and a digital switching system

摘要

A digital telecommunication line circuit implementable on one or more large scale integrated circuit (LSI) chips is described. A simplified integrated hardware structure is provided so as to achieve the combination on an LSI chip of an electronic two-to-four wire hybrid, line impedance matching by automatic digital impedance synthesizing of an output impedance and all digital filtering functions for an all LSI telephone line circuit including automatic equalizing.