On the implementation of adaptive electronic hybrid for digital subscriber loops

An adaptive electronic hybrid is proposed to replace the conventional fixed hybrid in a digital subscriber loop and thus reduce the burden on the echo canceller. The theory of the adaptive hybrid is briefly reviewed. A simple method of hardware implementation is described in which the poles of the echo path transfer function are assumed to be constant. A three-residue adaptive electronic hybrid is realized by linear integrated circuits and shown experimentally to achieve at least 26-dB transhybrid loss