A MULTISTAGE NONLINEAR ECHO-CANCELLER FOR DIGITAL COMMUNICATION SYSTEMS WITH OR WITHOUT FREQUENCY DIVISION DUPLEXING

摘要

In a digital communication system where digitally modulated signals are transmitted in a signal path including a bi­directional channel (218), a multistage echocanceller (207) has two or more stages connected in a sequence to remove the linear and nonlinear echo of the outgoing signal from the incoming signal (220). Results are of importance both to systems overlapping outgoing and incoming frequency bands and to those with separated bands (for which only the nonlinear echo is of concern). The two or more stages are each characterized by a respective function, and the sequence is characterized by alternation of the functions of the two or more stages between linear and nonlinear.