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Process to Choose Between Echo Cancellation and Echo Suppression

IP.com Disclosure Number: IPCOM000040554D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02

Publishing Venue

IBM

Related People

Authors:
Roulier, G [+details]

Abstract

In voice transmission networks, the transmission path includes bidirectional lines (2 wires) combined with unidirectional lines (4 wires), with conversion from 2 to 4 wires, and conversely, achieved through the use of hybrid transformers. In practice, imperfect balancing of the hybrid transformers is the source of feedback noise (echoes) from one unidirectional line to another. Two solutions are usually available, i.e., echo suppressors that simply turn one unidirection communication way off and echo cancellers. Echo cancellers are usually used to cancel the echoes by generating an echo replica and then subtracting the replica from the echo- spoiled signal.