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1. (WO1998053595) METHOD AND DEVICE FOR REDUCING MULTI-CHANNEL ACOUSTIC ECHO AND ADAPTING SOUND TO SPACE CONDITIONS
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1998/053595 International Application No.: PCT/FR1998/001010
Publication Date: 26.11.1998 International Filing Date: 20.05.1998
Chapter 2 Demand Filed: 09.12.1998
IPC:
H04M 9/08 (2006.01)
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
M
TELEPHONIC COMMUNICATION
9
Arrangements for interconnection not involving centralised switching
08
Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
Applicants:
FRANCE TELECOM [FR/FR]; 6, place d'Alleray F-75015 Paris, FR (AllExceptUS)
THOMAS, Jean-Philippe [FR/FR]; FR (UsOnly)
SALIOU, Alain [FR/FR]; FR (UsOnly)
EMERIT, Marc [FR/FR]; FR (UsOnly)
MAHIEUX, Yannick [FR/FR]; FR (UsOnly)
Inventors:
THOMAS, Jean-Philippe; FR
SALIOU, Alain; FR
EMERIT, Marc; FR
MAHIEUX, Yannick; FR
Agent:
LOISEL, Bertrand ; Cabinet Plasseraud 84, rue d'Amsterdam F-75440 Paris Cedex 09, FR
Priority Data:
97/0619121.05.1997FR
Title (EN) METHOD AND DEVICE FOR REDUCING MULTI-CHANNEL ACOUSTIC ECHO AND ADAPTING SOUND TO SPACE CONDITIONS
(FR) PROCEDE ET DISPOSITIF DE REDUCTION D'ECHO ACOUSTIQUE MULTIVOIES ET DE SPATIALISATION SONORE
Abstract:
(EN) In order to reduce acoustic echo and restore stereophonic sound in a digital transmission system of sound signals on P transmission channels, between a local site and one or several remote site(s), comprising several microphones and loudspeakers, the method consists in the following steps: computing a weighting factor ($g(b)i)(n) to be applied to each microphone signal xi(n) before emitting, based on two attenuation factors G'mic(i,n) and $g(G)'(i,n) computed from the microphone and loudspeaker signals; transmitting on each transmission channel the linear combination (I) of weighted microphone signals, in which N is the number of microphones and $g(a)k,i(n) represents real coding coefficients; then computing a weighting factor $g(l)j(n) to be applied to each loudspeaker signal zj(n); emitting on the jth loudspeaker the linear combination (II) of transmitted weighted yk(n) signals, in which $g(g)j,k(n) represents real decoding coefficients.
(FR) Pour réduire l'écho acoustique et restituer le relief sonore dans un système de transmission numérique de signaux sonores sur P canaux de transmission, entre un site local et un ou plusieurs site(s) distant(s), comportant chacun plusieurs microphones et haut-parleurs, on calcule un coefficient de pondération $g(b)i(n) à appliquer à chaque signal microphonique xi(n) avant émission, à partir de deux atténuations G''mic(i,n) et $g(G)'(i,n) calculées à partir des signaux microphoniques et de haut-parleurs; on transmet sur chaque canal de transmission la combinaison linéaire (I) des signaux microphoniques pondérés, où N est le nombre de microphones et $g(a)k,i(n) désigne des coefficients de codage réels; puis on calcule un coefficient de pondération $g(l)j(n) à appliquer à chaque signal de haut-parleur zj(n); et on émet sur le jème haut-parleur la combinaison linéaire (II) des signaux transmis yk(n) pondérés, où $g(g)j,k(n) désigne des coefficients de décodage réels.
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Designated States: JP, US
European Patent Office (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
Publication Language: French (FR)
Filing Language: French (FR)
Also published as:
EP0983678US6424720JP2001526860