[go: up one dir, main page]

SE8205839L - echo canceller - Google Patents

echo canceller

Info

Publication number
SE8205839L
SE8205839L SE8205839A SE8205839A SE8205839L SE 8205839 L SE8205839 L SE 8205839L SE 8205839 A SE8205839 A SE 8205839A SE 8205839 A SE8205839 A SE 8205839A SE 8205839 L SE8205839 L SE 8205839L
Authority
SE
Sweden
Prior art keywords
echo
signal
echo canceller
canceller
stage
Prior art date
Application number
SE8205839A
Other languages
Unknown language ( )
Swedish (sv)
Other versions
SE8205839D0 (en
Inventor
D A Alsberg
R P Coulter
T H Curtis
G-S Fang
Original Assignee
Western Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Western Electric Co filed Critical Western Electric Co
Publication of SE8205839D0 publication Critical patent/SE8205839D0/en
Publication of SE8205839L publication Critical patent/SE8205839L/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers
    • H04B3/237—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers using two adaptive filters, e.g. for near end and for end echo cancelling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers
    • H04B3/234—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers using double talk detection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
    • H04B3/23—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers
    • H04B3/238—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other using a replica of transmitted signal in the time domain, e.g. echo cancellers using initial training sequence

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Noise Elimination (AREA)

Abstract

The invention is a two-stage echo canceller arrangement including a first echo cancelling stage (20) and a second echo cancelling stage (18). The first a. echo canceller adapts an input signal (x(k)) to synthesize a first estimate of an echo replica signal (@1(k)). A combiner (28) subtracts this first echo replica signal from the actual echo signal to generate a first echo cancelled signal (e1(k)). A control unit (30) monitors the change in value of the echo cancelled signal, and locks the adaptation process of the first echo canceller when the first echo cancelled signal is sufficiently less than the input signal, usually 6 dB of the input signal, to allow a near-end speech detector (23) included in the second stage to function correctly, ie to reduce the echo to a level below that at which it might be wrongly identified as near end speech. The second echo canceller, which is disposed after the first echo canceller, functions in a similar manner as the first echo canceller, and, unless inhibited by the detection of near end speech, continues to operate after the first echo canceller is locked until the echo cancelled signal produced by the second echo canceller is approximately equal to zero. <IMAGE>
SE8205839A 1981-10-23 1982-10-14 echo canceller SE8205839L (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US31449081A 1981-10-23 1981-10-23

Publications (2)

Publication Number Publication Date
SE8205839D0 SE8205839D0 (en) 1982-10-14
SE8205839L true SE8205839L (en) 1983-04-24

Family

ID=23220171

Family Applications (1)

Application Number Title Priority Date Filing Date
SE8205839A SE8205839L (en) 1981-10-23 1982-10-14 echo canceller

Country Status (8)

Country Link
JP (1) JPS5881346A (en)
KR (1) KR840002179A (en)
AU (1) AU8965682A (en)
DE (1) DE3238564A1 (en)
FR (1) FR2515454A1 (en)
GB (1) GB2109207A (en)
NL (1) NL8204096A (en)
SE (1) SE8205839L (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1238381A (en) * 1985-03-14 1988-06-21 Ephraim Arnon Multi-stage echo canceller
US4868874A (en) * 1986-04-18 1989-09-19 Hitachi, Ltd. Echo canceller
AU614447B2 (en) * 1988-12-01 1991-08-29 Nec Corporation Echo canceller with means for determining filter coefficients from autocorrelation and cross-correlation coefficients
US5471527A (en) 1993-12-02 1995-11-28 Dsc Communications Corporation Voice enhancement system and method
US5631899A (en) * 1995-05-31 1997-05-20 Lucent Technologies Inc. Acoustic echo canceler
GB2308283A (en) * 1995-12-16 1997-06-18 Ibm System and method for echo cancellation

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1816153B2 (en) * 1968-12-20 1971-04-15 CIRCUIT ARRANGEMENT FOR ECHO SUPPRESSION IN A TALK CIRCUIT ON A FOUR WIRE TRANSMISSION SYSTEM IN THE CASE OF A TRANSITION TO A TWO WIRE TRANSMISSION PATH
US4282411A (en) * 1979-06-04 1981-08-04 Tellabs, Inc. Residual echo suppressor for echo canceller
JPS56153850A (en) * 1980-04-28 1981-11-28 Kokusai Denshin Denwa Co Ltd <Kdd> Echo control system
FR2487144B1 (en) * 1980-07-21 1986-10-24 Trt Telecom Radio Electr DEVICE FOR CANCELING A COMPOSITE ECHO SIGNAL

Also Published As

Publication number Publication date
JPS5881346A (en) 1983-05-16
KR840002179A (en) 1984-06-11
GB2109207A (en) 1983-05-25
NL8204096A (en) 1983-05-16
DE3238564A1 (en) 1983-05-05
AU8965682A (en) 1983-04-28
SE8205839D0 (en) 1982-10-14
FR2515454A1 (en) 1983-04-29

Similar Documents

Publication Publication Date Title
EP0880261A3 (en) Echo canceller and adapting method thereof
EP0721274A3 (en) Method and apparatus for detecting a near-end speech signal
WO1997049196A3 (en) Echo suppressor and non-linear processor of echo canceller
CA2167940A1 (en) Method and apparatus for echo cancelling with double-talk immunity
SE9301184L (en) Ways to perform convergence in an echo suppressor with adaptive filters
CA2205926A1 (en) Echo cancelling arrangements
HK1052602A1 (en) Improved system and method for implementation of an echo canceller
AU582545B2 (en) Echo canceller systems
CA2075843A1 (en) Echo canceller
CA2195261A1 (en) Echo canceler e-side speech detector
JPS6442929A (en) All double data transmission tranceiver
WO2000041330A1 (en) Acoustic echo canceller with fast volume control compensation
EP0766413A3 (en) Fast response gain tracker for echo canceller
AU569977B2 (en) Adaptive echo canceller
SE438582B (en) ECO-ELIMINATOR FOR SYNTHETIZING AN ECO-ELIMINATION SIGNAL
SE8205839L (en) echo canceller
CA2225203A1 (en) Hands-free telephone
AU3135489A (en) Echo canceller
DK0635178T3 (en) Method of avoiding self-oscillation associated with echo suppression
SE8205840L (en) echo canceller
SE8205841L (en) echo canceller
ATE147211T1 (en) METHOD FOR NON-LINEAR SIGNAL PROCESSING IN AN ECHO COMPENSATOR
ES2173092T3 (en) APPARATUS TO REDUCE THE RISK OF INDESEABLE DERIVATIVES OF THE PARAMETERS OF AN ADAPTABLE FILTER USED FOR THE ELIMINATION OF ECO.
JPS6427325A (en) Echo canceller
JPS55123243A (en) Echo canceler

Legal Events

Date Code Title Description
NAV Patent application has lapsed

Ref document number: 8205839-7

Effective date: 19861216

Format of ref document f/p: F