NO175400C - echo cancellation - Google Patents

echo cancellation

Info

Publication number
NO175400C
NO175400C NO883355A NO883355A NO175400C NO 175400 C NO175400 C NO 175400C NO 883355 A NO883355 A NO 883355A NO 883355 A NO883355 A NO 883355A NO 175400 C NO175400 C NO 175400C
Authority
NO
Norway
Prior art keywords
echo
step width
signal
echo canceller
measuring device
Prior art date
Application number
NO883355A
Other languages
Norwegian (no)
Other versions
NO175400B (en
NO883355L (en
NO883355D0 (en
Inventor
Dirsko Von Pfeil
Original Assignee
Siemens Ag
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 Siemens Ag filed Critical Siemens Ag
Publication of NO883355D0 publication Critical patent/NO883355D0/en
Publication of NO883355L publication Critical patent/NO883355L/en
Publication of NO175400B publication Critical patent/NO175400B/en
Publication of NO175400C publication Critical patent/NO175400C/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
    • H04B3/234—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)
  • Primary Cells (AREA)
  • Bidirectional Digital Transmission (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
  • Radio Relay Systems (AREA)

Abstract

The step width with which a transversal filter (21) in the echo canceller (10) is set is also dependent on the size of the error signal (F) at the transmission path output (13). As a result, when a large signal (F) occurs, the echo canceller (10) quickly compensates with a large step width for the echo which causes the greatest interference and subsequently, when a smaller error signal (F) occurs, effectively cancels the residual echo with a smaller step width. In the case of duplex operation which cannot be reliably identified, a large signal is simulated. The aim is to prevent this effect. An echo measuring device (26) identifies duplex operation with relative reliability and sends a step width setting signal (S) to the transversal filter (21). A frame adaptation memory (28) detects a phase shift or slip and then resets the echo measuring device (26) with a reset signal (R). The echo canceller is used in international gateway exchanges. <IMAGE>
NO883355A 1987-07-29 1988-07-28 echo cancellation NO175400C (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3725190 1987-07-29

Publications (4)

Publication Number Publication Date
NO883355D0 NO883355D0 (en) 1988-07-28
NO883355L NO883355L (en) 1989-01-30
NO175400B NO175400B (en) 1994-06-27
NO175400C true NO175400C (en) 1994-10-05

Family

ID=6332662

Family Applications (1)

Application Number Title Priority Date Filing Date
NO883355A NO175400C (en) 1987-07-29 1988-07-28 echo cancellation

Country Status (8)

Country Link
EP (1) EP0303101B1 (en)
JP (1) JPH0695653B2 (en)
AT (1) ATE81239T1 (en)
AU (1) AU586959B2 (en)
DE (1) DE3875028D1 (en)
ES (1) ES2035186T3 (en)
GR (1) GR3006697T3 (en)
NO (1) NO175400C (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU604137B2 (en) * 1987-07-20 1990-12-06 Nec Corporation Echo canceller
DE19816358C2 (en) * 1998-04-03 2000-04-27 Deutsche Telekom Ag Method for controlling the step size of an echo canceller with an adaptive filter
EP1301018A1 (en) * 2001-10-02 2003-04-09 Alcatel Apparatus and method for modifying a digital signal in the coded domain

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3327467A1 (en) * 1983-07-29 1985-02-14 Siemens AG, 1000 Berlin und 8000 München METHOD AND CIRCUIT ARRANGEMENT FOR COMPENSATING ECHO SIGNALS
JPS6053336A (en) * 1983-09-02 1985-03-27 Nec Corp Echo canceller
FR2564667B1 (en) * 1984-05-15 1986-09-19 Trt Telecom Radio Electr DEVICE FOR CONTROLLING AN ECHO CANCELER AND A CENTER SCREENER
EP0231854B1 (en) * 1986-01-30 1991-04-03 Siemens Aktiengesellschaft Echo compensator

Also Published As

Publication number Publication date
ATE81239T1 (en) 1992-10-15
AU586959B2 (en) 1989-07-27
DE3875028D1 (en) 1992-11-05
NO175400B (en) 1994-06-27
ES2035186T3 (en) 1993-04-16
GR3006697T3 (en) 1993-06-30
JPH0695653B2 (en) 1994-11-24
EP0303101B1 (en) 1992-09-30
AU2011088A (en) 1989-02-16
NO883355L (en) 1989-01-30
JPS6444636A (en) 1989-02-17
NO883355D0 (en) 1988-07-28
EP0303101A1 (en) 1989-02-15

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