NO883355D0 - Echo cancellation. - Google Patents
Echo cancellation.Info
- Publication number
- NO883355D0 NO883355D0 NO883355A NO883355A NO883355D0 NO 883355 D0 NO883355 D0 NO 883355D0 NO 883355 A NO883355 A NO 883355A NO 883355 A NO883355 A NO 883355A NO 883355 D0 NO883355 D0 NO 883355D0
- Authority
- NO
- Norway
- Prior art keywords
- echo
- step width
- signal
- echo canceller
- measuring device
- Prior art date
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>
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3725190 | 1987-07-29 |
Publications (4)
Publication Number | Publication Date |
---|---|
NO883355D0 true NO883355D0 (en) | 1988-07-28 |
NO883355L NO883355L (en) | 1989-01-30 |
NO175400B NO175400B (en) | 1994-06-27 |
NO175400C 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)
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)
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 |
-
1988
- 1988-07-26 DE DE8888112050T patent/DE3875028D1/en not_active Expired - Fee Related
- 1988-07-26 EP EP88112050A patent/EP0303101B1/en not_active Expired - Lifetime
- 1988-07-26 AT AT88112050T patent/ATE81239T1/en not_active IP Right Cessation
- 1988-07-26 ES ES198888112050T patent/ES2035186T3/en not_active Expired - Lifetime
- 1988-07-28 AU AU20110/88A patent/AU586959B2/en not_active Ceased
- 1988-07-28 NO NO883355A patent/NO175400C/en unknown
- 1988-07-29 JP JP63188560A patent/JPH0695653B2/en not_active Expired - Lifetime
-
1992
- 1992-12-30 GR GR920402443T patent/GR3006697T3/el unknown
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 |
NO175400C (en) | 1994-10-05 |
EP0303101A1 (en) | 1989-02-15 |
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