Echo canceller with double talk detector
Abstract
The echo canceller of the present invention comprises a means for estimating an echo gain from a reception signal level and a transmission signal level; a first level calculating means (5) for calculating logarithmically converted power of a reception signal level; a second level calculating means (16) for calculating logarithmically converted power of a transmission signal level; an echo gain estimation means (19) for estimating an echo gain based on the reception signal level and the transmission signal level; and an echo level estimating means (18) for adding the estimated echo gain to said reception signal level to obtain an estimated echo level, a third level calculating means (6) for calculating logarithmically converted power of a residual signal level; and a comparison means (19) for comparing the estimated echo level with the residual signal level after the echo cancellation; wherein the echo of the reception signal contained in the transmission signal is canceled when said estimated echo level exceeds the value obtained by adding a margin to the residual signal level.

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Projected expiry passed 30 January 2017, 9.6 years ago.
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1 sheet
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Every citation, both ways
| Document | Relation | Office | Category | Cited during | Relevant claims |
|---|---|---|---|---|---|
| US4878232A | Cites | United States of America | A | Search report | 1-14 |
| US5247512A | Cites | United States of America | A | Search report | 1-14 |
| US5483594A | Cites | United States of America | A | Search report | 1-14 |
18 members in 7 offices
Priority claims4
| Document | Office | Kind | Date |
|---|---|---|---|
| 10553896 | Japan | A | |
| 10553896 | Japan | – | |
| 10553896 | – | – | – |
| JP19960105538 | – | – | – |
Members18
| Document | Office | Kind | |
|---|---|---|---|
| CA2199566A1 | Canada | A1 | |
| EP0803990A2 | European Patent Office (EPO) | A2 | |
| KR970072857A | Republic of Korea | A | |
| JPH1013310A | Japan | A | |
| CN1173089A | China | A | |
| KR100225055B1 | Republic of Korea | B1 | |
| TW432855B | Taiwan Province of China | B | |
| EP0803990A3This record | European Patent Office (EPO) | A3 | |
| CN1080506C | China | C | |
| JP2002198871A | Japan | A | |
| US6445792B1 | United States of America | B1 | |
| CN1379576A | China | A | |
| JP3386327B2 | Japan | B2 | |
| CN1157040C | China | C | |
| CN1538631A | China | A | |
| CA2199566C | Canada | C | |
| JP3631459B2 | Japan | B2 | |
| CN100433576C | China | C |
7 legal events, as the office reported them to INPADOC
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Point at a mark for the eventEvents
| Event | Code | |
|---|---|---|
| Application deemed to be withdrawnWithdrawn18D | 18D | |
| Information on the status of an ep patent application or granted ep patentGrantedSTATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWNSTAA | STAA | |
| Designated contracting statesAK | AK | |
| Search report despatchedORIGINAL CODE: 0009013PUAL | PUAL | |
| Information provided on ipc code assigned before grant7H 04B 3/23 A, 7H 04M 9/08 BRIC1 | RIC1 | |
| Designated contracting statesAK | AK | |
| Public reference made under article 153(3) epc to a published international application that has entered the european phaseORIGINAL CODE: 0009012PUAI | PUAI |
Numbers
- Publication
- 0803990
- Publication, DOCDB
- 0803990
- Publication, EPODOC
- EP0803990
- Application
- 97101440
- Application, DOCDB
- 97101440
- Application, EPODOC
- EP19970101440
Titles3
- German
- Echounterdrücker mit Gegensprechdetektor
- English
- Echo canceller with double talk detector
- French
- Annuleur d'écho avec détecteur de double parole
Classification
- CPC, 1
- H04B3/234
- IPC, 1
- H04B3 23
Designated states1
- Contracting states, 1
- United Kingdom