Adaptive echo cancellation method and device for implementing said method
US5351291A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1992 |
| Grant date | Sep 27, 1994 |
| Priority date | — |
| Expiry date | Aug 7, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/237
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The echo cancellation method includes starting with an arbitrary set of echo filter coefficients. The coefficients are first sequentially re-estimated using a fast converging method. These operations are repeated a predefined number of times, and then the coefficients estimation is switched to a low converging but more precise method. In addition, an adaptive threshold is being defined and readjusted and all filter coefficients lower than said threshold are being discarded. Finally, sampling time boundaries are adaptively defined based on non-discarded filter coefficients with reference to said threshold, and in such a way the final echo cancellation algorithm is adaptive to echo variations (backtracking algorithm).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.