Procedure and device for adaptive digital cancellation of the echo generated in telephone connections with time-variant characteristics
US5418849A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1992 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Apr 16, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/23
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A procedure and device are described for cancellation of the echo produced in telephone connections with electrical time-variant characteristics such as for example those affected by phase roll. The echo canceller obtained in accordance with the procedure which is the object of this invention produces an estimate of the echo signal by means of appropriate digital filtering of the signal originated by the far-end talker. The estimated echo is then subtracted from the actual echo. Filtering is activated by an IIR digital filter whose adaptive coefficients are updated by use of an adaptive algorithm based on decimation of the square error. The high convergence speed of said algorithm in the calculation of the coefficient correction step allows a correct estimate of the echo even in case of connections affected by phase roll.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.