Echo control device with quick response to sudden echo-path change
US6125179A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 13, 1995 |
| Grant date | Sep 26, 2000 |
| Priority date | — |
| Expiry date | Dec 13, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/082
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An Acoustic Echo Control (AEC) device operates to reduce acoustic echo feedback in a speakerphone. An adaptive echo canceller responds to a far-end speech signal to generate an estimated echo which is subtracted from a near-end speech signal, to generate a compensated near-end speech signal. An Echo Return Loss (ERL) estimator provides an accurate but gradually adjusted estimate of the ERL of the echo canceller. A non-linear processor responds to the ERL estimation and provides additional attenuation to maintain the overall system ERL. The AEC device also incorporates dual talking mode detectors, one for the adaptive filter and one for the non-linear processor, to detect a plurality of talking modes, which are used to control the adaptation of the adaptive filter and the attenuation provided by the non-linear processor. A convergence indicator responds to the sudden echo path changes, and quickly corrects the ERL estimation; thereby adjusting the talking mode detector and the non-linear processor accordingly to maintain the overall system ERL and stability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.