Method for controlling echo canceling in an echo canceller
US5687229A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1996 |
| Grant date | Nov 11, 1997 |
| Priority date | — |
| Expiry date | Feb 23, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/082
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method for controlling echo canceling in an echo cancellation system using a state machine controller. A far-end speech signal transmitted through a communications channel may be passed through an echo channel to produce an echo signal. The echo signal is summed with a near-end speech signal and transmitted back to the far-end. An echo canceller rejects the echo signal by forming an estimate of the echo signal and subtracting the estimate from the sum of the near-end speech signal and the echo signal. The echo canceller includes a state machine which is configured into a predetermined state of a plurality of states depending on the presence near-end speech signal, far-end speech signal, or both near-end and far-end speech signals. Based on the predetermined state of the state machine, the controller in the state machine controls the update of coefficients of a plurality of adaptive filters. The adaptive filters filter the far-end signal to form the estimate of the echo signal, which is canceled from an output signal provided to an output speech channel at the far-end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.