Echo cancellation for channels with unknown time-varying gain
US8077641B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 10, 2006 |
| Grant date | Dec 13, 2011 |
| Priority date | — |
| Expiry date | Nov 25, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/234
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
After an initial training session, a “Dynamic Echo Canceller” (DEC) provides echo cancellation where only access to an input signal and a composite output signal are available, and the input signal is subjected to an unknown variable gain function. In one embodiment, the DEC uses echo cancellation to provide a “clean” copy of a second input signal where only a first input signal and a composite of the first and second input signal is available. An example is a “black box” amplifier coupled to a microphone and a phone line, with access to only the microphone input and a combined output signal where it is desired to retrieve a clean copy of a remote caller signal from the combined output. The DEC is applicable to many fields, including: signal separation; cancellation of echoes caused by impedance mismatches, periodic electrical noise, acoustic echoes caused by acoustic coupling, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.