Echo reduction
US7154867B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 6, 2001 |
| Grant date | Dec 26, 2006 |
| Priority date | — |
| Expiry date | Jul 30, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/23
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
This invention provides a technique to reduce echoes not adequately attenuated by echo cancellers during initial periods of voice communication. Signals transmitted across communication networks are often reflected back to the caller resulting in echo. Echo cancellers are employed in the communication system to cancel this effect in order to maintain a high quality transmission. However, echo cancellers require time to detect, adapt, and effectively remove echo, often resulting in echo during the initial moments of the call and thereby degrading the quality of service. By installing an attenuation device into the communication system, all signals that pass through it are reduced to a preset value for a set period of time. This reduces any echo below a detectable threshold. After the period of time expires, the attenuation device allows the signal to pass unaffected, by which time the echo cancellers have adaptively adjusted to any echoes in the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.