Half-duplex controller
US5764753A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 1995 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Sep 29, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/234
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A double-talk detector for an echo canceller includes power estimators (60) and (62) which are utilized to measure the ERLE value in a calculator (64). This ERLE is stored in a register (70) when it is the largest value generated. This register (70) is updated whenever a new and better ERLE occurs. A fraction of the value in register (70) is utilized as an input to a comparator (88), and then compared to the current ERIE value. If the current ERLE differs from the SERLE in register (70) an inhibit signal is generated for blocking the updates of an adaptive filter (40). The value stored in the register (70) is periodically decremented to reduce the value thereof. This decrement operation is performed in response to detection of an utterance from the far-end. A half-Duplex operation is provided with two attentuators (352) and (354) to provide a switching operation and allow only one side access to the communication path. Speech, or the occurrence of an utterance is monitored at each end by comparing the raw input power at each end to a scaled up background noise power for that end. Different scaling factors for speech detection, or utterance detection, are provided, there being a hig…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.