Software speakerphone system and method of operating a speakerphone
US5768364A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1997 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Feb 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/08
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a speakerphone, which operates under software control, transmit and receive signal levels are sampled and compared against one another, with hysteresis, to enable one of two speakerphone modes of operation--either a transmit mode or a receive mode. A single peak detector is multiplexed to sense the transmit and receive signal levels. Fixed attenuators are switched into either the receive signal path or into the transmit signal path, depending upon the current speakerphone operation mode. Signal compression is used to provide for improved mode determination over a wide dynamic range. The level detection and/or attenuation may be performed in software. The speakerphone functions are readily implemented using standard line interfaces and control circuitry. Automatic gain control in the receive mode ensures a constant level of signals at the speakerphone loudspeaker, regardless of telephone line conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.