Full duplex speakerphone
US5657384A · kind A · utility
34Cited by
3References
30Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 10, 1995 |
| Grant date | Aug 12, 1997 |
| Priority date | — |
| Expiry date | Mar 10, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/082
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A full duplex speakerphone for connection to a telephone system employs adaptive FIR filters for acoustic and electrical echo cancellation in a novel combination with analog gain controls responsive to incoming signal levels and a transmit level control responsive to the receive signal power level. The particular combination minimizes the amount of digital signal processing required to maintain full duplex operation by holding the signal dynamic range within predetermined limits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.