Secure digital conferencing system
US5150410A · kind A · utility
99Cited by
3References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Apr 11, 1991 |
| Grant date | Sep 22, 1992 |
| Priority date | — |
| Expiry date | Apr 11, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M2203/609
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A secure narrowband digital conferencing system is capable of handing multiple speakers simultaneously and in a full duplex mode. The system uses a multipulse or a code-excited linear predictive (CELP) speech processing algorithm for colding the speech signals of the respective participants. A conference director receives the multipluse or CELP encrypted voice signal streams over normal telephone links, decrypts them, then synthesizes a composite speech signal and uses an analysis-by-synthesis algorithm to compress them, and then encrypts the composite signal and transmits it back to all the participants.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.