Confidential communication system
US4817141A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 15, 1987 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | Apr 15, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04K1/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The respective feature parameters extracted from a speech signal is converted into the corresponding line spectrum data in a first frequency band obtained by dividing the speech signal frequency band. Each of the line spectrum data is allocated previously to each one of the feature parameters. The extracted feature parameters are further converted into the corresponding line spectrum data in the other divided frequency bands other than the first frequency band. The converted line spectrum data are multiplexed for transmission. The corresponding line spectrum data in the divided frequency bands allocated to the same feature parameter are logically added to restore the feature parameters. Thus higher confidential communication is realized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.