The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 22, 1992
Filed:
Apr. 11, 1991
Applicant:
Inventor:
John Bertrand, Upper Nyack, NY (US);
Assignee:
ITT Corporation, New York, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04K / ; H04Q / ; H04B / ; H04M / ;
U.S. Cl.
CPC ...
380 28 ; 370 62 ; 375-3 ; 379202 ;
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.