EP 0044845 A1 19820203 - PROCESS AND DEVICE FOR PROTECTING THE TRANSMISSION OF VOCAL SIGNALS.
Title (en)
PROCESS AND DEVICE FOR PROTECTING THE TRANSMISSION OF VOCAL SIGNALS.
Title (de)
VERFAHREN UND SCHALTUNGSANORDNUNG ZUR GESICHERTEN ÜBERTRAGUNG VON SPRACHSIGNALEN.
Title (fr)
PROCEDE ET DISPOSITIF POUR LA TRANSMISSION PROTEGEE DE SIGNAUX VOCAUX.
Publication
Application
Priority
CH 81780 A 19800201
Abstract (en)
[origin: WO8102234A1] Process and device for protecting the transmission of vocal signals along a limited band-width analog transmission channel (for instance a vocal CCITT channel), protecting against illicite listening. By exploiting the speech information perceived by the human ear, the vocal signal to be transmitted is digitalized and undergoes a corresponding information reduction (A(f)) based on Fourier"s transformation. The necessary information protection can thereby be obtained in the subsequent coding, with respect to the transmission distortions and the modulation is optimally adapted to the transmission behaviour. The digital form existing before this coding can be easily digitalized so that the transmitted analog signal is totally incomprehensible and can not be reconstituted even through the modem methods of analysis, while for the authorized listeners a good intelligibility subsists. By this process, through the modern means of the digital signal processing technique, an optimal solution to the safe analog transmission of speech can be achieved.
Abstract (fr)
Le procede et le dispositif correspondant pour la transmission protegee de signaux vocaux sur un canal de transmission analogique a bande limitee (par exemple un canal vocal CCITT), protegent contre l'ecoute clandestine. En exploitant l'information de la parole percue par l'ouie humaine, le signal vocal a transmettre est numerise et soumis a une reduction de l'information (A (f)) correspondante basee sur la transformation de Fourier. Ceci permet de realiser la protection necessaire de l'information dans le codage subsequent, relativement aux distorsions de la transmission, et la modulation adaptee de maniere optimale au comportement de la transmission. La forme numerique existante avant ce codage se laisse facilement chiffrer de facon telle que le signal analogique transmis soit totalement incomprehensible et ne puisse pas etre reconstitue meme avec les methodes modernes d'analyse, tandis que pour les ecouteurs autorises subsiste une bonne intelligibilite. Ce procede offre la possibilite d'obtenir, par des moyens modernes de la technique numerique de traitement des signaux, une solution optimale pour la transmission analogique sure de la parole.
IPC 1-7
IPC 8 full level
CPC (source: EP)
H04K 1/00 (2013.01)
Designated contracting state (EPC)
DE FR GB NL SE
DOCDB simple family (publication)
WO 8102234 A1 19810806; CH 649181 A5 19850430; DE 3164634 D1 19840816; EP 0044845 A1 19820203; EP 0044845 B1 19840711; JP S57500089 A 19820114
DOCDB simple family (application)
CH 8100010 W 19810130; CH 81780 A 19800201; DE 3164634 T 19810130; EP 81900305 A 19810130; JP 50053481 A 19810130