Method and apparatus for transmitting and receiving electrical speech signals transmitted in ciphered or coded form
US3959592A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 17, 1973 |
| Grant date | May 25, 1976 |
| Priority date | — |
| Expiry date | Dec 17, 1993 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L19/00
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method of, and apparatus for, transmitting and receiving electrical speech signals transmitted in ciphered form, wherein at the transmitter end there are formed in sections or intervals from the speech signals to be transmitted, by frequency analysis, signal components or parameter signals containing frequency spectrum-, voiced/voiceless information- and fundamental sound pitch coefficients, these signal components are ciphered, the ciphered signal components or parameter signals are transformed into a transmission signal and this transmission signal is transmitted over a transmission channel, and at the receiver end there is reobtained from the transmission signal the ciphered signal components or parameter signals and deciphered, and from the thus-obtained deciphered signal components or parameter signals there is generated by synthesis a speech signal which is similar to the original speech signal. According to the invention there is employed at the transmitter end for the synthesis of the transmission signal harmonic frequencies of a common fundamental frequency with constant fundamental period at least for each signal section or signal interval, the amplitudes of the individ…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.