Synchronous/asynchronous independent single sideband acoustic telemetry
US4432079A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1981 |
| Grant date | Feb 14, 1984 |
| Priority date | — |
| Expiry date | Nov 2, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J1/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An undersea communications system provides for improved data transmission pabilities. Two separate sources of information respectively modulate the upper and the lower sidebands of an acoustic carrier. The discretely modulated sidebands are simultaneously transmitted without the acoustic carrier or the acoustic carrier can be added to allow asynchronous or synchronous demodulation and use of the two modulating informations. Separation of the information in the two discretely modulated sidebands is assured by shifting the modulating information to ultrasonic regions and filtering out upper and lower sidebands of modulating information. Next, the shifted sidebands are modulated by an acoustic carrier which, optionally, is transmitted along with the discretely modulated upper and lower sidebands. A phase locked loop in the receiver portion assures synchronous demodulation or a crystal oscillator allows asynchronous demodulation of the discretely modulated upper and lower sidebands.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.