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Satellite Communications System with Low Cost Earth Stations

IP.com Disclosure Number: IPCOM000051635D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Noel, FE: AUTHOR

Abstract

The drawings depict a satellite communications system in which earth station costs are reduced by using conventional teleprocessing line modems in place of burst modems. Burst modems are used at the communications satellite.

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Satellite Communications System with Low Cost Earth Stations

The drawings depict a satellite communications system in which earth station costs are reduced by using conventional teleprocessing line modems in place of burst modems. Burst modems are used at the communications satellite.

Fig. 1 shows a communications satellite 10 and, for ease of illustration, a pair of earth stations 12 and 14. A typical satellite communications system would naturally include a greater number of earth stations. Any reference in the following description to a component in earth station 12 may be construed as a reference to a corresponding component in earth station 14 or in any other earth station (not shown) in the system. Earth station 12 includes data communications equipment 16 and a line modem 18. Line modem 18 is a conventional teleprocessing line modem instead of a burst modem. Line modem 18 is connected to an antenna 20 which transmits data to the satellite 10 (up link) or receives data from the satellite 10 (down link).

Fig. 2 shows the architecture for satellite 10. A burst modem 22 receives data from an earth station. The demodulated data is applied to a clocking circuit 24, a data stream detection circuit 26, and a retiming circuit 28. Clocking circuit 24 extracts clocking information from the up link data to generate timing signals applied both to retiming circuits 28 and to a second burst modem 30.

Data stream detection circuit 26 must be capable of recognizing an addr...