Matra

About: Matra is a based out in . It is known for research contribution in the topics: Signal & Detector. The organization has 1330 authors who have published 1216 publications receiving 17967 citations.

Telematic services via satellite in Europe

Abstract: The word ‘telematics’ was used for the first time in France in 1978 by Simon Nora and Alain Minc; it is a contraction of the French words ‘tetecommunications’ and ‘informatique’, and defines a marriage between computers and data transmission networks. This paper describes the five systems which will be implemented to provide telematic services via satellite in Europe during the next few years: EUTELSAT, TELECOM 1, UNISAT, DFS and ITALSAT. The main characteristics of the ‘special service’ transponders are presented, showing that, in Europe, (a) 2 to 5 transponders per satellite will be devoted to the special (telematic) services; (b) 4 satellites out of the 5 use the 12.5–12.75 GHz down-link band for this purpose (only ITALSAT uses the 20 GHz down-link for the same purpose), and (c) e.i.r.p.s at 12 GHz are in the range 40–49 dBW. The ground and space segments corresponding to this new service are presented. The main peculiarity of the ground segment is the exclusive use of ‘small’ earth-stations equipped with fixed antennas and SCPC or 25–60 Mb/s TDMA multiple access equipment. Telematic services include videoconference at 2048 kb/s, voice services, computer-to-computer transfer of data, data distribution, remote printing, electronic mail, high-speed facsimile, offshore voice and data services, digital network overflow, transatlantic digital business etc… Customer bit rates start from 2.4, 4.8, 9.6 and 32 kb/s (for TELECOM 1) up to 2048 kb/s by 64 kb/s steps. Bit error rates are maintained below 10−6 (standard) or 10−10 (higher grade) during 99 per cent of the year using FEC. The five networks for telematics via satellite in Europe are independent. A large efficiency improvement of the different services should be obtained through a future interconnection of the various networks via intersatellite links.

Filling a container with gas under pressure

Abstract: When filling a tank with xenon or krypton gases for use as a propellant in satellites, it is necessary to proceed slowly to allow heat to dissipate. The invention deals with this problem by withdrawing gas from the tank, cooling it, and re-introducing the cooled gas into the tank. The circulation of gas from and back to the tank is preferably achieved by a thermosyphonic action. The gas is preferably liquefied when it is cooled to give a strong thermosyphonic action and may be evaporated again before being returned to the tank. In a variation of the invention, the temperature of the tank is prevented from falling below a critical minimum temperature during depressurization of the tank by recirculating and heating some of the fluid during depressurization.

Displacement measuring apparatus with a code wheel

Abstract: The device, applicable in particular to measuring the distance traveled by a vehicle, comprises a wheel (12) driven in rotation and provided with two binary digits representative pins constituted one by a hole (42) passing through the wheel, the other a hole connected to the edge of the closest wheel by a narrow slot. The sensor comprises two coils placed face to face, one on each side of the wheel, associated with means for detecting their mutual inductance. A wheel-clock (14) is keyed on the same shaft (10) that the pattern wheel.

Autonomous fluid flow limiting device for a conduit and aircraft fuel installation incorporating it

Abstract: Gas or liquid passes from an input chamber (2) to an output chamber (3) via orifices (10,11) controlled by valves (12,19). The two valves are mechanically linked (20) and their position is controlled by a membrane (13) that is subjected to the input and output pressure difference (P1,P2). Low output pressure results in the input valve (12) opening and the output valve (19) closing, and vice versa. The flow adjustment is by springs and screws (15,17,16,18)