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EMI/EMP Resistant Data Bus

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Final techincal rept. 1 Oct 1973-19 Sep 1975

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This document is the final report of a development program concerned with the design and fabrication of an eight station EMIEMP resistant avionic data bus. Airborne avionics systems are moving toward the use of party line multiplex data buses for the transmission of the growing number of digital signals found in modern aircraft. Optoelectronic technology provides a data bus interface system consistent with military requirements that is potentially superior to wire techniques-particularily in the areas of ground loop noise immunity and EMIEMP sensitivity. The passive optical couplers developed on the initial phase of this program are a necessity for the realization of a true optical bus. The optical couplers are required in an optoelectronic data bus so that each station can receive optical signals from the bus and transmit optical signals onto the bus. By this means, each station on the bus can communicate with every other station. The report emphasizes the design approach and characteristics associated with the critical opto-electronic interfaces. Overall system description is also presented. The system features eight Multiplex Terminal Units MTU inter-connected with a nine port radial coupler. Plugable optical interfaces are employed with fiber optic cable lengths of 10 ft., 20 ft. , 30 ft., and 50 ft. This provides for a maximum bus length of 100 ft. The system uses unipolar Manchester coding on the optical bus with a data rate of 10 M bits and a worst case bit error rate of 1 in 100 million.

Subject Categories:

  • Aircraft
  • Non-Radio Communications

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