Methodology for Determination of Circuit Safety Margins for MIL-E-6051 EMC System Test

A MIL-E-6051 electromagnetic co m patib il ity (EMC) te s t includes the establishment of safety margins fo r selected mission c r i t i c a l c irc u its fo r v e r i f ic a t io n o f system co m p atib il ity . Those c irc u its with the lowest safety margins are instrumented fo r tes t in g . A method has been developed fo r the determination of safety margins fo r mission c r i t i c a l c irc u its of the B-1B Avionics and across the e le c tr ic a l interfaces with a l l elements of the B-1B subsystems. The electromagnetic energy coupled between c irc u its and c i r c u i t threshold levels are required fo r determining the safety margins. A coupling analysis computer program, t i t l e d Intrasystem Electromagnetic Com patib ility Analysis Program (IEMCAP) and supplied by the Rome A ir Development Center, was u t i l i z e d to predict the w ire -to -w ire coupling by deta iled modeling of the B-1B. The method of deriving c i r c u i t source and load resistances and threshold level fo r a typ ica l d i f fe re n t ia l l in e d r ive r and receiver c i r c u i t w i l l be demonstrated. The techniques developed fo r analyzing the B-1B Avionics would be useful in determining c i r c u i t safety margins fo r use as c r i t e r ia in selecting c irc u its fo r instrumentation and tes ting fo r other electron ic systems.