EMI hardening of Launcher Interface Unit - A case study

Solving the EMI problems and achieving the EMC is not at all difficult if we analyse the problems step by step and eliminate the problems in different steps with proper EMC measures or fixes. Estimation and identification of simulatory/monitoring equipment noise levels are most essential before they use. Some times, the cable lengths of simulating/monitoring equipment will raise the spectrum of emissions even though they are at cold condition. Spectrum of emissions from the unit under test will be leaked through these cables and radiates. Cable lengths will corrupts the isolation between system and simulating/monitoring equipment. A careful grounding scheme has to follow to ground the shield of the cables at number of places by correlating the wave lengths and the currents in which they areflowing. Using 1553B cable's shield as a separate line is not at all advisable. This will become the cause for generation of the un-predicted spectrum of emissions. In this paper the authors highlighted about the analysis carried out to counter EMI problems arose and the steps taken to minimise the noise with suitable and simple EMC measures.