OVERVIEW -> Electromagnetic Interference (EMI)

EMI Sources

In order for EMI to occur, there must be a method or "path" for the electromagnetic energy from the culprit to couple to the victim. The energy may be in the form of electric or magnetic fields or currents and voltages. The energy can be produced by either natural or man-made sources, however man-made dominates. The coupling method for this energy falls into two categories: conducted and radiated. The coupling paths may sometimes combine methods and make the paths difficult to identify.

Conducted coupling involves the extensive wiring and cabling typically found on spacecraft. The photos below show the large amount of cabling associated with payloads in the cargo bay of the Shuttle. EMI from the culprit is transferred through the power and data lines to the victim in the form of noise voltages and currents. The victim is sensitive to these noise voltages or currents and its operation becomes impeded.

back to Electromagnetic Effects Overview