Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning.
The growing challenge of preventing electromagnetic interference (EMI) is particularly acute in the automotive sector. Cars feature increasing numbers of electronic systems, often in close proximity because of packaging constraints. Information systems such as GPS receivers, entertainment systems such as DVD players, and convenience features such as reversing aid cameras all create additional sources of electromagnetic noise. They also increase the number of components that can be affected by interference. The introduction of hybrid and electric powertrains presents further sources of EMI. High-voltage systems and battery packs introduce additional EM noise and create further pressure on vehicle packaging, crowding systems more closely together. As vehicles become more dependent upon the real-time exchange of electronic data, the risks from corruption through EMI vary from mild user inconvenience to major loss of vehicle function.