Electromagnetic Interference is a electromagnetic phenomenon which is caused by nature and manmade, and it can degrade the performance of the system/device.
The words electromagnetic interference/radio frequency interference is sometimes used interchangeably. This is not exactly correct. Radio frequency interference is the degradation in the reception of a wanted signal caused by radio frequency disturbance, which is an electromagnetic disturbance.
The electromagnetic interference can travel from the source to the receptor, which may be a device or equipment or system. We use the receptor to convey that it receives electromagnetic interference. Electromagnetic transfer mechanisms may vary depending on modes of operation, propagation conditions, and other variables. The propagation paths that exist for signal transfer from the transmitters to a receiver with in a RF environment of a radio communications band can be numerous. The primary mechanisms by which electromagnetic interference so coupled from its source, or sources to the receptor are radiation and conduction [1].