1.Sources of electro-magnetic interferences

The sources of electro-magnetic interferences are categorized into internal and external sources.

Transmission of electro-magnetic interferences

（1） When the source of interference is of high frequencies with the wavelength of interfering signal less than the structural dimensions of the interfered object, or the distance between the source of interference and the interfered object r﹥﹥λ／2л, the source of interference can be treated as radiation field that emits electro-magnetic energyinto the channel of interfered object in the form of plane electro-magnetic waves.

（2） Taking the forms of electrical leakage and coupling, the interfering signals enter the circuit, equipment and system through the insulating supporters (including air).

（3） Interfering signals enter circuits, equipment and systems by direct conduction.

2.Designing method of electro-magnetic compatibility

（1）Grounding

（2）Shielding

（3）Filtering

（4）Other methods used for suppression of interference

3.Basic measuring method of electro-magnetic compatibility

（1） Measurement of emission of electro-magnetic radiation (RE)

（2） Measurement of sensitivity of electro-magnetic radiation (RS)

（3） Measurement of conduction and emission (CE)