Electromagnetic compatibility(EMC) refers to the ability of a device, network or system to operate satisfactorily in an electromagnetic environment. This device (equipment, system) should not itself cause electromagnetic interference that would be unacceptable to any apparatus, system or equipment present in that environment.
EMC includes spark interference, interference with telecommunication lines caused by power installations, atmospheric discharges, Lightning Electromagnetic Pulses( LEMP), nuclear electromagnetic pulses, Nuclear Electromagnetic Pulses( NEMP), and Switching Electromagnetic Pulses( SEMP) caused by switching operations.
The International Electrotechnical Commission( IEC) has defined these requirements in IEC Standard 61000-1-1, and DINin VDE 0870. DIN IEC 50, Part 902 describes that EMC from an information technology point of view means the simultaneous presence of a useful signal and an interference signal without loss ofinformation.
The Europe-wide standards for EMC are defined in the Electromagnetic Compatibility Act(EMVG) and all corresponding specifications have been legally binding since January 1, 1996. The standards for EMC apply to emission, EN 50081-1, as well as to immunity, EN 50082-2, for both domestic and commercial use. The standards EN 55022 and EN 60555 describe the emissions for equipment, as well as of cables required to operate the equipment. Proof of compliance with the European standard for interference radiation (EN 55022) and interference immunity (EN 55024) is provided by certification with the CE mark.
EN 50081-1 (DIN VDE 0839 Part 81-1/3.93): Basic technical standard for electromagnetic compatibility. Part 1 of this standard deals with interference emission in residential, business and commercial areas as well as in small businesses.
EN 55022 (DIN VDE 0878 Part 3/11.89): This standard deals with the limits and measurement methods for radio interference from information technology equipment (ITE). Emission limits are specified for an overall system consisting of passive and active components: Radio interference voltages at the mains connection from 150 kHz to 30 MHz (measured on lines ) and electrical interference field strength in the range from 30 MHz to 1000 MHz (measured at distances of 3 m, 10 m and 30 m). The newer edition, which comes into force in October 2010, prescribes EMC tests up to 6 GHz. This standard describes the measurement setup and methods. The standard distinguishes between two classes: Class A for commercial operations and environments using a protective distance of 30 m, and Class B for equipment and devices for which there are no sales restrictions
EN 55011 (DIN VDE 0875 Part 11/7.92): This standard regulates the limit values and the measurement methods for radio interference from industrial, scientific and medical high- frequency equipment
EN 50082-1 (DIN VDE 0839 Part 82-1/3.93): Basic technical standard for electromagnetic compatibility. Part 1 of this standard deals with interference immunity in residential, commercial and small business environments. The current requirements regarding EMC are still very incomplete; moreover, there is no clear legislation in Europe.