Interference
Electromagnetic interference (also: interference emission ) describes the undesirable property of an electrical or electronic device to work as an electromagnetic source of interference and thereby interfere with other devices. The permissible interference emission is regulated within the EU by the protection requirements of the EMC directive ( electromagnetic compatibility ), which refers to the relevant standards. These standards contain the limit values for certain high frequency ranges , device categories and environments within which interference immunity should be guaranteed. Different standards apply to aviation equipment, usually the DO-160, section 21, RTCA standard is used as the basis. The European document EUROCAE ED-14 is identical to the DO-160.
The emissions are usually limited by appropriate limit values. In the theoretical ideal case, the disturbance variable to be measured would be zero. In practice, radio interference suppression is required for most devices today .
A distinction is made between conducted interference emission ('radio interference voltage') and field-related interference emission ('radio interference radiation').
The English term for emitted interference is Electromagnetic Interference (EMI).
example
The picture shows an example of an EMC measurement of the radiated interference in a frequency measuring range from 150 kHz to 108 MHz. In order to avoid external influences, the EMC test must be carried out in a shielded chamber . All measured values of the blue curve are below the maximum permissible limit values of the red stepped curve. The exam is therefore considered passed.
See also
literature
- Georg Durcansky: EMC-compliant device design . Franzis Verlag GmbH, Poing 1995, ISBN 3-7723-5386-X .