Tactical Consequences of Radio Spectrum Out-of-Band Properties

Tactical communications . for ground-based operations requires many co-located communication systems on combat vehicles. Typical frequency bands for such communications are the 30–88 MHz band for army combat radio and the harmonized NATO band 225–400 MHz. As a result of increasing demands of different communication services and larger bandwidth, the amount of co-located communication systems in these bands is continuously increasing. A consequence of this is that the used frequencies will be less separated, meaning that out-of-band properties will be of severe importance for the performance of the individual systems.

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WHAT IS EMI/EMC?

Michel Mardiguian . Electro Magnetic Interference (EMI) is the generic term describing a situation whereas an electrical disturbance generated by a certain electronic/electrical equipment is causing an undesirable response to another equipment. This undesirable effect may range from a mere nuisance to a catastrophic failure, with associated financial losses or eventually human casualties. The origin of the disturbance could also be a natural phenomena like lightning strokes or ElectroStatic Discharges (ESD). ElectroMagnetic Compatibility (EMC) is just the opposite: EMI being the disease, EMC is the cure, that is the discipline analyzing and preventing or fixing interference problems.

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EMC problems caused by ageing products – a real world example

A new product . must comply with certain EMC requirements in order to fulfill the essential requirements in the EMC directive. Mostly we take it for granted the product maintains its EMC performance through its entire lifetime. From sometimes bitter experience we know that our dear products fail occasionally, needing repair or replacement. Most people relate failure to loss of function but loss of EMC performance can also occur.

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