Vi fortsätter . att betrakta vår figur: ”EMC från bricka till bricka” och går vidare till filtrering av ledare och kablar. (F) EMC måste tas om hand i alla delar, såväl på elektrisk som på mekanisk systemnivå, och på alla nivåer i en utrustning på ett systematisk och planerat sätt.
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.
En redaktörs reflektioner . EMC-området har utvecklats i olika riktningar sedan det uppstod för runt 100 år sedan. Då utgjordes den drivande kraften av att man ville försäkra sig om att oavsiktlig elektromagnetisk emission från hushållselektronik inte skulle störa de nya rundradiotjänsterna.
EYE ON . Shielding is one of the concepts associated with EMC. Often, for example, mechanical engineers are tasked to build a shielding box, without further specification of ie operating frequencies or desired attenuation.
How much attenuation is reasonable to expect?
The study . “On the EMC Performance of Cable Trays” started with a contact between EMC Services and the Defem company. Their problem was that their design had been given a lot of criticism in the standard EN 50174-2:2000 (on page 25). The standard was found to contain a lot of formulations on EMC, but there was no rationale for the text – nor were they complete.
How to . improve EMC performances of cable installations. The major conclusion from the study is that cable trays are an integral part of the ground structure (actually, it forms the ground if correctly done; nothing else is needed), which can perform as a shielding structure for the enclosed electronic systems. The major quality parameter […]
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.
EYE ON . One fundamental concept in EMC design is zoning. Zoning is easy to understand. It is used in the most varied contexts and situations. Situations covering everything from old communist dictatorships, such as for example the former East Germany (DDR), to city planners and the European Union. Zones are used in order to achieve various properties in demarcated geographic areas, or within volumes. Zoning with application in electronic engineering are also known as the Controlled Electromagnetic Topology.
Vi fortsätter . att betrakta vår figur: ”EMC från bricka till bricka” och går vidare till signalöverföring. EMC måste tas om hand i alla delar, såväl på elektrisk som på mekanisk systemnivå, och på alla nivåer i en utrustning på ett systematisk och planerat sätt.
Behov av . att EMI/RFI-skärma displayer finns i dag i en mängd sammanhang. Några självklara exempel är militära, medicinska och flygapplikationer. Att skärma displayer har tidigare alltid inneburit att man hårt fått kompromissa vad gäller den optiska läsbarheten. Moderna material och tekniker ger dock nya möjligheter med avseende på avstörning, läsbarhet, reflexer och känslighet för växlande temperatur med tillhörande kondens- och isbildningsproblem.