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What is electromagnetic compatibility (EMC)?
Electromagnetic compatibility (EMC) is the ability of electronic and electrical equipment and systems to operate without adversely affecting other electrical or electronic equipment or being affected by
other sources of interference such as power line transients, radio frequency (RF) signals, digital pulses, lightning, or cosmic influences.
What is electromagnetic interference (EMI)?
Electromagnetic interference (EMI) originates from natural or manmade sources, which can potentially interrupt electronic equipment and systems and prevent them from functioning properly.
EMI causes undesirable effects in telecommunications, data processing equipment, television, radios, automotive electronics, avionics, space systems, medical devices, and numerous other electronic
devices.
How does EMI affect electronic systems?
EMI can cause disruptions by radiating through the air and affect an electronic module directly or indirectly by coupling onto wire harnesses or power leads. It can also be conducted to the device on the
power leads in the form of RF or audio signals, power line transients, or switching transients.
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In the home: distortion of television picture and sound.
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In a vehicle: noise and static in radio and sound systems, disruption of vehicular component functions
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In a business: interference in automatic control systems
What are some sources of electromagnetic emissions (EME)?
Electromagnetic emissions (EME) come from unfiltered power lines, unshielded circuits producing RF energy, or switching power supplies that produce pulses with fast rise or fall times.
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Radiated (Examples: power lines, pulsed circuits, and improperly designed electronic systems).
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Conducted (Examples: switching transients, motor noise on the power lines, RF on the power leads).
What is the difference between conducted interference and radiated interference?
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Conducted Interference: These interference signals move from one point to another on the power supply leads between a source and a receptor. Two possible sources of these signals are (1) the circuits
within the device and (2) radiated energy induced onto the wires of the device.
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Radiated Interference: These interference signals are transferred via an electromagnetic (EM) field produced by a signal source over a propagation path through the air. The source of these signals can be
external (e.g., radio and TV stations) or internal (e.g., unshielded radio frequency (RF) circuits and switching power supplies) to an electronic system.
Why must electronic equipment be tested for EMC?
In today’s environment, there are numerous sources of RF energy, and it is increasing. Because the operation of some devices are critical, such as heart pacemakers, hospital bedside monitors, and
instrumentation in a surgical suite, the FDA requires it. Vehicle manufacturers require testing to ensure automotive electronic safety because engine and transmission systems could cause havoc if they do not function properly. Some governmental agencies
such as the European Union require electronic equipment be EMC tested before it can be marketed in Europe.
What can I expect when I request an EMC test lab to perform EMC testing?
You should expect that the equipment you send to be tested is handled professionally by competent personnel. You should be allowed to visit the lab and observe the testing of your product as well as have
your questions answered. Testing should be performed without bias and the results kept confidential. If your equipment experiences malfunctions or noncompliances, the lab should inform you of the problems encountered. If you need assistance to modify the
equipment, the lab should have the ability to provide that engineering assistance at a nominal cost. Once the device is repaired, the lab should retest it to ensure the modification is good over the entire test frequency range for emissions and immunity.
Why choose the Southwest Research Institute (SwRI) EMCR laboratory for my EMC needs?
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First and foremost, SwRI is your one-stop source for your engineering design, test, and analysis needs.
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Second, the SwRI electromagnetic compatibility research (EMCR) laboratory, established in 1956,
offers clients high-quality EMC services.
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The staff are certified National Association of Radio and Telecommunication Engineers Inc. (NARTE) engineers and technicians.
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The electromagnetic compatibility research lab is accredited for ISO 17025 by the
American Association of Laboratory Accreditation (A2LA).
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In addition, there are other services available to our clients at SwRI including
environmental
sciences (vibration, altitude, salt/fog, seismic testing),
fire technology (burn facilities, hazardous
gases, safety/flammability).
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Other capabilities include:
For more information or questions
about electromagnetic compatibility capabilities at SwRI
or how you can contract with SwRI, please contact
Jenny Ferren at
jferren@swri.org or (210) 522-2329. We can offer
you insights about how to specify the best approach to
solving your EMC problem.
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Contact Information |
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Jenny Ferren
Electromagnetic Compatibility
(210) 522-2329
jferren@swri.org |
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Related Terminology |
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electromagnetic interference
electromagnetic compatibility
electromagnetic compatibility research A2LA ISO 17025 automotive components testing
whole vehicle testing component testing subsystem evaluations immunity testing radiated
emissions measurement electromagnetic
emissions detection susceptibility problems immunity problems |
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Related Links |
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Electromagnetic Compatibility Research Lab
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Southwest Research Institute® (SwRI®), headquartered
in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied
engineering and physical sciences research and development organization with
12
technical divisions.
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