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Introduction to Electromagnetic Compliance and Precompliance Testing

Electromagnetic Compliance (EMC) and Precompliance Testing are methods of ensuring that electronic devices don’t overly emit unwanted electromagnetic (EM) radiation or electrical fields and are adequately immune to external EM radiation or electrical fields. There are specific EMC standard that Countries and regions require to be passed before products can be legally sold in those areas. As there is generally a relatively low first-time pass rate for EMC testing (~50%) many organizations use Precompliance testing in-house or with rented services and facilitates to help ensure their product designs are better prepared for EMC testing.

The exact tests performed for EMC are diverse and highly specific to the type of electronic product and its intended use. Hence, various Industries, such as automotive, aerospace, and medical, along with military and governments also have specific EMC standard requirements that must be met for their facilities and equipment. Generally, EMC and EMC Precompliance testing involves conducted emissions, conducted immunity, radiated immunity, and radiated emissions testing, along with other forms of harmonic, flicker, and pulse testing.

Country and/or Region Specific EMC Standards

• United States  FCC Part 15 Rules
• Canada  Industry Canada ICES Rules
• Europe  European Standards (EMC)
• Australia & New Zealand  EMC standards list
• Japan  VCCI
• China  CNCA
• Russia EASC (GOST)

Industry Specific International Standards

• Medical
      IEC 60601-1-2

• Automotive
      SAE
      ISO7637
      IEC CISPR-25
      Automotive Directive (“E-mark” for Europe).
      ISO1145-1
      ISO1145-2

• Military
      MIL-STD-461
      DEF STAN 59/411 ( common in NATO)
      MIL-STD-704 (for aircraft)
      MIL-STD-1275 (for land vehicles)
      MIL-STD-1399 (for ships)

Therefore, several types of test equipment is used for EMC testing that is well specified, though there is a wider range of test equipment used for Precompliance testing as there are no specific requirements for Precompliance testing other than that setout by the company doing the testing. EMC testing is generally performed in Open Area Test Sites (OATS), Over-the-air Test ranges, Anechoic Chambers, and Semi-anechoic Chambers. Precompliance testing may be performed in typical lab benches, in chamber used for EMC testing, or in specialized testing chambers, such as TEM chambers.

There are several common antennas used for EMC testing, including loop, biconical, log periodic, and horn antennas. Though the type of test equipment used for EMC testing is essential fixed, precompliance testing is often performed with typical bench-top or portable signal generators, spectrum analyzers, software-defined radios (SDR), function generators, and other readily available equipment. Hence, the interconnect used for EMC and Precompliance testing is often standard coaxial cables, connectors, and adapters.

Useful Noise Sources Accessories and Equipment

• Pasternack Phase Stable (VNA) Coaxial Cables
• Pasternack Cable Generic Test Cable Assemblies
• Pasternack Skew Matched Pair Coaxial Cable
• Pasternack Precision Coaxial Adapters
• Pasternack In-series and Between-series Adapters
• Pasternack RF Coaxial Probe