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What Is EMC? What Is EMC Testing? Standards, Compliance, Certifications, & More
Every electronic device generates electromagnetic radiation. It’s a byproduct of the electric current passing through a circuit. This energy is on the low-frequency, non-ionizing end of the electromagnetic spectrum. Unlike the ionizing radiation generated by the sun, X-ray machines, and radioactive elements, non-ionizing radiation is not harmful to living cells.
However, an electronic device's electromagnetic fields (EMFs) can harm other devices around it. That’s why devices must meet specific regulatory requirements for electromagnetic compatibility (EMC).
What Is EMC?
EMC stands for “electromagnetic compatibility.” It examines a device’s ability to 1. function as expected in its electromagnetic environment and 2. not affect the other equipment in the environment’s ability to operate correctly.
In other words, EMC examines how well a device functions in the presence of electromagnetic energy and how much electromagnetic energy it produces that could potentially harm other devices in the environment. Electromagnetic compatibility can be achieved by limiting the unintentional creation and reception of potentially harmful electromagnetic energy (like EMI).
Difference Between EMI and EMC
“EMI” and “EMC” are often used interchangeably in device testing. Although related, they describe different things. EMI stands for “electromagnetic interference.” It describes electromagnetic energy that interferes with electronic devices.
Radio frequency interference is among the most common sources of interference seen today. Radio frequency interference (RFI) occurs when the electromagnetic energy in question is on the radio frequency spectrum.
EMC seeks to mitigate the impact of EMI through effective shielding of susceptible equipment. Mitigating electromagnetic interference (EMI) leads to electromagnetic compatibility (EMC).
What Is EMC Testing, and Why Is It Important?
EMC testing determines how well a device can operate in the presence of electromagnetic energy in its environment and how much electromagnetic energy the device itself generates that could cause electromagnetic interference for other devices in its environment.
EMC testing focuses on two main issues. Emissions suppression and susceptibility hardening (mitigation).
EMC Emissions Testing
EMC emissions testing examines the amount of electromagnetic energy a device produces that could cause electromagnetic interference for other devices in its environment. It falls into two main categories.
- Radiated emissions - Measures the electromagnetic disturbance a device creates itself.
- Conducted emissions - Measures the amount of internal electromagnetic energy which can travel from this device via a conductor (typically wires) that could cause EMI on other devices or systems in the environment.
EMC Immunity and Susceptibility Testing
EMC immunity and susceptibility testing examine how well a device functions in the presence of outside electromagnetic energy. Similar to emissions testing, immunity and susceptibility testing fall into two main categories.
- Radiated immunity/susceptibility - Measures how well a device will perform when exposed to electromagnetic energy it will encounter in its common environment.
- Conducted immunity/susceptibility - Measures how a piece of equipment responds to electromagnetic energy generated from another source but is conducted (typically along a cable) to the device under test.
EMC testing labs and operators also consider coupling. This is the mechanism or pathway through which emitted interference reaches the impacted device.
EMC testing is essential because the generation of electromagnetic energy is ubiquitous throughout modern electronic devices. Any device that uses digital techniques and has timing pulses greater than 9000 cycles per second is a source of unintentional radiation. That includes every device with a microprocessor. Intentional radiation is generated by alarm systems, cordless phones, remote controls, and other devices that transmit radio signals.
EMC Compliance, Standards, and Certification
Virtually every country requires the testing and certification of devices to ensure they meet EMC standards. In the U.S., those standards are regulated by the Federal Communications Commission (FCC) according to FCC Rules and Regulations Title 47, Part 15.
EMC Class A vs. EMC Class B
Regulated devices generally fall into two categories. Devices for commercial or industrial use fall into Class A, and devices for consumer use fall into Class B. Class B devices have more stringent limitations on EMC than Class A devices. There are exemptions for appliances, automobiles, industrial, medical and scientific equipment, and a few other categories of devices.
United States vs. International EMC Standards
Regulated products sold in the U.S must be tested according to the procedures outlined in ANSI Standard C63.4. The objective is to ensure that they meet standards for RF emissions in the 9kHz to 40GHz frequency range. The rules may require a declaration of conformity, verification, or certification, depending on the type of device. The FCC regulates only emissions, not susceptibility/immunity of devices under test.
The E.U. regulates both emissions and susceptibility/immunity according to IEC 61000 standards. EMC Directive 2004/108/EC states that equipment must be tested for compliance and labeled accordingly. Many other countries require compliance with either the FCC or E.U. standards, although some countries have developed their own similar regulations. In some cases, testing must be performed by a certified lab.
How Enconnex Can Help with EMC and EMI Testing
The Enconnex DevShield and DevRack lines of real device testing racks and cabinets are designed to facilitate testing under various conditions. While they won’t provide the measurements needed for formal EMC testing, verification, and certification, they are useful tools for determining how devices perform under real-world conditions.
What Are DevShield and DevRack?
DevShield cabinets are constructed from aerospace-grade shielded aluminum with copper-nickel gaskets shielding all the seams and penetrations of the cabinet for maximum protection. They provide 85dB of attenuation for frequencies ranging from 1MHz to 10 GHz (our 5G version provides 75dB at 1MHz-40GHz). With DevShield, product testing teams can place a device in the cabinet to see if it impacts the performance of other common devices within the cabinet. DevRack products are unshielded. They allow testing teams to see how a device performs in the presence of everyday EMI.
Both lines of products are designed to make real device testing more efficient. They enable real device cloud configurations and provide a better alternative vs. emulators and simulators. Hundreds of devices can be housed within the footprint of a traditional data center rack, with pull-out shelves for easy device access. Powerful integrated fans help dissipate heat, while cable management solutions, wireless access point mounting brackets, and other accessories keep the environment neat and organized.
What is DefenseShield?
Our DevShield product was inspired by our DefenseShield product. DefenseShield offers the same level of shielding and the same form but is designed for cybersecurity applications. It uses its EMI shielding and associated EMC environment to create a secure environment where data is protected from threats such as side-channel attacks where hackers decode RF signals emanating from equipment.
Whether you need to protect your information from threats such as side-channel attacks or test devices for EMC, Enconnex is your source. Contact our experienced team for expert guidance on setting up your lab environment.
Posted by Alex Zhang on July 26, 2022
Alex has 10+ years of experience working in the data center and material science industries. He currently serves as product manager at Enconnex for our real device testing and RF shielded product lines. Previously, he managed our sheet metal products. He has his MSEE degree from Northwest Polytechnic University and holds numerous professional certifications.