Getting To Know About Electromagnetic Compatibility Testing

Can you imagine when you are using a smartwatch in the office then your smartwatch doesn’t function as it should be when your desk near a router. All your recorded healthy moves are not readable due to a highly interference from nearby working devices. This situation can describe how important the EMC testing takes its significant role to ensure all wireless products can work without causing an electromagnetic interference, these products should operate without disturbing each other and more importantly they can tolerate to the external disturbances from electromagnetic disturbances.
In this essay, I would like to introduce you the EMC test items, Testing Environments, DUT preparation, and Testing Procedures that are usually performed in the products’ type approval or homologation process.

1. Testing Items

• Radiated Emissions Testing
  This EMC test item measures the level of electromagnetic emission and interference emitted from a device via air. This test will use some specific limit from any EMC test standards i.e CISPR32 or EN301489. It ensures the device doesn’t radiate the interference or emission too much into the surrounding environment.
  This test is divided in to 2 ranges of frequency range starting from 30 MHz ~ 1 GHz and 1 GHz ~ 6 GHz.
• Conducted Emissions Testing
  This EMC test measures the electromagnetic emission and interference emitted via cables or power lines, and any telecommunication port such as RJ45, RJ11, etc to ensure the device not causing any harmful interference back into the electrical grid or the telecommunication port.
  This test is performed in at the frequency range 150 kHz ~ 30 MHz.

2. Testing Environments

• Anechoic Chamber
  For radiated emission testing, It is a designed room or chamber to reduce any interference and reflections. This chamber is also equipped with materials that absorb the signals to prevent them from bouncing back onto the DUT, thus providing a more accurate measurement of its emissions and reception. And it is also equipped with movable antenna receivers, Line Impedance Stabilization Network (LISN), Impedance Stabilization Network (ISN) and spinnable floor (Turntable).
• Control Room
  It is a room designed with some electric controllers to move the antennas inside the chambers, to move the spinnable floor (turntable), and this room is where the test receiver units are placed.

3. Preparing the Device Under Test (DUT)

Performing an EMC test has several steps to ensure that a device meets electromagnetic compatibility requirements. The process may vary depending on the type of test being conducted (e.g., radiated emissions, conducted emissions). In general, the procedure typically follows these steps

• Device Setup: The device is usually the same as normal products which are going to be sold in the market, or it also could be some special device designed with some operational mode from the manufacturer.
• Connection to Power Supply: The power supply may also vary from the original product, it may use different power rating to investigate and measure the lowest and highest peak of the emission and interference result.
• DUT and Environment Setup: The device should be tested in a controlled environment, the device can work as standalone or the device may use some additional supporting equipment or peripherals.

4. Testing Procedures

• Select Test Standards
  Choose the appropriate EMC test standards (such as CISPR32, or EN301489), based on the product’s industry and the regulations in your targeted market. These standards specify the acceptable limits for emissions and immunity levels.

• Radiated Emissions:
  – Place the DUT on the spinnable floor (turntable) in the chamber.
  – Choose the appropriate antenna receiver to measure the electromagnetic radiation from the device at specific distance and angles.
  – Measure at specific points around the DUT to capture the emissions from different directions.
• Conducted Emissions:
  – Place the DUT on the spinnable floor (turntable) in the chamber.
  – Connect LISN to measure the noise or signals conducted through the power lines
  – Connect ISN to measure the noise or signals conducted through the telecommunication port.

5. Conclusion

EMC testing is very important to ensuring that electronic devices don’t cause unwanted interference and can function properly in environments with electromagnetic disturbances. However, with the right setup and procedures in place, it is possible to ensure a device’s compliance with EMC requirements and improve its performance in the field. If you still need more detailed information, please kindly visit us on https://www.dimulti.co.id/contact/