Introduction to EMC Testing

      EMC stands for "Electro Magnetic Compatibility". Electromagnetic compatibility testing refers to the ability of a device or system to work properly in its electromagnetic environment and not cause unbearable electromagnetic interference to anything in the environment. EMC is an important indicator for evaluating product quality.

The main categories of EMC testing are:

1. EMI (Electro-Magnetic Interference) --- Electromagnetic disturbance test
      The purpose of this test is to detect the impact of electromagnetic radiation generated by electrical products on the human body, public power grid and other normally working electrical products.
    
What does EMI testing mainly include?

       • Radiated Emission - radiated disturbance test
       • Conducted Emission - conducted disturbance test
       • Harmonic - harmonic current disturbance test
       • Flicker - voltage change and flicker test

2. EMS (Electro-Magnetic Susceptibility) ---Electromagnetic immunity test
      The purpose of this test is to detect whether the electrical products can work stably in the electromagnetic environment without being affected.

What does EMS testing mainly include?

       •ESD - Electrostatic Disturbance Immunity Test
       •RS - RF Electromagnetic Field Radiation Immunity Test
       •CS - RF Field Induced Conducted Disturbance Immunity Test
       •DIP - Voltage Dips, Short Interruptions and Voltage Variation Immunity Test
       •SURGE - Surge (Impact) Immunity Test
       •EFT - Electrical Fast Transient Pulse Group Immunity Test
       •PFMF - Power Frequency Magnetic Field Immunity Test

Definition of spurious emission: refers to the radiation at discrete frequencies other than the carrier frequency and the sidebands and adjacent channels caused by normal modulation and switching transients when modulated with a standard test signal (i.e., far-end radiation). Spurious emission can be divided into two types: conducted and radiated according to its source.

Conducted spurious: refers to the level power of any discrete signal measured on a 50 ohm load at the antenna connector.
Radiated spurious: stray interference caused by the casing, structure and interconnecting cables of the test equipment. The test conditions are preferably carried out in an anechoic chamber or outdoors.