electromagnetic compatibility noise

When an electronic device or product is in operation, due to a variety of factors, the product's voltages, currents, signals, etc. will contain many unwanted noise components, many of which may be the cause of product malfunctions or degradation of performance, which is different from the ideal situation expected by hardware development and designers. These noises are then defined as electromagnetic compatibility noise, also called EMC noise.

EMC noise type:

There are two types of EMC noise: natural noise such as lightning strikes and static electricity; and artificial noise such as motors and fluorescent lights. Some of these emit electromagnetic waves, also called intentional emissions, such as communication base stations and broadcasting towers. To obtain the real source of noise, we need to choose different test methods to test whether the product generates these noises; and also to test whether the product works properly under the influence of these noises, which is in line with the basic test requirements of electromagnetic compatibility. Two types of noise are shown in the table below:

The way EMC noise affects the product:

EMC noise affects products in different ways, which are roughly categorized as follows:

transmitted noise

Conducted noise propagates through wire or circuit board patterns, and when a peripheral device's power or signal line is close to the line (wire or PCB) through which the noise current flows, the noise generates induced conducted noise on nearby cables through electromagnetic induction or electrostatic induction.

radiated noise

There are many components on the PCB that can be used as antennas, and these antennas can either receive or transmit noise.

summarize

Having learned the above basics about EMC noise, we can move on to learning how to test for these EMC noises.

About the concept of EMC electromagnetic compatibility and EMC test system introduction