Introduction：

When an electronics manufacturer determines that a product has been subjected to EMI electromagnetic interference or has failed an EMC test, we need to know about theReasons for EMI Electromagnetic Interference, also need to know how EMI electromagnetic interference can be eliminated.

We can use a variety of different EMC solutions to solve EMI EMI problems at the source of the electromagnetic field emission or the subject equipment, for example, we simply rotate the subject equipment EUT may be able to make the EUT away from the source of the emission and solve the problem, but the best program is still the EUT redesign and verification test, from the primary stage of research and development to reduce EMI emissions and EMC immunity performance. Here's a look at a few of the common ways we offer to reduce or eliminate EMI electromagnetic interference.

Three common ways to reduce or eliminate EMI electromagnetic interference:

Use filters:

A straightforward way to remove unwanted signals is to filter them out, in which case passive filters work well and they are used in most new equipment to minimize EMI.

Filtering usually starts with an AC line filter to prevent undesirable signals from entering the power supply or power supply circuit, which prevents internal signals from being coupled into the power channel. Filtering is usually used on cables and connectors going in and out of the circuit, and some special connectors can have built-in low-pass filters whose main job is to soften the digital waveform to increase rise and fall times and reduce harmonic generation.

Low voltage analog signals typically require amplification and then filtering to reduce background noise prior to digitization. Signal conditioning usually requires filtering and isolation of the input signal to remove unwanted background noise and to eliminate voltage signals that are well outside the range of the in-line digitizer. Filtering is often used to suppress noise outside a predefined frequency range.

For example, using a CM common mode choke helps reduce EMI through an inductive filter, which blocks (suppresses) unwanted EMI noise while allowing the desired signal to pass through.

Use shielding materials:

On the other hand, the use of shielding materials is the preferred method of suppressing radiation or coupling in a radiation source or in a subject device, and it usually consists of encapsulating the circuitry in a completely sealed enclosure, such as a metal box.

Shielding is critical because it reflects electromagnetic waves back into the enclosure and absorbs waves that are not reflected.

In most cases, if the shielding is not thick enough, small amounts of radiation will eventually penetrate the shielding. Virtually any common metal can be used for shielding (e.g., copper, steel, aluminum).

Design of a new grounding system:

Grounding is the establishment of a conductive path between the electrical or electronic components of a system and a reference point or plane of reference ground, and may also refer to an electrical connection to ground.

  • In order to achieve the least amount of EMI electromagnetic interference, the following best practices for PCB grounding system design need to be kept in mind:
  • Keep leads away from internal circuits or other components and ground them as short as possible to minimize inductance.
  • Best results are obtained by using multiple grounding points on large grounding layers.
  • If the ground loop voltage cannot be controlled in any other way, attempt to isolate the circuit from ground.
  • Keep separate grounds for the analog and digital circuits-you can combine them later at one point in the combine.

Utilizing any of these methods will not only help you reduce EMI electromagnetic interference, but will also help ensure that your equipment is less susceptible to future interference and help reduce radiation.

Optimized PCB design

Optimizing PCB electronic design covers all the techniques used by engineers from the introduction of a new product to the manufacturing process.

Hardware development engineers should give due consideration to power integrity, signal integrity and electromagnetic capability (EMC) performance.

  • Power Integrity(PI) checks that the required voltage and current are met from source to destination. Today, power integrity plays a critical role in the success or failure of new electronic products.
  • signal integrity(SI) is a set of measures of electrical signal quality.

In terms of signal integrity, engineers try to match the impedance of an alignment to some value, typically 50 Ω. To achieve good power integrity, they want the power distribution network (PDN) to have the lowest possible impedance.

Meeting EMC requirements is critical to bringing any electronic product to market. Engineers need to consider EMC as early as possible to avoid redesigns, delays and increased project costs.

EMC testing is about meeting standards and EMC behavior in all design phases. With the increase in electronic devices being introduced every day, the potential for devices to interfere with each other is high.

As an industry leader, we eliminate electromagnetic interference by providing complete solutions that include EMC testing and EMC rectification technical solutions, please contact us for more information.