Category:PCB Electromagnetic Interference

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Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.Shortly, EMI is an electronic noise that disturbs the cable signal and reduces signal integrity.

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What is Electromagnetic interference (EMI)? Reply 2017-02-15 17:54:19


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What is EMI? Electromagnetic interference (EMI) is an electronic noise that disturbs the cable signal and reduces signal integrity. EMI is usually generated by electromagnetic radiation sources such as motors and machines.

What is the cause of electromagnetic interference?

We often heard of electromagnetic interference, but how is the electromagnetic interference generated? In fact, the factors of interference are complicated. There are two modes of interference, namely, differential mode and common mode. Differential-mode interference refers to interference between two transmitted as round-trip wires. Common-mode interference refers that except the two wires, there is still an earth wire.

The types of electromagnetic interference

Electromagnetic interference is divided into conducted interference and radiation interference. Conducted interference refers that the signal on an electrical network is coupled (interfered) to another electrical network through a conductive medium. Radiation interference refers that the interference source couples (interferes) its signal to another electrical network through the space. In high-speed PCB and system design, high-frequency signal lines, integrated circuit pins, all kinds of connectors may become a radiation source, which can emit electromagnetic waves and affect the normal work of other systems or other subsystems within the system. 

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Jeff Hanenkrat

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