EMC/EMI

Far-field Emissions from PCB Cavities_thumb

Far-field Emissions from PCB Cavities

In high-speed circuit designs, power integrity (PI) and electromagnetic interference (EMI) are connected together. When the edge of the cavity created by power (PWR) and ground (GND) planes in PCBs radiates, the peak frequencies in the emissions are the same as the peak frequencies in the cavity self-impedance.


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Avoid These Two Artifacts When Measuring SMPS Power Rails

Switch-mode power supplies (SMPS) are commonly used DC-to-DC converters in many electronic components. By their nature, they can generate a lot of radiated emissions. Unless care is taken, it is difficult to separate what is the actual voltage on the power rail and what is an artifact due to the way we probe the circuit. The project outlined here shows how to avoid EMI pick-up and cable reflection noise.


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EMC Blog_

Shielding and Filtering Are Not Independent of One Another

I have lost count of the number of times I have been asked to fix an EMC problem, only to find that a shielding box has been designed or purchased to provide XdB up to fMAX. Or a filter has been designed or purchased with a similar specification, but to reduce cost the filter has been mounted on a printed circuit board (PCB) inside the box, with a cable from it entering or exiting the box through a plain connector.


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