Clarification on PCIe add-in card test set-up

Question

We have designed a PCIe add-in card and we plan to do the EMI/EMC test as per the CISPR 32 / EN55032 standard. As we know, the PCIe add-in card will be inserted into the motherboard inside the cabinet.

Since we are going for the Radiated emission test, what should the test set-up look like? Should we have to conduct the test with only PCIe add-in card inserted with bare motherboard without cabinet or a fully closed condition with cabinet? Please clarify.

If you have the reference setup image or link, please share.

Answer 1

I'm not an expert, but I've talked to people who have been through the process of EMC testing and my understanding is you are supposed to test in a representative configuration of how your hardware is intended to be used.

PC motherboards and add-in cards are intended to be used as part of a PC, with the PC case providing the EMI shielding, they are not intended to be used open on a bench and will not pass EMC testing in that configuration.

A big problem when doing some testing is you may have to do some searching to find components for your tests setup that don't cause it to fail. There is very little enforcement that equipment sold actually pass EMC requirements.

This can get crazy sometimes, I recall a story of someone struggling massively to find a HDMI cable that didn't radiate like heck, and eventually ending up buying a PlayStation just to get the bundled cable.