Maybe it's a silly question but I couldn't find any useful info about this. Sorry for that.
I've been asked to design a 72-to-24VDC/6A converter for railway vehicles. I designed one and it works perfect. But our customer wants that the converter should pass railway EMC (i.e. both conducted and radiated emissions defined under EN50121-3-2) tests.
We have a small measurement laboratory equipped with Rohde&Schwarz measurement devices. We perform some pre-measurements on the products so that we can see their performances and make necessary modifications before sending them to accredited companies for actual testing and certificating process. For now, we can only measure conducted emissions in our small lab. Anyway, I performed some measurements in our small lab and made some modifications on the circuit to have it finalized.
After finalizing the test sample, I showed the pre-measurement results to my executives and one of them told me that if I can have the product passed the conducted emission pre-test according to radiated emission limits then it can pass radiated emission test as well (NOTE: RE limits are lower than CE's and as I stated above, we can only measure conducted emissions). When I ask him to explain why, he only says that our other products could passed RE test when they pass CE as well. But this is not an answer for me.
Sorry for the looong story, and finally my question is: How can it be? As you can guess, CE can be thought as the emission conducted via supply (or other signalling, control etc.) cables to other devices and/or battery and it's measured directly from the cable via a spectrum analyzer but RE is defined as the emission radiated by the device itself via its case (or not, doesn't matter) and it's measured via a 10m-distant-antenna. So, is it possible to define a substantial relationship between conducted and radiated emission?