Common mode chokes for signal lines and comms lines

[Faringdon]

Hi,
For helping to pass radiated emissions to EN55032...
When you've got comms and signal lines exiting/entering a PCB via connectors, which is your favourite family of common mode chokes?
I am thinking of something with NiZn ferrite, or nanocrystalline.

[Terry Bites]

It depends on your current and voltage rating and the frequency range you'd like to supress. I usually go to coilcraft or first because of their useful calcultion tools. But then I'm not in mass production.
Its always a bit wierd that makers of these devices specify them with 50R source and load- which is not very likely!
You need to understand your sources of EMC before you can squash them. There's is no easy fix.