Dear Muriel Separating CM from DM at the output of a LISN was covered by Michel Mardiguian and Joel Raimbourg in a paper they presented at the IEEE EMC Symposium held in Seattle in August 1999, titled: "An alternate, complementary method for characterising EMI filters" (Volume 2 of the Symposium Record, pages 882-886).
They describe using a 'CM/DM splitter transformer' which is available from AEMC, a French company about whom I have no further details. But it does not seem difficult to make your own 'splitter' transformer as it appears to be a simple type of transformer. I referred to this paper and redrew their figure for the transformer in the article I wrote with Tim Williams for the EMC + Compliance Journal, April 2001, titled: "EMC Testing Part 2 -Conducted emissions" (pages 22 - 32, available on-line in their Archive section at www.compliance-club.com). Regards, Keith Armstrong www.cherryclough.com In a message dated 05/02/02 02:44:29 GMT Standard Time, [email protected] writes: > Subj:Conducted noise emission diagnosis device > Date:05/02/02 02:44:29 GMT Standard Time > From: [email protected] (Muriel Bittencourt de Liz) > Sender: [email protected] > Reply-to: <A HREF="mailto:[email protected]";>[email protected]</A> (Muriel > Bittencourt de Liz) > To: [email protected] (EMC-PSTC) > > Hello Group, > > > I am looking for a device that will differentiate the dominant component > (either > common-mode or differential-mode current) in the total conducted noise > emission > current of a product measuring through its' power cord using a LISN. > > > This device can be called "common/differential mode current separator". In > conducted > noise emission measurement, both common-mode and differential mode noise > current are measured by LISN and the LISN can't tell which mode is the > dominant > current. > > > I came across a paper by Clayton Paul and Keith Hardin which explain the > usefulness of a separator like this that would identified the dominant > current > from the total current. Hence, the correct capacitor value(either X-caps or > Y-caps) can be changed accordingly so to reduce the overall conducted noise. > The book by Clayton Paul "Introduction to Eletromagnetic Compatibility" has > also mention about this device. > > > I have contacted a few persons trying to look for the person who have > actually > built this separator himself and I am also looking for any vendor who have > this > product for sale. So far, my effort has yield no results. > > > Can anybody point me to the right person so that i can try to built this > separator myself. Any other suggestion and comments are greatly appreciated. > > > Best Regards, > > ************************************************************** > > Muriel Bittencourt de Liz > > Ph.D. Student > > Federal University at Santa Catarina > > Florianópolis, SC > > Brazil >
