In message <538f50f1.3090...@ieee.org>, dated Wed, 4 Jun 2014, Richard Nute <ri...@ieee.org> writes:

"Class B limits are amazingly conservative, to which large populations of devices ascribe."


Try using an ordinary AM radio beside a compact fluorescent lamp
as on a beside table.

IS a CFL a 'digital device'?

Yes, well, this is the elephant in the room of radiated emissions. It's called 'separation distance', which is a bit tautological. Measurements made with very low separation are generally not reproducible, which for regulatory purposes is much more important that being realistic.

So standards call for measurements at (mostly) 3 m and 10 m, where reproducibility is (if one is very careful) adequate. At 10 cm, you don't get results, you get options. (;-)
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk
Quid faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society emc-pstc discussion 
list. To post a message to the list, send your e-mail to <emc-p...@ieee.org>

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
Scott Douglas <emcp...@radiusnorth.net>
Mike Cantwell <mcantw...@ieee.org>

For policy questions, send mail to:
Jim Bacher:  <j.bac...@ieee.org>
David Heald: <dhe...@gmail.com>

Reply via email to