I would be careful about using the Uncertainty Calculator freeware tool. It was written in March 1997 prior to the release of CISPR16-4-2:2003 and EN55016-4-2:2004. Please note that these later standards have mandated extra quantities to consider in emissions testing that forces a different measurement uncertainty for horizontal polarity versus vertical polarity measurements.
The math doesn't change for summing the squared uncertainties of each input quantity, square rooting the sum, and then multiplying by 2 for an expanded uncertainty. Just be aware that you may need to add extra quantities and create more expanded measurement uncertainty results. Of course, that can also be done on a simple spreadsheet. The EN55016-4-2:2004 (CISPR16-4-2:2003) is pretty straight forward on the math and the quantities to be included, but it is not very helpful on finding real values for each of those quantities. Section A.5 does attempt to give some description on what the values of some quantities should be based on the type of measurement equipment is used. Still, I agree that it would be helpful if a guide was created to help implement the standard including how to measure some of the values as opposed to relying on the worst-case values listed in the standard.. Monrad L. Monsen Worldwide Compliance Officer Sun Microsystems [email protected] 303.272.9612 Office John Woodgate wrote on 9/9/2009 10:47 AM: In message <[email protected]> <mailto:[email protected]> , dated Wed, 9 Sep 2009, "Kunde, Brian" <[email protected]> <mailto:[email protected]> writes: It should be simple. As Einstein said, 'Things should be a simple as possible, but no simpler.'. Uncertainty simply ISN'T simple, unless you will put up with 'worst-worst-worst' case approximations that may be very tough to handle. An example for Radiated Emissions, here are the contributors, here is how you obtain those values, here are the factors for each, do some math on a spreadsheet and DONE. Look at: http://www.callabmag.com/freeware.html Uncertainty calculator 3.2 has been recommended to me by a REAL expert on the subject. - 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
