In message <9d04b979323dcd428297dda95108893e0287f...@bb-corp-ex2.corp.cubic.cub>, dated Tue, 8 Sep 2009, "Price, Edward" <[email protected]> writes:
>I recently had a customer say that this method implied that I was using >"rectangular" shape factors, and thus, I should be taking the cube root >of the sum. > >Rectangular? Cube root? It's a subject with a lore of its own. There is extensive treatment in CISPR 16-4-1 to CISPR 16-4-5, but there are difficulties with these, mainly with certain inadequacies in CISPR 16-4-2. 16-4-3 to -5 are probably not relevant for your operations. I don't see anything in 16-4-1 and -2 that permits a cube-root addition, but the statistical distributions of uncertainties is mentioned. Many quantities do have near-rectangular uncertainty distributions, but some do not. Rather than rely on these standards as a source of understanding, it may be better to find a textbook, one that includes a reasonably full mathematical treatment. If that isn't there, some of the explanations are reduced to assertions, which may be counter-intuitive and thus hard to accept. I don't know a good textbook to recommend. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. 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 <[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]>
