Does 'ambient scans' mean a measurement done on the spectrum with the EUT turned off or not present? Would an ambient CW or modulated signal affect measurement uncertainty? I suppose it would, because it cannot simply be subtracted from the EUT spectrum. _____________________________________________________________________________________
Ralph McDiarmid | Schneider Electric | Renewable Energies Business | CANADA | Regulatory Engineer From: "ce-test, qualified testing bv - Gert Gremmen" <g.grem...@cetest.nl> To: EMC-PSTC@LISTSERV.IEEE.ORG List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 08/10/2010 12:51 PM Subject: Re: [PSES] Calibration supplier for signal generator with pulse modulation ________________________________ >>I seem to recall that the military wants to see ambient scans with at >>least 6dB under any limit. Kind of a inside out measurement >>uncertainty?. >Yes, it's a sort of insurance against a 6 dB favourable error. But the >point is that it's FAR easier to cope with in practice, and it may well >give a more dependable assurance of compliance than a complex >uncertainty assessment. Well you can call this a 6dB trick but in fact is the implementation into the daily use of MU. Just that it has been calculated by someone else, and assumed to be true for every test set up. MU is not difficult, the calculations do not involve more then: 1. characterization of the fault contributor, result into division factor 2. square the obtained value 3. do this for all contributions 4. add up all factors 5. take the root and multiply by 2 = total expanded uncertainty That’s all there is. The tricky part is the characterization in type of error. Google for probability distribution and type A or type B uncertainty if you want to learn. Gert Gremmen ce-testm qualified testing ________________________________________________________________________ This email has been scanned for SPAM content and Viruses by the MessageLabs Email Security System. ________________________________________________________________________ - 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 <mailto:emc-p...@ieee.org> > All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc <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/ <http://www.ieee-pses.org/> Instructions: http://listserv.ieee.org/request/user-guide.html <http://listserv.ieee.org/request/user-guide.html> List rules: http://www.ieee-pses.org/listrules.html <http://www.ieee-pses.org/listrules.html> For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com <mailto:emcp...@socal.rr.com> > Mike Cantwell <mcantw...@ieee.org <mailto:mcantw...@ieee.org> > For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org <mailto:j.bac...@ieee.org> > David Heald <dhe...@gmail.com <mailto:dhe...@gmail.com> > - 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.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 <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
