> -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf > Of John Woodgate > Sent: Thursday, December 04, 2008 7:08 AM > To: emc-p...@ieee.org > Subject: Re: Radiated emission - time at each frequency > > In message > <9d04b979323dcd428297dda95108893e0120c...@bb-corp-ex2.corp.cubic.cub>, > dated Thu, 4 Dec 2008, "Price, Edward" <ed.pr...@cubic.com> writes: > > > >The simplistic answer is that you should dwell at a frequency long > >enough for the detector to respond to any emission that occurs. > > It's a base rumour that some regulatory test houses dwell > until they get a 'FAIL'. (;-) > > Seriously, it's a very difficult question to answer. If the > product has some sort of cyclic behaviour within a short > time, waiting some tens of milliseconds may be acceptable, > but what about a washing machine with a 150 minute cycle? > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
I think the conservative way to approach that would be to see if you could eliminate the time delays in a cycle without affecting the events of the cycle. For instance, you could rig the "wash" cycle to turn on, then off again in a second or two, eliminating 5 minutes of boring motor running. You could rig a water level detector to trip without the tub actually filling, etc. You might also do an analysis to show that certain functions are redundant or duplicative, for instance, the spin cycle may consist of a motor start/stop operation identical to a spin cycle, so you could eliminate one of the whole cycles. Some of my test setups have used multiple strings or cords so that I can yank a cord to fake some mechanical sensor in an EUT into thinking it is ready to move on to the next function. Regards, Ed Price ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty - 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...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
