Whoa Ken! I'm not advocating any test techniques here.
I am in total agreement with 461F. Always have been. Sent from my iPhone On May 13, 2009, at 1:55 PM, Ken Javor <[email protected]> wrote: > MIL-STD-461F deals with this just the opposite of what you say - > increases > the sweep speed and puts analyzer in max or peak hold mode. The > total time > taking the multiple fast sweeps must be at least as long as using the > default sweep times for a single sweep. The idea is to specifically > catch > signals which are time synchronized, not frequency stable, relative > to the > analyzer bandwidth. > > Ken Javor > > Phone: (256) 650-5261 > > >> From: "Haynes, Tim (SELEX GALILEO, UK)" <[email protected]> >> Date: Wed, 13 May 2009 17:03:52 +0100 >> To: Derek Walton <[email protected]>, John Woodgate <[email protected] >> > >> Cc: <[email protected]> >> Conversation: Dimmer Switch >> Subject: RE: Dimmer Switch >> >> Hi All, >> >> I think that I would describe it as the following, >> >> Every t=1/50 seconds current flows and this has a fast rise time. The >> net effect is a comb occurring in the frequency domain every 50Hz, >> however, this comb only appears every 1/50 (=20)ms. >> >> If the sweep is, say 20ms for the whole screen - then one, possibly >> 2 of >> these time domain events will show on the screen. >> >> In order to correctly display this type of signal, the sweep time >> should >> be slowed and the frequency range adjusted until each 50Hz element is >> displayed. >> >> A quick answer to something that could take a lot of explaining - may >> mean that there are limitations to the answer! >> >> Regards >> Tim >> (Off home now) >> >> ************************ >> >> Tim Haynes A1N10 >> >> Electromagnetic Engineering Specialist >> >> SELEX Sensors and Airborne Systems >> >> 300 Capability Green >> >> Luton LU1 3PG >> >> ( Tel : +44 (0)1582 886239 >> >> 7 Fax : +44 (0)1582 795863 >> >> ) Mob : +44 (0)7703 559 310 >> >> * E-mail : [email protected] >> >> P Please consider the environment before printing this email. >> >> >> >> There are 10 types of people in the world-those who understand binary >> and those who don't. J. Paxman >> >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On Behalf Of Derek >> Walton >> Sent: 13 May 2009 16:04 >> To: John Woodgate >> Cc: [email protected] >> Subject: Re: Dimmer Switch >> >> *** WARNING *** >> >> This message has originated outside your organisation, >> either from an external partner or the Global Internet. >> Keep this in mind if you answer this message. >> >> >> I think you are missing th point John, I'm not saying harmonics >> aren't >> there: I've stressed harmonic rich as much as I can..... >> >> It's all down to what you see on the display of the SA, and thats >> sweep >> time dependent. Ken describes that well. >> >> The lines that appear on the display are spaced on sweep time not >> frequency. >> >> It would be useful to show graphs on the group! >> >> Cheers, >> >> Derek. >> >> >> John Woodgate wrote: >>> In message <c630442d.4265c%[email protected]>, dated >>> Wed, 13 >> >>> May 2009, Ken Javor <[email protected]> writes: >>> >>>> Have to admit to being confused by the Woodgate-Walton discussion. >>>> The way I see it, the dimmer switch is indeed generating a harmonic >>>> rich signal. The spectrum analyzer, due to the required EMC >>>> bandwidths, doesn't show each individual harmonic - the bandwidth >>>> is >>>> wider than the harmonic spacing. Therefore the dimmer switch is >>>> creating what appears to be broadband noise, as long as your >>>> reference point is audio frequency bandwidths necessary for radio >>>> communications, and by extension EMI measurements. >>> >>> I agree. The harmonics are there, whatever you can or can't see on >>> the >> >>> SA display. >> >> - >> ---------------------------------------------------------------- >> This message is from the IEEE Product Safety Engineering Society >> emc-pstc discussion list. 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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]> > > - > ---------------------------------------------------------------- > 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]> - 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]>
