Could you define how precise? What is your acceptance criteria for the modulation dept? Let's say for basic 80 % AM modulation. Is your tolerance 0.1 % or between 60 % to 90 % is good enough. There is more than a dB peak difference in the signal for 60 % AM and 80 % AM modulations. You won't realize the difference with a field probe in radiated immunity tests with modulated signal. (Simple math; 20*Log(1.6/1.8) = -1.02 dB) It seems not very insignificant to me
Another case; If you are using 6 meter cable for radiated emission at 10 GHz, your cable characterization uncertainty is more than 1.5 dB even with a quite high grade cable (Experimental measurements). Check the cable vswr figures in their specs measured in ideal conditions. Even a simple cable is a significant uncertainty contributor. Your measurement antenna is not exactly 50 Ohm at 10 GHz also. Site imperfection is another story. Those figures are not accounted for in the MIL-STD-461 RE102 verification. Everything seems to be very good when you terminate the measurement cable with a signal generator (50 ohm) output. I don't agree with this <quote> an ultimate "proof-of-the-pudding," </quote> You can use all your engineering skills for the tests but you have to quantify your risk using type B measurement uncertainty analysis and do the Type A if you can afford to see where you stand. As Mr. Gremmen said " MU is not difficult" No need to be afraid, OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:[email protected] web: http://www.ntscorp.com/about/locations From: [email protected] [mailto:[email protected]] On Behalf Of Ken Javor Sent: Wednesday, August 11, 2010 7:55 AM To: Untitled Subject: Re: Calibration supplier for signal generator with pulse modulation Precisely. Ken Javor Phone: (256) 650-5261 > From: Cortland Richmond <[email protected]> > Reply-To: <[email protected]> > Date: Wed, 11 Aug 2010 08:27:34 -0400 > To: emc-pstc <[email protected]> > Subject: re: Calibration supplier for signal generator with pulse modulation > > Not quite what you need to know but I've used signal taps or directional > couplers with a 'scope to watch the RF waveform and set modulation depth, > and a calibrated counter, or even a receiver or analyzer will for > frequency. One always has recourse to calibrated devices to monitor > another, uncalibrated one. It's a good idea anyway! If a detector must be > used whose linearity is unknown, one can use calibrated attenuators to find > out. > > > Cortland Richmond > KA5S > > >> [Original Message] >> From: Wendy Nya <[email protected]> >> To: <[email protected]> >> Date: 8/10/2010 4:23:29 AM >> Subject: Calibration supplier for signal generator with pulse modulation >> >> Dear All, >> >> I am looking for a calibration supplier that can provide accredited > service for >> AR SG6000. It has built-in pulse modulation option (for Radiated Immunity > use). >> >> By the way - Is anyone using this model? It seems to be OEM from Agilent > (it >> came in an agilent box) but the equipment is marked AR >> and works with Agilent N5181A driver. Agilent is saying that it is not > able to >> provide accredited calibration service for this model. >> >> Thanks & Regards, >> Wendy Nya > > - > ---------------------------------------------------------------- > 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]> - 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]>
