There was a time when Doug's point was very important. I think that time has passed, for a couple of reasons.
1. Most testing is done indoors, so strong ambients are rare. If testing outdoors however, his point is extremely important, except for: 2. Pre-selectors are not what they once were. Originally, a front-end filter protected the mixer and tuned along with the local oscillator. That was even so through the HP85685 add-on pre-selector/pre-amplifier unit for the HP8566. But EMI receivers today tend to have a collection of fixed band-pass filters and some very wide tracking filters, so that the benefit of the pre-selector is not what might be expected. Ken Javor Phone: (256) 650-5261 > From: Doug Smith <[email protected]> > Reply-To: <[email protected]> > Date: Fri, 8 Jan 2016 13:37:13 -0800 > To: <[email protected]> > Subject: Re: [PSES] pre-compliance spectrum analyzer > > Since a spectrum analyzer front end is usually wide open for the entire > bandwidth, a signal out of the range you are looking at could be > overloading the analyzer causing incorrect readings for the signals yor > are looking at. Having a tuned front end is one of the advantages of an > EMC receiver. > > Doug > University of Oxford > Department for Continuing Education > Oxford, Oxfordshire, United Kingdom > -------------------------------------------------- > Doug Smith > P.O. Box 60941 > Boulder City, NV 89006-0941 > TEL/FAX: 702-570-6108/570-6013 > Mobile: 408-858-4528 > Email: [email protected] > Web: http://www.dsmith.org > -------------------------------------------------- > > On Fri, 8 Jan 2016 16:08:23 +0000, Elliott Martinson > <[email protected]> wrote: > http://www.ieee.li/pdf/essay/receiver_v_sa.pdf >> I just noticed you linked to a spectrum analyzer, yet I was talking >> as if we were discussing EMI receivers. There are several key >> differences even though I would have thought they were practically >> the same thing had I not done some research. I noticed the maximum >> sweep time on that spectrum analyzer is 1000s, or 16m40s. So that >> point about it taking hours may seem wrong (at first). But, for good >> measurements on a spectrum analyzer, you have to do only a small >> portion of the total bandwidth at once, because with, say, 30MHz to >> 1GHz frequency range, the measurements would be a whopping 2MHz >> apart! This is bad, because often, problem peaks may be very narrow >> digital ones, which could easily be missed without testing only a >> small portion of the spectrum at once. When that's taken into >> consideration, it may well take hours, but also require more human >> intervention during measurement. Before getting a spectrum analyzer, >> it might be useful to check out the link at the top (unless y! >> ou're already fully aware of the differences). I guess it really >> depends on what you're trying to do. >> >> Elliott Martinson >> EMC Test Technician >> Electronic Theatre Controls >> 3031 N PLEASANT VIEW RD >> MIDDLETON WI 53562-4809 >> [email protected] >> >> >> -----Original Message----- >> From: Elliott Martinson [mailto:[email protected]] >> Sent: Friday, January 08, 2016 9:52 AM >> To: [email protected] >> Subject: Re: [PSES] pre-compliance spectrum analyzer >> >> At my workplace, we've got one of these: >> https://www.rohde-schwarz.com/product/esrp-productstartpage_63493-35077.html >> and it's pretty nice. Especially its huge dictionary of GPIB >> remote-control commands, which makes interfacing with LabVIEW >> convenient. >> R&S makes good products. However, I have never used nor seen the one >> you linked to. >> I noticed no mention anywhere of FFT/time-domain scanning on the page >> or the brochure (it'd be mentioned if it was a feature). That is a >> HUGE weak point IMO, if measurement time is at all important. There >> is no CISPR-Average scanning either, though RMS is probably similar >> enough. Are you trying to find something that's relatively >> inexpensive? Because it may be worth considering the expenses from >> the time costs as well. Time-domain scanning can make something >> that'd take several hours take only a few minutes, or possibly >> seconds (depending on context). If you stick to peak scans, it may >> not be so bad. It'll look noisier than quasi-peak, but that's okay >> since it's better to err on the side of less noise. >> >> -Elliott >> >> -----Original Message----- >> From: Amund Westin [mailto:[email protected]] >> Sent: Friday, January 08, 2016 2:05 AM >> To: [email protected] >> Subject: [PSES] pre-compliance spectrum analyzer >> >> Sorry for incorrect subject ... I'll try again: >> >> ------------------- >> >> Looking for a pre-compliance spectrum analyzer for in-house checking. >> Found this one from R&S. >> http://value.rohde-schwarz.com/vi/value/spectrum-analyzers/hms-spectrum-analy >> zer.html >> >> Anyone who have used this one? >> >> Regards >> >> Amund >> >> - >> ---------------------------------------------------------------- >> 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.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities >> site at http://product-compliance.oc.ieee.org/ can be used for >> graphics (in well-used formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) 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.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities >> site at http://product-compliance.oc.ieee.org/ can be used for >> graphics (in well-used formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) 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.ieee-pses.org/emc-pstc.html >> >> Attachments are not permitted but the IEEE PSES Online Communities >> site at http://product-compliance.oc.ieee.org/ can be used for >> graphics (in well-used formats), large files, etc. >> >> Website: http://www.ieee-pses.org/ >> Instructions: http://www.ieee-pses.org/list.html (including how to >> unsubscribe) >> 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.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used > formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) > 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
