I am just now gotten very interest on this subject. I think you mention a key factor: antenna factor. The SA noise floor unit is dBm. After you have added the antenna factor the unit is dBuV/m. Everything else being perfect, zero loss, 0 dBi antenna gain across frequency, etc., the antanna factor is still be highly frequency depedent. I think: AF = 20log(MHz) - 29.8. Therefore the flat SA noise floor in dBm will be traslated into a curve in dBuV/m.
Regards, Alfred On February 23, 2016 4:42:47 PM PST, "McDiarmid, Ralph" <ralph.mcdiar...@schneider-electric.com> wrote: >I would like to explain to a colleague why the noise floor on a SA does > >not look flat as it sweeps across a given frequency range after antenna > >factors, cable factors, external gain and external attenuation are >programmed into its display function. > >I think it breaks down to these fundamental points: > >1. the SA receiver has noise in its attenuator, mixer and filter >circuits >(say -80 dBm, and maybe flat within a limited frequency range) >2. the external amplifier has some noise too, but its gain lowers the >noise floor created by #1 (also flat within a limited frequency range) >3. the cables have losses which are frequency dependant, and those can >be >entered as loss factors into the SA (shapes the noise floor a little >and >those losses raise the noise floor) >4. the antenna has a gain which is frequency dependant with several dB >of >hills and valleys across its usable frequency range (that really shapes > >the noise floor more than 1, 2 or 3 above) >5. noise floor shape caused by #4 is the mirror image of the antenna >factor vs frequency > >Is that a decent summary? >. >Ralph McDiarmid >Compliance Engineering >Residential/Commercial >Solar Business >Schneider Electric >D +1 (604) 422 2622 x62622 >E ralph.mcdiar...@schneider-electric.com >3700 Gilmore Way >Burnaby >BC >Canada > >- >---------------------------------------------------------------- >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.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 <sdoug...@ieee.org> >Mike Cantwell <mcantw...@ieee.org> > >For policy questions, send mail to: >Jim Bacher: <j.bac...@ieee.org> >David Heald: <dhe...@gmail.com> -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. - ---------------------------------------------------------------- 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.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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
