Hello Ed, With the signal @2955 MHz (CF2950MHz)I get similar results. In all Spans I get approximately 65 dBuV which is 10 to 20 dB above noise floor.
Regards, Ken Hall -----Original Message----- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Friday, December 07, 2001 10:25 AM To: 'HALL,KEN (HP-Roseville,ex1)'; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: RE: Stepping receiver, step sizes. Ken: Did you do your test by first setting the receiver to the 2950 MHz signal, and then setting up a symmetrical scan from that reference? For example, if I used a spectrum analyzer to look at 2950 MHz, by setting the CENTER FREQUENCY, and then selected a FREQUENCY SPAN of 4000 MHz with a RESOLUTION BANDWIDTH of 10 MHz, the SA would start its scan at 950 MHz and end at 4950 MHz. The 2950 MHz would be the mid-point sample frequency. Regardless of what SPAN and BANDWIDTH I might choose, the mid-point will always stay the same and always be measured. 100 % probability. Try setting the signal generator to 2955 MHz. Then scan from 2900 MHz to 3000 MHz, using a resolution bandwidth of 1 MHz. BTW, my 8571A system uses an 8566B SA, and that analyzer actually uses an analog swept oscillator. But under software control, it will obey the software requests to look only at the directed frequency with a view of only the selected resolution bandwidth. In the above example, it would see 2949.5 MHz to 2950.5 MHz (3 dB down points), then next see 2959.5 MHz to 2960.5 MHz. Signals between 2950.5 MHz and 2959.5 MHz would be seen anywhere from 3 dB too low to completely missed in the SA noise. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis >-----Original Message----- >From: HALL,KEN (HP-Roseville,ex1) [mailto:ken_h...@hp.com] >Sent: Friday, December 07, 2001 8:09 AM >To: 'John Woodgate'; emc-p...@majordomo.ieee.org >Subject: RE: Stepping receiver, step sizes. > > > >Hello all, > >We typically measure in 500 MHz spans, our spectrum analyzer >has 400 bits so >1.25 MHz/bit. Concerned that we could miss an emission I >perfromed the below >experiment, try it: > >Injected a 2950 MHz signal into EMI Receiver, set for 1MHz >RBW, and measured >it using diffrent Spans > >3 000 MHz 67 dBuV signal, 400 bits 1 MHz RBW >Span [MHz] Amplitude Step/bit [MHz] >10 66 0.025 >500 67 1.25 >1000 67 2.5 >2000 67 5 >3000 66 7.5 >4000 67 10 >6000 67 15 > >What we see is even with the step size 15 times the RBW the >signal is not >lost. > >Regards, > >Ken Hall > > > >-----Original Message----- >From: John Woodgate [mailto:j...@jmwa.demon.co.uk] >Sent: Thursday, December 06, 2001 2:16 PM >To: emc-p...@majordomo.ieee.org >Subject: Re: Stepping receiver, step sizes. > > > >I read in !emc-pstc that Ken Javor <ken.ja...@emccompliance.com> wrote >(in ><20011206195802.LCFL6698.femail7.sdc1.sfba.home.com@[65.11.150.27]>) >about 'Stepping receiver, step sizes.', on Thu, 6 Dec 2001: >>Keeping the step size to one-half the measurement bandwidth >is an accepted >>way of assuring that all possible signals are captured. >Using a step size >>equal to a measurement bandwidth is not quite as good but reasonable. > >In the context of 8, 20 or 80 kHz steps to cover 4 GHz, I think >reasonableness wins. One would be extraordinarily unlucky to lose a >significant signal under those conditions. >-- >Regards, John Woodgate, OOO - Own Opinions Only. >http://www.jmwa.demon.co.uk > >After swimming across the Hellespont, I felt like a Hero. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
