Are you saying that the results of a 'tuning' style measurement sequence are different than a 'stepping' style measurement sequence?
On a slightly different note: The HP 8591EM has the capability of log frequency sweeps without the use of an external controller. I looked at the X-axis output drive waveform once, and was surprised to see that it was comprised of 7 or 8 ramp waveforms chained together, of different durations. I assume it was several linear sweeps chained together, although I never checked. On Mon, 10 Dec 2001 11:48:12 -0800, "Price, Ed" <[email protected]> wrote: >Ken and I have been talking this over off-line, and it seems like an >important thing to note is that the HP / Agilent spectrum analyzers tune >over a measurement range by continuously sweeping their local oscillator. >Setting a resolution bandwidth and a span width does not mean that the >analyzer will tune in discreet hops. Even under external HP software >control, the analyzer firmware still does (perhaps a series of) analog >sweeps. > >OTOH, if you use your own software, specify a resolution bandwidth, and then >send a series of "tune, measure, tune,..." commands, then you can miss >emissions between the skirts of the passbands if your step size is too >large. > >You have to understand how your receiver or analyzer actually covers a >frequency range. > >Regards, > >Ed > > >Ed Price >[email protected] >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:[email protected]] >>Sent: Friday, December 07, 2001 8:38 AM >>To: 'Pettit, Ghery'; HALL,KEN (HP-Roseville,ex1); 'John Woodgate'; >>[email protected] >>Subject: RE: Stepping receiver, step sizes. >> >> >> >>Hello Gary and all, >> >>The point is do an experiment with your Stepping receiver. >> >>Ken >> >>-----Original Message----- >>From: Pettit, Ghery [mailto:[email protected]] >>Sent: Friday, December 07, 2001 8:36 AM >>To: 'HALL,KEN (HP-Roseville,ex1)'; 'John Woodgate'; >>[email protected] >>Subject: RE: Stepping receiver, step sizes. >> >> >>Ken, >> >>A spectrum analyzer sweeps through a range of frequencies. >>The resolution >>of the display merely impacts the accuracy of the frequency >>determination >>for a signal when digitized and sent to a computer over the >>bus. Each point >>on the display simply shows the highest level obtained in the >>range covered >>by that point. This is different than step tuning a receiver. >> >>Or am I missing something? >> >>Ghery Pettit >>Intel >> >>-----Original Message----- >>From: HALL,KEN (HP-Roseville,ex1) [mailto:[email protected]] >>Sent: Friday, December 07, 2001 8:09 AM >>To: 'John Woodgate'; [email protected] >>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:[email protected]] >>Sent: Thursday, December 06, 2001 2:16 PM >>To: [email protected] >>Subject: Re: Stepping receiver, step sizes. >> >> >> >>I read in !emc-pstc that Ken Javor <[email protected]> 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: > [email protected] >with the single line: > unsubscribe emc-pstc > >For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > >For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > >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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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.
