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My understanding of SA's is that their displays are not fast.
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There is no advantage is sweeping too fast and a lot of disadvantages. I can't imaging needing more than 100KHz of bandwidth on the X and Y axes. That should give you plenty of time to draw the spectrum graph and the little bit of text. As long as you are faster than the human bandwidth there is no need to go faster. Pete. ----- Original Message -----
From: Kuba Ober To: hp_agilent_equipment@... Sent: Thursday, September 01, 2011 8:23 PM Subject: Re: [hp_agilent_equipment] X-Y to VGA/USB converter > What is the speed of the old Tek and HP X/Y monitors? The question is: are those fast enough to be used to replace what was inside the box of various otherwise useful HP instruments. I'm also more than willing to have potentially extra functionality included, perhaps bypassing some of the circuitry in the instrument. My favorite would be to have a swept FFT by taking in directly the baseband output from a SA -- with a 16 bit ADC it should be feasible. I'm also looking at digitizing the frequency of the LO outputs from a SA to obtain precise frequency for any part of the display. I think I previously incorrectly said digitizing IF -- that's of course possible, but it'd be the last IF if anything. Inputting any number of LOs and digitizing their frequency should be very simple, as would be calculating the resulting center frequency. I think the hardest part would be to make sure my device won't pollute the LOs, so I'd be learning some new tricks too. My starting point is to run my 7L14 with a mainframe with no CRT, then to tap LO1 and LO2 outputs for precise center frequency, then to tap directly into the last IF output before the video processor (detector, LOG/LIN, digitizer). I can't really afford to get various other instruments that this would work with, so I thought it'll be easier to ask for ideas instead of having to rummage through downloads of HP manuals. So my appeal is as follows, to make it easy and technical: if you have a SA or another instrument that you'd like to get a replacement display for, give me the specs on its X-Y-Z outputs, and also on the LO frequency ranges and levels -- obviously if those LOs are available as outputs without disassembly. That's give me some idea as to how to set up the signal processing (gains, bandwidths, etc). Kuba |
