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Agilent E7495 linux root account

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technogeeky:
Can you guys post screenshots of the noise floor of your instruments? I am wondering noise floor curve on my instrument is wrong or not. See the attached images. This is with nothing connected at all.

The screenshots show the measurements and diffs between:

* 500 kHz and 375 MHz (+2.8dB)
* 375 MHz and 2.7 GHz (+10.4dB)
Something tells me that a gain of 10.4dB over that range is probably not a good thing.

TheSteve:
Looks pretty normal to me.

Edit:

I've attached a full span screen shot of my N1996A - however it is only valid to 3 GHz. The drop you see is when it passes 2.7 GHz. The noise floor from 3 GHz to 6 GHz should actually rise as the frequency increases. It doesn't as that portion of it is uncalibrated(I enabled the 3-6 GHz portion myself).

technogeeky:

--- Quote from: PA0PBZ on March 07, 2017, 10:01:22 am ---
--- Quote from: kirill_ka on March 07, 2017, 09:30:52 am ---
--- Quote from: technogeeky on March 06, 2017, 08:21:07 am ---
Also, I played around with the files in /flash/egServer/Dragonfly/Recievers, like E7495A and CPXSRC. You can indeed change things here and sometimes see the effects (e.g. you can change E7495A to have Freq Range be 3000e6, and it makes it possible to enter that value). However, some of these changes will have no effect for other reasons (here, I assume it's because there is actually a filter which sharply cuts off at ~ 2.7GHz).


--- End quote ---
Limitations are spread in configs, gui, elgato, dsp code and hardware. I mean along with configs there are many hardcoded values.

--- End quote ---

If the 7495 is anything like the N1996 (and we have a lot of reasons to believe so) you will not be able to go above 2.7GHz.
The N1996 has 2 receive paths, one for 0.1MHz - 2.7GHz and the other for 2.7GHz to 3/6GHZ. Since the N1996, depending on the model, has an upper limit of 3 or 6GHz both receive paths are there, and that is why you can change the 3GHz model to 6GHz by changing the upper limit value. Since the 7495 goes to 2.7GHz only I assume that the upper part is missing in the 7495. See below the N1996 receive path:



--- End quote ---

Do you have more information from this source? I'd like to see any schematics or block diagrams I can find.

PA0PBZ:

--- Quote from: technogeeky on March 15, 2017, 12:40:22 pm ---Do you have more information from this source? I'd like to see any schematics or block diagrams I can find.

--- End quote ---


N1996 Service manual guide: https://www.dropbox.com/s/5axcrduzvvd3rvb/N1996-90006.pdf?dl=0

ferdinandkeil:

--- Quote from: technogeeky on March 08, 2017, 10:46:33 pm ---Can you guys post screenshots of the noise floor of your instruments? I am wondering noise floor curve on my instrument is wrong or not. See the attached images. This is with nothing connected at all.

The screenshots show the measurements and diffs between:

* 500 kHz and 375 MHz (+2.8dB)
* 375 MHz and 2.7 GHz (+10.4dB)
Something tells me that a gain of 10.4dB over that range is probably not a good thing.

--- End quote ---

Did the same test with my E7495B and got similar results. Looks to be normal.

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