phase noise measurements

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DeltaPapaCA
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phase noise measurements

Post by DeltaPapaCA » Mon Jul 15, 2019 3:34 pm

I am looking at the purchase of the PicoScope 4262 to use for baseband analysis for phase noise measurements. There has been a fair amount of discussion in the forums regarding both phase noise measurements, dBc/Hz, calibration, normalization, etc. None appears to be very recent. Has anyone made progress on dedicated apps specifically for phase noise measurements? What about making multi decade measurements where the FFT size is fixed for each decade, or two decades? This would cause the resolution BW to change along with the offset frequency, at least in steps. Of course, the data would need normalization to 1 Hz BW. This should allow much faster measurements. What about other commercially available software that can utilize the PicoScope hardware?

A hardware question. I like the higher 80 MSPS sample rate offered by the 4224 'scope and 16 bit resolution and lower noise floor of the 4262 'scope. Are there any near term plans for a 14 bit or 16 bit unit with higher than 10 MSPS sample rates? Even 25 MSPS or 30 MSPS would be a very useful upgrade. Maybe with larger buffer sizes too? It never hurts to ask, right?

Gerry
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Re: phase noise measurements

Post by Gerry » Tue Jul 16, 2019 10:31 am

Hi DeltaPapaCA,

There are more recent discussions related to phase noise measurements, or at least phase noise measurements with the application of our Software Development Kit (see here: https://www.picotech.com/library/oscilloscopes/picoscope-software-development-kit-sdk) to creating the required measurement tool, e.g. this discussion: https://www.picotech.com/support/topic39794.html?&p=142266#p142266, and others posted by Dan (who has also made more comprehensive posts on other forums).

Regarding your suggestion, unfortunately we don't have that functionality in the current software version. The only other available software that I am aware of that performs something similar to what you ask is the Bode plot software "FRAScope" (here: https://bitbucket.org/hexamer/fra4picoscope/wiki/Home) that plots the frequency and phase repsonse for analysis. However, what you can do for your exact requirements is export the Time Domain data, peform your own FFT with the appropriate setup of the data (including using bin widths proportional to frequency, or log of the frequency relative to 1Hz) using one of the many FFT libararies out there, and then plot the data as you would like it to be displayed.

Unfortunately, we are not able to share information of up and coming new products ahead of our marketing team.

Regards,

Gerry
Gerry
Technical Specialist

DeltaPapaCA
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Re: phase noise measurements

Post by DeltaPapaCA » Tue Jul 16, 2019 2:25 pm

Hi Gerry,

Thank you for your prompt reply to my questions. I made an error in my comments as you posted a detailed discussion on June 12 that I neglected to credit. I fully expect that the tools to support phase noise measurements will continue to be developed and evolve. I suspect that the best way for me to proceed is get the 4262 unit and get some 'hands on' time on the unit. Even without the more specialized BW changes, the log F x-axis, ENB function, averaging, and reference functions may very well support my near term needs. I will do further research and study at the referenced links. Thank you.

Doug

Gerry
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Re: phase noise measurements

Post by Gerry » Wed Jul 17, 2019 4:18 pm

No problem.

Let us know if you find that that is not the case. We certainly don't have all the bases covered in our products, so we welcome your points of view, and there are always interesting twists on measurement applications that give us an opportunity to adapt what we have, or encourage other users that have accomplished similar goals to share what they know, after all, that's what these forums are for!

Regards,

Gerry
Gerry
Technical Specialist

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