[time-nuts] Noise Floor

[Attila Kinali]

On Tue, 24 Mar 2020 18:26:28 +0200
Anders Wallin <anders.e.e.wallin at gmail.com> wrote:

> It would be interesting to know what ADC was used and if there's an
> SDR-board out there that uses the same ADC.
> Our experience with the Ettus radios is that although they have 2 channels
> there is a lot of cross-talk between rx1 and rx2 channels, which makes a
> diy SDR-based phase-meter challenging.

BTW: I forgot to mention:

If you want an SDR like system to play with, try the ADC/FPGA board
that Nicholas designed as part of his master thesis at CERN (in
the group that brought us white rabbit) [1]. Design files are all
online, including his thesis itself that should contain all the
design decisions (if not just ask). To the best of my knowledge
the design should be as low noise as the ADC can get to. You will
not get the isolation the Timepod or PhaseStation has, due to using
a 4-channel ADC, but it should be good for quite a few things.
Cost for the small run (5 boards) they did was IIRC 600CHF per board.
I don't remember whether that included the MicroZedBoard or not.

			Attila Kinali


[1] https://www.ohwr.org/project/r19-tdc-del-a/wikis/home

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