[time-nuts] Re: Commercial solution - 122.88 MHz low noise source

[ghf at hoffmann-hochfrequenz.de]

Am 2022-04-05 3:34, schrieb ed breya:
> I was curious and looked up this Red Pitaya SDR thing (which I had
> never heard of - I would have guessed a poisonous snake, without the
> internet), and the Abracom TCXO. It's getting a little confusing to
> keep up with what's going on.
> 
> First, does the installed TCXO have EFC capability, or not? Jeff
> apparently says not, while Gerhard says yes. According to the
> datasheet, the ABLNO can be an XO only (no suffix), or a VCXO ("V"
> suffix). Jeff should be able to tell which, by inspection.

The Abracon can, if you choose the right option.
There is no Abracon at least on my older RedPitaya. There is just a
4*6 mm or so thingy on the board, on the microscope I can read 
"ExpressO"
but I really don't care. My solution is the ECS xtal oven board,
picture from my previous post. Attached is the phase noise of the 
ECOC2522,
I got it from ECS.
The RP can be strapped for external sample clock and my board has a
LVDS driver to feed it. When I lock my synthesized transverters to a
precision reference, then it makes no sense to have the SDR floating
around.

The circuit of the RP is on their web site, only sligthly censored.

Also interesting: The Koheron project, where they somehow synced 4 RP
over their SATA connectors.
<  
https://github.com/Koheron/koheron-sdk/tree/master/examples/red-pitaya/cluster 
   >
<  https://www.koheron.com/blog/2016/11/29/red-pitaya-cluster     >

<  
https://www.koheron.com/blog/2018/07/08/phase-noise-measurement-alpha250 
       >
It seems that an external clock can do good.

regards, Gerhard
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