Re: USRP N210 Synchronization

On 03/10/2021 07:26 AM, Martin Braun wrote:
> USRPs typically operate with a 25% duty cycle PPS (i.e., 250 ms on,
> 750 ms off). But they will work with pretty much any duty cycle.
>
> Check the levels are within limits (I don't have them off the top of
> my head). I would suggest you connect your PPS/10 MHz generator
> directly to the USRP, and see if that works. Then, the splitter to see
> if that's ruining your levels.
>
> Note that we sell such a splitter:
> https://www.ettus.com/all-products/octoclock/
> I might be more than your budget, which I understand, but it's what we
> usually use for these types of applications.
>
> --M
>
The input voltage for 1PPS on N2xx is between 3.3V and 5V -- so
basically LVTTL input levels. My recollection is that going below 3.3V
leads to unreliable 1PPS, from threads on this topic back in 2018.

Cheers
Marcus