[time-nuts] Re: gpsdo by leo bodnar & picdiv

[Marek Dorsic]

Hello,

     I replicated your scenario with LeoBodnar and PicoDIV and it worked without problems. 
Note, that the PicoDIV starts to output PPS on GPIO17 only after SYNC signal is received. If no sync required, just short the GPIO19 and GPIO20 pins, or use the signal on GPIO21.

Kind regards,
   .md

> On 25 Nov 2024, at 15:47, Brian Lloyd via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz.
> 
> If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps.
> 
> Best regards.
> 
> On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote:
> 
>> Hi,
>> 
>> A while ago I bought the following GPSDO:
>> https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
>> I wanted to let it produce a 1 Hz pulse but if I feed its output to a
>> PICDIV or a PICODIV, then nothing comes out. I verified with a scope
>> that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
>> GPSDO by Leo (the
>> https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234
>> - it got lost during relocation :-/) and with that one, it all worked
>> just fine.
>> What also works fine is the current GPSDO -> reference clock input of
>> a DG1022Z and then use that function generator as a divider. Not
>> ideal though (the rigol has loud fans, a picdiv doesn't).
>> Any ideas what it could be?
>> 
>> regards
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> 
> --
> 
> Brian Lloyd
> WB5BL - J79BL - NNA6BL
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> Spring Branch, TX 78070
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