[time-nuts] Yet another GPSDO project.

[Jim Harman]

Also Nick Sayers's GPSDO described here
https://www.tindie.com/products/nsayer/gps-disciplined-ocxo/
is based on the same design and he has performance data.

On Tue, Mar 19, 2019 at 8:32 PM Jim Harman <j99harman at gmail.com> wrote:

> Tobias asked,
> @Jim Harman
> Indeed I know Lars' GPSDO. Can you tell what performance you achieved with
> one of those?
>
> It is hard for me to quantify the performance because I don't have
> anything better to compare it to. The TIC resolution is 1 nsec.
>
> I can say that it will stay phase locked to the 1 pps from my GPS for
> months at a time and if I set the time constant to 1,000 sec, the 300 sec
> average error detected by its TIC is within +/- 5 nsec more than 50% of the
> time. The maximum error is about 100 nsec.
>
> If I compare the variations in the TIC error from one day to the next, I
> can easily see variations of about +/- 20 nsec on a period of just less
> than 24 hours caused by the shifting geometry of the satellites overhead. I
> am sure this could be improved significantly if I used a a timing-type GPS
> instead of the Adafruit one I have.
>
> Lars may have better data in his write-up,
>
>> --
>>
>
> --Jim Harman
>
>

-- 

--Jim Harman