[time-nuts] 1 pps Accuracy in two locations

Wed Dec 4 21:21:07 UTC 2019

I totally messed up what I wanted to say.  Here's the corrected version.

In 1 ps, signal travels 0.3mm.  Everything has to be on one die (as in die in a chip) as propagation delay in cabling alone will add enough errors.

(I'm sorry tvb.... for creating more job for you to do)
--------------------------------------- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

    On Wednesday, December 4, 2019, 3:07:34 PM EST, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:  

 Also, at that speed, signal travels 0.3mm per second, assuming zero velocity factor.....  Everything will have to be on chip scale to realize that.

--------------------------------------- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG

    On Wednesday, December 4, 2019, 11:01:12 AM EST, Tom Van Baak <tvb at leapsecond.com> wrote:  

 Martyn,

 > I'm always being asked to provide equipment that can produce two 1
 > pps outputs aligned to each other to within a few ps.

They should look at their best 1PPS on a 'scope. You can get ns with 
care; I doubt ps is possible. I mean, that's THz BW isn't it?

Can you share with us what their application is?

 > So they are asking for two of my GNSS frequency standards with 1 pps
 > outputs.
 >
 > The 1 pps outputs being derived from the rubidium oscillator (which
 > is aligned to GPS/GNSS)
 >
 > The best I think I can achieve is in the low ns range.

Right. It will be ns, not ps. Forget about using GNSS for ps level timing.

 > Does anyone know how this can be achieved?

Google for papers by high-end national timing laboratories. Words like: 
active temperature stabilized (phase stabilized) bidirectional optical 
fiber links.

Very possible, very expensive, quite common now. I'd guess most of the 
timing centers in Europe are linked this way.

/tvb

On 12/4/2019 1:40 AM, martyn at ptsyst.com wrote:
> Hello,
>
>  
>
> I'm always being asked to provide equipment that can produce two 1 pps
> outputs aligned to each other to within a few ps.
>
>  
>
> These two 1 pps pulses are not in the same location and could be 100 metres
> to a few km away.
>
>  
>
> So they are asking for two of my GNSS frequency standards with 1 pps
> outputs.
>
>  
>
> The 1 pps outputs being derived from the rubidium oscillator (which is
> aligned to GPS/GNSS)
>
>  
>
> The best I think I can achieve is in the low ns range.
>
>  
>
> Does anyone know how this can be achieved?
>
>  
>
> Regards
>
>  
>
> Martyn
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

_______________________________________________
time-nuts mailing list -- time-nuts at lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.