[time-nuts] distribution of precision time via fiber networks

Bob Martin aphid1 at comcast.net
Sat Sep 1 13:06:04 EDT 2018


Jim,

   You can still find the Deep Space Network fiber-optic 
distribution equipment for sale on the Microsemi website:

https://www.microsemi.com/product-directory/modular-synchronization-systems/4168-time-code-translator

   I designed the hardware for NASA's DSN upgrade while at Timing 
Solutions Corp. I remember having to design and lay out 23 circuit 
boards within about 5 months when we got that contract. The Time 
Code Translator was the hardest to get right because it did so much.

  I never paid much attention to where it went because it was "on to 
the next project" as soon as it was completed. Still it's nice to 
see that it got deployed and (hopefully) worked.

Bob Martin


On 9/1/2018 8:25 AM, jimlux wrote:
> On 9/1/18 7:00 AM, Scott McGrath wrote:
>> There was a paper published when NASA did something similar for 
>> LC39 and the VAB.    Anyone have a copy because the link i have is 
>> dead.
>>
>> As I recall it was some trick and compensating for thermal effects 
>> on the fiber itself was a large part of the effort.
>>
>>
> 
> I don't know about at the Cape (I'm not sure what the *need* for 
> precision timing at that level might be, but it could be there).
> 
> There's a whole lot of stuff that's been published about 
> distributing frequency references and holding tight phase tolerances 
> at the Deep Space Network stations, since they do arraying using 
> multiple apertures, as well as run of the mill VLBI stuff.
> 
> https://deepspace.jpl.nasa.gov/dsndocs/810-005/304/304B.pdf is the 
> "production" system for DSN, but as mentioned therein, there are 
> various improved schemes in development.
> 
> You might search for publications by Bob Tjoelker.
> 
> 
>   While there are JPL papers in IEEE sources behind paywalls, almost 
> always, they're also available in NTRS (https://ntrs.nasa.gov/) or 
> JPL's piece (https://trs.jpl.nasa.gov/). If the paper isn't online 
> for free in that location, you can send an email to NASA (there's a 
> form at ntrs.nasa.gov) or the JPL librarian (link at the trs site) 
> and they'll send it to you.  Another good place to look for DSN 
> related stuff is here:
> 
> https://ipnpr.jpl.nasa.gov/
> 
> The Chinese seem to have been publishing lots of papers on Arxiv 
> recently about "joint time and frequency distribution"
> 
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