One other possibility occurs to me that might be doable with surplus gear and sticks to the budget. Instead of using WR, give up on getting time of day and just send a 1 kHz pulse stream in each direction. Each station then measures against its own GPSDO clock using a standard/homebrew TIC and records the difference. This is ambiguous modulo 1 ms but this is trivially resolved using GPS. You also probably know the distance between the stations to much better than 1 ms = 300 km :-) . You then post-process but this can be done with very little latency if you're keen.
Cheers Michael On Mon, May 2, 2016 at 1:44 AM, Tom Van Baak <t...@leapsecond.com> wrote: >> Has anybody experienced with free-space optical gigabit Ethernet >> links? I am curious about whether the transceivers have a fixed >> latency or at least a latency one can easily quantify online. This is >> the trickiest part for adding WR support on top of a given physical >> layer. > > Hi Javier, > > When searching this topic I ran across a commercial laser solution: > > http://www.laseroptronics.com/products.cfm/product/27-0-0.htm > http://www.laseroptronics.com/index.cfm/id/57-66.htm > http://www.laseroptronics.com/index.cfm/id/57-69.htm > etc. > > But, according to /57-67.htm it "starts" at $15k per node. Plus there's the > cost of all the WR pieces, assuming the two are even compatible. So this is > vastly above the ~$2k budget mentioned by OP. I also assume OP is not ready > to embark on a one-off, multi-man-year R&D project. > > This particular issue -- how to synchronize (or, at least phase compare) > multiple oscillators by a two-way laser link over a few km to within 500 ps > -- is really quite interesting. It would, for example, allow me to do live > monitoring of 5071A Cs time dilation on my next mountain-valley relativity > experiment. > > /tvb > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.