If every station has its own GPSDO, what is the purpose of the optical transfer?
On Mon, May 2, 2016 at 11:14 AM, Michael Wouters <michaeljwout...@gmail.com> wrote: > 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. _______________________________________________ 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.