Said, how complex is your 20pS time interval counter? Is it analog, FPGA, something else (if you can disclose some info, of course)?
On Sat, Mar 31, 2012 at 11:44 PM, Hal Murray <hmur...@megapathdsl.net>wrote: > > mar...@ptsyst.com said: > > I’ve seen that the peak to peak jitter is reduced from something like 27 > ns > > to < 10 ns. > > > Is this a reduction of just the jitter, or is the actual accuracy to UTC > > also improved by this amount. > > Have you read the hanging-bridges paper? > Tom Clark and Rick Hambly: Timing for VLBI > http://gpstime.com/files/tow-time2009.pdf > I think that is the key to understanding this area. > > If you could average over many sawtooth cycles, you should get an accurate > answer. > > The problem is that you don't get to pick how many cycles fit into your > averaging time. The sawtooth pattern is the beat between two frequencies. > One of them is drifting with time/temperature. If you are unlucky, the > beat > frequency can be very very low. > > The sawtooth correction lets you correct on a cycle-by-cycle basis. You > don't need to average over many samples. > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > > _______________________________________________ > 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.
