Hi Your Rb should be good to about 10 ppt at 1 second. Thats 10 ps. Your OCXO might be good to 1 to 10 ppt at 1 second that’s 1 to 10 ps. Your 5334 has a measurement resolution of 2 ns single shot (which is what matters in this case), that’s 2000 ps. You would like to have a resolution 5X better than the thing you are trying to measure.
Your counter gate time error in ppt scales directly as tau. It’s always 2 ns, but at 10s tau it’s going to be 200 ppt not 2,000 ppt. Your Rb ADEV likely scales as square root of tau. At 100 seconds it’s 1 ppt, which would be 100 ps. You still aren’t there yet. Who knows what the OCXO is doing, let’s say it’s <= 10 ppt. Still not there. At 10,000 seconds the Rb might get to 0.1 ppt. That would be 1,000 ps. Your counter still isn’t there. Who knows what the OCXO is doing at 10,000 seconds. The counter might follow the OCXO. ——————— Simple answer - doing this directly with a counter is not the best approach. Bob On Feb 6, 2014, at 5:23 PM, Bob Stewart <[email protected]> wrote: > I'm getting a little more familiar with ADEV and OADEV now. With a little > help from Tom, I've put together gnuplot scripts and his software to get a > decent plot. But, as some time-nuts have pointed out, my measurements are of > one part of my system being compared to another. Would I learn anything > useful by hooking my Rb standard up to my 5335A and comparing that to the > OCXO? How long should I let the Rb heat up before starting the test? I'm a > bit uncertain about the result of comparing a stable clock of questionable > accuracy to an accurate clock of questionable stability. Hopefully I said > that right. > > thanks, > > Bob - AE6RV > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
