Hi The assumption is that other than OCXO short term and aging - all the bumps and dips in the road have been eliminated. As I mentioned earlier that is indeed an assumption that has a lot of sub assumptions that go into it.
It also assumes that GPS is correct over the time period involved. To put some numbers on all this, here's some guesses. Accuracies of GPS on the TBolt are an "eyeball" 2 ns or so. A thousand seconds is pretty long for an OCXO short term floor. That would give you 2x10^-9 / 1000 = 2x10^-12 as a limit on what's being done. At 10,000 seconds the OCXO would have to be 2x10^-13 - that's not happening. At 100 seconds it would need to be 2x10^-11 which is pretty high probability. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Tom Van Baak Sent: Thursday, January 27, 2011 4:37 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Temperature stability for Thunderbolt: results >>By this (quite possibly imperfect) measure: When the EFC goes down >>3:1, you have improved the thermals by 3X. If you started at 1 C >>swings, the OCXO is now seeing 1/3 C swings. > > Agreed (re: the EFC component that correlates to changes in Tbolt > ambient temperature). A number of posts have mentioned LH measurements and variations in DAC voltage or TI or OSC values. I'm curious how close to the truth this is. An analogy: suppose my goal is to drive 55 mph for a day as smoothly as possible. There are two judges. One judge is a passenger who at all times is looking at my foot. Over the hours they see me push the accelerator at varying depths; sometimes slacking off quite a bit and other times pushing fairly hard. Occasionally they even see me tap the brake. They collect all this raw data and make graphs and conclude that I am a mediocre driver since there was a lot of variation in my performance and I could have done much better. The other judge is a fully instrumented time nut in a vehicle behind me; watching the position, velocity, and acceleration of my car at all times to many decimal places. Moreover they collect environmental and road condition data. They see me keep really close to 55 mph regardless of the straight roads, or all those up and down hills; around gradual and tight curves, in daylight and at night, during the warmer day and cooler night. They imagine I must be highly motivated and alert, constantly and tirelessly adjusting acceleration to meet the demands of the uneven road and driving conditions. They conclude I'm an excellent driver. Which judge is more correct? Which judge is LH? If someone already has raw TBolt data (both internal and external, simultaneously) with and without fine temperature regulation let me know; we can see how well the judges compare. /tvb _______________________________________________ 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.
