Re: [time-nuts] quartz drift rates, linear or log

2016-11-13 Thread Bob Camp
Hi > On Nov 13, 2016, at 9:34 AM, Artek Manuals wrote: > > Tom et all > > While our instinct based on some "pre- knowledge" of the aging and drift > processes is to try and fit these to linear or logarithmic curves there is a > third possibility . That is, in fact the aging is not exactly e

Re: [time-nuts] quartz drift rates, linear or log

2016-11-13 Thread Tom Van Baak
>> http://leapsecond.com/pages/tbolt/TBolt-10day-fit1-e10.gif > Hi Tom, > > Fascinating when you've done that linear fit - many of the plots now look > very similar, > suggesting environmental conditions? From that it would now be nice to log > temperature, > pressure, humidity, (& mains voltag

Re: [time-nuts] quartz drift rates, linear or log

2016-11-13 Thread Peter Vince
Hi Tom, Fascinating when you've done that linear fit - many of the plots now look very similar, suggesting environmental conditions? From that it would now be nice to log temperature, pressure, humidity, (& mains voltage?), and see if there is any correlation there. Wonderful to see pl

Re: [time-nuts] quartz drift rates, linear or log

2016-11-13 Thread Artek Manuals
Tom et all While our instinct based on some "pre- knowledge" of the aging and drift processes is to try and fit these to linear or logarithmic curves there is a third possibility . That is, in fact the aging is not exactly either and may be better represented in fact be some kind of polynomial

Re: [time-nuts] quartz drift rates, linear or log

2016-11-13 Thread Tom Van Baak
Thanks for all the comments on this thread. Here is the first set of replies: Don Latham: > Interesting, Tom. I don't think I see any of those pesky grain boundary > shifts or readjustments in the lattice structure? If I remember, these > can cause instant shifts in frequency that do not h

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Bob Camp
Hi Exact info on mass transfer is a bit complicated. A 5 MHz 5th overtone is a bit thicker and more massive than a 100 MHz 5th. Both are thicker (and more massive) than a 100 MHz fundamental. On top of that the blank is not equally sensitive to mass at all points on it’s surface. Finally, gold

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Scott Stobbe
Those are wonderful plots :) I vaguely recall that a 1ppm frequency shift is approximately equivalent to the mass transfer of one molecular layer of a crystal. So at some point your counting atoms if there was no noise, thermal disturbance, mechanical disturbance... On Sat, Nov 12, 2016 at 5:00 P

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Charles Steinmetz
Attila wrote: Yes, depending on the data you show, it is not clear whether one should do a linear or a logarithmic fit. When the purpose is correcting a GPSDO local oscillator during holdover, it depends on how long one expects to trust the corrected frequency. Practical realities make it po

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread jimlux
On 11/12/16 1:54 PM, Tom Van Baak wrote: There were postings recently about OCXO ageing, or drift rates. I've been testing a batch of TBolts for a couple of months and it provides an interesting set of data from which to make visual answers to recent questions. Here are three plots. The plots

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Tom Miller
Just out of curiosity, what is the age of each of these Tbolts? (i.e. date codes?) Thanks - Original Message - From: "Tom Van Baak" To: "Discussion of precise time and frequency measurement" Sent: Saturday, November 12, 2016 4:54 PM Subject: [time-nuts

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Bob Stewart
: Saturday, November 12, 2016 3:54 PM Subject: [time-nuts] quartz drift rates, linear or log There were postings recently about OCXO ageing, or drift rates. I've been testing a batch of TBolts for a couple of months and it provides an interesting set of data from which to make visual answers to r

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Bob Camp
Hi One would *guess* that the OCXO’s all left the factory set to center at zero volts on the EFC. One thing that is pretty easy to do is to look at the date code on the OCXO and the EFC voltage. That plus the sensitivity (one could cheat and look at the frequency rather than EFC) will give you

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Attila Kinali
On Sat, 12 Nov 2016 13:54:14 -0800 "Tom Van Baak" wrote: > 2) attached plot: TBolt-10day-fit0-e10.gif ( > http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif ) > > Here we zoom in by changing the Y-scale to 1e-10 per division. The X-scale > is still 10 days. Now we can see the drift muc

Re: [time-nuts] quartz drift rates, linear or log

2016-11-12 Thread djl
Interesting, Tom. I don't think I see any of those pesky grain boundary shifts or readjustments in the lattice structure? If I remember, these can cause instant shifts in frequency that do not heal? Don On 2016-11-12 14:54, Tom Van Baak wrote: There were postings recently about OCXO ageing, o

[time-nuts] quartz drift rates, linear or log

2016-11-12 Thread Tom Van Baak
There were postings recently about OCXO ageing, or drift rates. I've been testing a batch of TBolts for a couple of months and it provides an interesting set of data from which to make visual answers to recent questions. Here are three plots. 1) attached plot: TBolt-10day-fit0-e09.gif ( http: