Re: [time-nuts] Thermal impact on OCXO

Thanks Azelio, I have also thought that the EFC range probably says something. The datasheet for the OFC4834 says EFC range +-0.4ppm and that that should be enough for 15 years. The OFC MC834, I have seems very similar, but without EFC. So my 68ppm drift is well within the +-400ppb Lars

Re: [time-nuts] Thermal impact on OCXO

Hi Bob, I was afraid that the answer should be like this (smile). One paper from MTI that probably confirms that aging prediction is difficult: http://www.mti-milliren.com/MTIPapers/Ext_Aging_Perf_Results.pdf Lars From: Bob Camp Sent: den 19 november 2016 00:23 Hi > On

Re: [time-nuts] Thermal impact on OCXO

Are Oscilloquartz's Star-4 commands described somewhere? I can't find them in the wild... On Sat, Nov 19, 2016 at 4:34 AM, Mark Sims wrote: > Several years ago I replaced the OCXOs in some Tektronix DC5010 counters with > surplus Oscilloquartz 8663 DOCXOs. The darn things

Re: [time-nuts] Thermal impact on OCXO

One starting point to figure out the 10 years aging can be the datasheet of an OCXO: MTI240: per year, 3.0E-7, in 10 years must be less than 30.0E-7 MTI220: per year, 1.0E-6, in 10 years < 10.0E-6 Bliley NV26R: 17 years, 5.0E-6 OSA8663: per year, 3.0E-8, in 10 years < 30.0E-8 On Fri, Nov 18, 2016

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 18, 2016, at 1:31 PM, Lars Walenius wrote: > > Hi Bob (and all others), > > I agree to all your points but am curious to your comment: ”that OCXO is > aging a lot for one that has been on that long”. > As I have only done this test and seen no other

Re: [time-nuts] Thermal impact on OCXO

Hi Bob (and all others), I agree to all your points but am curious to your comment: ”that OCXO is aging a lot for one that has been on that long”. As I have only done this test and seen no other test of OCXO´s powered over at least ten years, I have no idea what is reasonable. I also guess I

Re: [time-nuts] Thermal impact on OCXO

A similar practice at a small East coast microwave company back in the 60s. Except the product was magnetrons that were used in the Talos missile system (if memory serves). On Nov 18, 2016, at 01:30, David wrote: I have only heard of and never observed the problem of

Re: [time-nuts] Thermal impact on OCXO

I have only heard of and never observed the problem of manufacturers cutting the middle out of a gaussian distribution for tighter tolerance parts. Robert Pease of National Semiconductor had an even better story: I recollect the story of one of the pioneering transistor companies, back in the

Re: [time-nuts] Thermal impact on OCXO

> AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > From: Bob Camp <kb...@n1k.org> > To: Discussion of precise time and frequency measurement <time-nuts@febo.com> > Sent: Thursday, November 17, 2016 11:39 AM > Subject: Re: [ti

Re: [time-nuts] Thermal impact on OCXO

39 AM Subject: Re: [time-nuts] Thermal impact on OCXO Hi Most (> 99%) OCXO’s are made to custom specs for large OEM’s. The sort consists of “ship these” and “send these to the crusher”.  Needless to say, the emphasis is on a process that throws out as few as possible. Bob > > On

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 17, 2016, at 10:34 AM, Scott Stobbe wrote: > > I couldn't agree more, that, once you add a correlated disturbance or > 1/f^a power law noise, things get even messier. Gaussian is just the > easiest to toss in. > > I once herd a story from once upon a time

Re: [time-nuts] Thermal impact on OCXO

On Thu, 17 Nov 2016 10:34:06 -0500 Scott Stobbe wrote: > I couldn't agree more, that, once you add a correlated disturbance or > 1/f^a power law noise, things get even messier. Gaussian is just the > easiest to toss in. Side note: 1/f^a noise is (usually) Gaussian.

Re: [time-nuts] Thermal impact on OCXO

I couldn't agree more, that, once you add a correlated disturbance or 1/f^a power law noise, things get even messier. Gaussian is just the easiest to toss in. I once herd a story from once upon a time that, if you bought a 10% resistor, what you ended up with is something like this in the figure

Re: [time-nuts] Thermal impact on OCXO

It sounds like you knew what I meant by linearization, but I really should have wrote linearize in parameters. Of course functions like F = Ax^2 + Bx + C F = Asin(omega t) + Bcos(omega t) fit extremely well with ordinary least squares. Well there is no free lunch, nlsq has its own challenges,

Re: [time-nuts] Thermal impact on OCXO

On Tue, 15 Nov 2016 23:58:31 -0500 Scott Stobbe wrote: > Do you recall if you fitted with true ordinary least squares, or fit with a > recursive/iterative approach in a least squares sense. If the aging curve > is linearizable, it isn't jumping out at me. Least square

Re: [time-nuts] Thermal impact on OCXO

Hi The issue in fitting over short time periods is that the noise is very much *not* gaussian. You have effects from things like temperature and warmup that *do* have trends to them. They will lead you off into all sorts of dark holes fit wise. Bob > On Nov 16, 2016, at 6:48 PM, Scott Stobbe

Re: [time-nuts] Thermal impact on OCXO

Hi Your data demonstrates a couple of things: 1) There are a number of different things going on with that OCXO and some things are a lot less predictable than others. 2) Oscillators do drop rate while on power. 3) Oscillators that age a lot are easier to model (yes, that OCXO is aging a lot

Re: [time-nuts] Thermal impact on OCXO

A few different plots. I didn't have an intuitive feel for what the B coefficient in log term looks like on a plot, so that is the first plot. The same aging curve is plotted three times, with the exception of the B coefficient being scaled by 1/10, 1, 10 respectively. In hand waving terms, it

Re: [time-nuts] Thermal impact on OCXO

Lars, I've broadly understood the aging in the first days to month as being dominated by "bake-out". It's well fit with a logarithmic curve but the effect is so large in the first weeks that it hides the true long term aging (which could well have a different direction). Tim N3QE On Wed, Nov

Re: [time-nuts] Thermal impact on OCXO

Many thanks to Dan! A question: About what temperature span has it been during these runs? Or do you have the temperature coefficient? Seems that the yellow line has about 50ppt due to temperature. For the orange it seems to me to have about 6E-12/day aging, is that high? Compared to the

Re: [time-nuts] Thermal impact on OCXO

FWIW. Between 2001 and 2011 I run a 5MHz OCXO (in a box). It is a 2x3inch type without EFC marked OFC MC834X4-009W with date code 97. Probably it was from some base station testing and it had been sitting in my shelf since 98. The OCXO were battery backed but at two occasions (2004 and 2007) we

Re: [time-nuts] Thermal impact on OCXO

Hi The original introduction of 55310 written by a couple of *very* good guys: http://tycho.usno.navy.mil/ptti/1987papers/Vol%2019_16.pdf A fairly current copy of 55310: https://nepp.nasa.gov/DocUploads/1F3275A6-9140-4C0C-864542DBF16EB1CC/MIL-PRF-55310.pdf The “right” equation is on page 47.

Re: [time-nuts] Thermal impact on OCXO

Hi Bob, Do you recall if you fitted with true ordinary least squares, or fit with a recursive/iterative approach in a least squares sense. If the aging curve is linearizable, it isn't jumping out at me. If the model was hypothetically: F = A ln( B*t ) F = A ln(t) + Aln(B) which could

Re: [time-nuts] Thermal impact on OCXO

Hi If you already *have* data over a year (or multiple years) the fit is fairly easy. If you try to do this with data from a few days or less, the whole fit process is a bit crazy. You also have *multiple* time constants involved on most OCXO’s. The result is that an earlier fit will have a

Re: [time-nuts] Thermal impact on OCXO

On Mon, Nov 7, 2016 at 10:34 AM, Scott Stobbe wrote: > Here is a sample data point taken from http://tycho.usno.navy.mil/ptt > i/1987papers/Vol%2019_16.pdf; the first that showed up on a google search. > > Year Aging [PPB] dF/dt [PPT/Day] > 1

Re: [time-nuts] Thermal impact on OCXO

kb...@n1k.org said: > Yes, that’s a bit of a long winded reply … sorry about that. It was also valuable. Thanks. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] Thermal impact on OCXO

c:* Bob Stewart <b...@evoria.net > <javascript:_e(%7B%7D,'cvml','b...@evoria.net');>>; Discussion of precise > time and frequency measurement <time-nuts@febo.com > <javascript:_e(%7B%7D,'cvml','time-nuts@febo.com');>> > *Sent:* Monday, November 7, 2016 9:34 AM

Re: [time-nuts] Thermal impact on OCXO

/GFS-GPSDOs/info From: Scott Stobbe <scott.j.sto...@gmail.com> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Monday, November 7, 2016 2:48 PM Subject: Re: [time-nuts] Thermal impact on OCXO Another n

Re: [time-nuts] Thermal impact on OCXO

Another nice plot! It looks like after 2am you see temperature swings of 1.5 degF roughly every 30 minutes? Correspondingly, the EFC line which is nominally ~2.8vdc sees swings of +-50 uV? On Monday, 7 November 2016, Bob Stewart wrote: > Hi guys, > First of all, thanks for the

Re: [time-nuts] Thermal impact on OCXO

rg> > To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency > measurement <time-nuts@febo.com> > Sent: Monday, November 7, 2016 1:01 PM > Subject: Re: [time-nuts] Thermal impact on OCXO > > Hi > > Thermocouples in test leads are nasty b

Re: [time-nuts] Thermal impact on OCXO

On Mon, 7 Nov 2016 17:47:19 + (UTC) Bob Stewart wrote: > When you say that OCXOs don't age in a linear fashion, what does that mean?  > IOW, is this a case where it's almost linear over a week, and the non- > linearity is only detectable when you consider the longer term? 

Re: [time-nuts] Thermal impact on OCXO

On Mon, 7 Nov 2016 17:20:58 + (UTC) Bob Stewart wrote: > There's something interesting on the far right hand side where the > temperature goes low and stays there.  The DVM value follows it down, but > then recovers while the temperature stays down.  I'm not sure what to

Re: [time-nuts] Thermal impact on OCXO

rg> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Monday, November 7, 2016 1:01 PM Subject: Re: [time-nuts] Thermal impact on OCXO Hi Thermocouples in test leads are nasty because they operate on the temperature delt

Re: [time-nuts] Thermal impact on OCXO

t; > Cc: Discussion of Precise Time and Frequency Measurement <time-nuts@febo.com> > Sent: Monday, November 7, 2016 11:54 AM > Subject: Re: [time-nuts] Thermal impact on OCXO > > Hi > > I would suggest you read the papers on the subject. They are out there. E

Re: [time-nuts] Thermal impact on OCXO

: Bob Camp <kb...@n1k.org> To: Bob Stewart <b...@evoria.net> Cc: Discussion of Precise Time and Frequency Measurement <time-nuts@febo.com> Sent: Monday, November 7, 2016 11:54 AM Subject: Re: [time-nuts] Thermal impact on OCXO Hi I would suggest you read the papers

Re: [time-nuts] Thermal impact on OCXO

eo/groups/GFS-GPSDOs/info > > > From: Bob Camp <kb...@n1k.org> > To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency > measurement <time-nuts@febo.com> > Cc: Scott Stobbe <scott.j.sto...@gmail.com> > Sent: Monday, November 7, 2016

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 7, 2016, at 12:45 PM, Chris Caudle wrote: > > On Mon, November 7, 2016 11:41 am, Chris Caudle wrote: >> On Mon, November 7, 2016 11:20 am, Bob Stewart wrote: >>> Either then OCXO is making up for the temperature change >>> by increasing the temperature >> >>

Re: [time-nuts] Thermal impact on OCXO

Hi Ok, You have a thermocouple junction at the + post on the DVM. You have one at the - post on the DVM. You have a junction at the + connection to the board. You have a junction at the - connection to the board. There are indeed more than that, but those four are pretty much a sure thing.

Re: [time-nuts] Thermal impact on OCXO

On Mon, November 7, 2016 11:41 am, Chris Caudle wrote: > On Mon, November 7, 2016 11:20 am, Bob Stewart wrote: >> Either then OCXO is making up for the temperature change >> by increasing the temperature > > Isn't that the entire point of an OCXO? Actually, that is not very precise language on my

Re: [time-nuts] Thermal impact on OCXO

On Mon, November 7, 2016 11:20 am, Bob Stewart wrote: > Either then OCXO is making up for the temperature change > by increasing the temperature Isn't that the entire point of an OCXO? -- Chris Caudle ___ time-nuts mailing list --

Re: [time-nuts] Thermal impact on OCXO

/groups/GFS-GPSDOs/info From: Scott Stobbe <scott.j.sto...@gmail.com> To: Bob Camp <kb...@n1k.org> Cc: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Monday, November 7, 2016 9:34 AM Subject: Re: [time-nuts

Re: [time-nuts] Thermal impact on OCXO

Hi guys, First of all, thanks for the additional responses.  I was a bit angry and rude yesterday, and I figured this thread was over.  Thanks for staying with me. I haven't had time to look over the data etc in your responses.  I'll do that and get back to the list if appropriate. I spoke to

Re: [time-nuts] Thermal impact on OCXO

V.com >> > >> > GFS GPSDO list: >> > groups.yahoo.com/neo/groups/GFS-GPSDOs/info >> > >> > From: Scott Stobbe <scott.j.sto...@gmail.com> >> > To: Bob Stewart <b...@evoria.net> >> > Cc: Discussion of Precise Time and Freque

Re: [time-nuts] Thermal impact on OCXO

yahoo.com/neo/groups/GFS-GPSDOs/info > > > > From: Scott Stobbe <scott.j.sto...@gmail.com> > > To: Bob Stewart <b...@evoria.net> > > Cc: Discussion of Precise Time and Frequency Measurement < > time-nuts@febo.com> > > Sent: Saturday, November 5, 20

Re: [time-nuts] Thermal impact on OCXO

b...@evoria.net> > Cc: Discussion of Precise Time and Frequency Measurement <time-nuts@febo.com> > Sent: Saturday, November 5, 2016 9:19 PM > Subject: Re: [time-nuts] Thermal impact on OCXO > > If your DAC spans the full EFC range than 1LSB is 1/2^20 ~ 1 PPM of the EFC > r

Re: [time-nuts] Thermal impact on OCXO

t <b...@evoria.net> > *Cc:* Discussion of Precise Time and Frequency Measurement < > time-nuts@febo.com> > *Sent:* Saturday, November 5, 2016 9:19 PM > *Subject:* Re: [time-nuts] Thermal impact on OCXO > > If your DAC spans the full EFC range than 1LSB is 1/2^20 ~ 1 PPM of

Re: [time-nuts] Thermal impact on OCXO

nd Frequency Measurement <time-nuts@febo.com> Sent: Saturday, November 5, 2016 9:43 PM Subject: Re: [time-nuts] Thermal impact on OCXO Hi If you go back to my previous list, all the things that have a tempco also age. Holding temperature over weeks or months is not at all easy ….

Re: [time-nuts] Thermal impact on OCXO

-GPSDOs/info From: Scott Stobbe <scott.j.sto...@gmail.com> To: Bob Stewart <b...@evoria.net> Cc: Discussion of Precise Time and Frequency Measurement <time-nuts@febo.com> Sent: Saturday, November 5, 2016 9:19 PM Subject: Re: [time-nuts] Thermal impact on OCXO If your

Re: [time-nuts] Thermal impact on OCXO

--- > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > > From: Bob Camp <kb...@n1k.org> > To: Bob Stewart <b...@evoria.net> > Sent: Saturday, November 5, 2016 8:46 PM > Subject: Re: [tim

Re: [time-nuts] Thermal impact on OCXO

se time and > frequency measurement <time-nuts@febo.com> > *Sent:* Saturday, November 5, 2016 8:38 PM > *Subject:* Re: [time-nuts] Thermal impact on OCXO > > I think that's a nice plot, it looks like you have stepped 160 LSB over 7 > days or roughly 1 LSB per hour. With a 20bit

Re: [time-nuts] Thermal impact on OCXO

groups/GFS-GPSDOs/info From: Bob Camp <kb...@n1k.org> To: Bob Stewart <b...@evoria.net> Sent: Saturday, November 5, 2016 8:46 PM Subject: Re: [time-nuts] Thermal impact on OCXO Hi My experience is that the aging on these oscillators is so far below a number of issues tha

Re: [time-nuts] Thermal impact on OCXO

From: Scott Stobbe <scott.j.sto...@gmail.com> To: Bob Stewart <b...@evoria.net>; Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Saturday, November 5, 2016 8:38 PM Subject: Re: [time-nuts] Thermal impact on OCXO I think that's a nice p

Re: [time-nuts] Thermal impact on OCXO

I think that's a nice plot, it looks like you have stepped 160 LSB over 7 days or roughly 1 LSB per hour. With a 20bit dac you are trimming maybe 1 ppt/LSB to 4 ppt/LSB? In allan devation terms, the case of 1ppt/LSB, solely due to drift, you're at 1E-12 at 3600*sqrt(2) = 5000 s, in the case of

Re: [time-nuts] Thermal impact on OCXO

From: Bob Camp <kb...@n1k.org> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Saturday, November 5, 2016 7:37 PM Subject: Re: [time-nuts] Thermal impact on OCXO Hi 2^20 is roughly 1 ppm. It is about 5 uV on a 5V line or 2.5 uV on

Re: [time-nuts] Thermal impact on OCXO

> > To: Discussion of precise time and frequency measurement <time-nuts@febo.com> > Sent: Saturday, November 5, 2016 7:02 PM > Subject: Re: [time-nuts] Thermal impact on OCXO > > ...with a 20bit DAC, a suitable voltage reference for that DAC and an > HP3458.

Re: [time-nuts] Thermal impact on OCXO

GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info From: Azelio Boriani <azelio.bori...@gmail.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Saturday, November 5, 2016 7:02 PM Subject: Re: [time-nuts] Thermal im

Re: [time-nuts] Thermal impact on OCXO

GPSDOs/info > > From: Hal Murray <hmur...@megapathdsl.net> > To: Bob Stewart <b...@evoria.net> > Cc: Hal Murray <hmur...@megapathdsl.net> > Sent: Saturday, November 5, 2016 6:23 PM > Subject: Re: [time-nuts] Thermal impact on OCXO > >> The OCXO has be

Re: [time-nuts] Thermal impact on OCXO

GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info From: Hal Murray <hmur...@megapathdsl.net> To: Bob Stewart <b...@evoria.net> Cc: Hal Murray <hmur...@megapathdsl.net> Sent: Saturday, November 5, 2016 6:23 PM Subject: Re: [time-nuts] Thermal impact on OCXO >

Re: [time-nuts] Thermal impact on OCXO

Oh dear.  I attached the wrong file.  Here's the correct one.  - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info ___ time-nuts mailing list -- time-nuts@febo.com

Re: [time-nuts] Thermal impact on OCXO

ise time and frequency measurement <time-nuts@febo.com> Cc: hmur...@megapathdsl.net Sent: Saturday, November 5, 2016 12:55 PM Subject: Re: [time-nuts] Thermal impact on OCXO > At 12 hours of holdover... > I think I'll need a lot more understanding of the impact of aging vs >

Re: [time-nuts] Thermal impact on OCXO

> At 12 hours of holdover... > I think I'll need a lot more understanding of the impact of aging vs > temperature At that timescale, I'd expect aging to be lost in the noise. How are you calibrating things? -- These are my opinions. I hate spam.

Re: [time-nuts] Thermal impact on OCXO

; Sent: Saturday, November 5, 2016 11:54 AM Subject: Re: [time-nuts] Thermal impact on OCXO Hi Remember - most holdover specs also include a delta temperature (like 40 to 70C) during the holdover period …. Bob > On Nov 5, 2016, at 12:15 PM, Bob Stewart <b...@evoria.net> wrote: >

Re: [time-nuts] Thermal impact on OCXO

ime-nuts@febo.com> > Sent: Saturday, November 5, 2016 10:54 AM > Subject: Re: [time-nuts] Thermal impact on OCXO > > Sounds like you already realized this. Phase is the integral of frequency and > the derivative of phase (phase rate) is frequency. So if you go from nominal >

Re: [time-nuts] Thermal impact on OCXO

t <time-nuts@febo.com> Sent: Saturday, November 5, 2016 10:54 AM Subject: Re: [time-nuts] Thermal impact on OCXO Sounds like you already realized this. Phase is the integral of frequency and the derivative of phase (phase rate) is frequency. So if you go from nominal frequenc

Re: [time-nuts] Thermal impact on OCXO

Sounds like you already realized this. Phase is the integral of frequency and the derivative of phase (phase rate) is frequency. So if you go from nominal frequency - slow - nominal or equivalently nominal frequency - fast - nominal the phase integrates up/down. It would be a little more

Re: [time-nuts] Thermal impact on OCXO

Hi You have a first order, second order and third order coefficient to the temperature rate dependance on a crystal. Since the second order term is a square, it does not care about the sign of the rate. Bob > On Nov 4, 2016, at 9:56 PM, Bob Stewart wrote: > > In the

Re: [time-nuts] Thermal impact on OCXO

On 11/4/16 6:56 PM, Bob Stewart wrote: In the general case, is the impact of changing the ambient temperature around an OCXO from, say, 40C to 41C the same as changing it from 41C to 40C all else being equal? IOW, if I somehow have the same temperature ramp over the same time period in both

Re: [time-nuts] Thermal impact on OCXO

OK, never mind.  I see the obvious.  Phase changes faster at a higher frequency than it does at a lower frequency. Bob  - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info From: Bob Stewart