Re: [time-nuts] Excel logarithmic function

[Charles Steinmetz]

Rick wrote:


The one thing I can say is that it is good to keep the crystal
ovenized at all times.  Even a momentary oven outage tends to
reboot aging.


That has been my observation, as well.  Same with mechanical shock and 
with interruptions of oscillation (even if the oven remains undisturbed).


Charles


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Re: [time-nuts] Excel logarithmic function (was Thermal impact on OCXO)

[Richard (Rick) Karlquist]

On 11/24/2016 5:16 AM, Bob Camp wrote:


The biggest challenge is to take out the “early stuff”. One approach is to fit
the same equation twice with the time constant restricted to a range on each.
For most OCXO’s (90%) the equation when fit early represents an upper limit
to the drift. You might get a another element that comes in and is apparent
after a year or two. It might be replaced by another element after five or ten 
years.
They generally (~80%) represent a change in sign (negative drift vs positive).

If you look at the “other 10%” some have really poor aging and are not shipped.
Some are very erratic and simply can not be fit. Some of the 90% are fit with a
“upper limit” because they exhibit no measurable aging over the 30 days (or 
whatever)
of testing.

If you take the bad aging (out of spec) parts out of the pile, those are the 
ones
with the best fit. They have very pretty curves and they stick to those curves
for a *long* time. They have a single dominant cause for their aging ( = the 
defect).
The rest of the parts have all of the causes bashed down by the process so that
over a 20 or 30 year span, there probably is no single dominant cause.

Bob




This excellent response channels what Jack Kusters used to say.  The
idea that aging follows any predicable pattern might have been true
decades ago.  For example, I remember being told in 1974 that
everyone knew that metal crystals aged downward and glass crystals
aged upward.  It was true at the time, but those aging processes
have been beat down.  According to Jack, 10811/E1938A aging is
primarily "stress relaxation".  It could be either direction and
a given crystal can change direction over time.  On top of that,
crystals have frequency "jumps" at unpredictable intervals.  At
HP, we had an "aging system" that watched crystals to try to reject
bad actors and find the well behaved ones.  The problem was that the
longer you watched an oscillator, the better chance of catching
it in the act of jumping.  They didn't necessarily get better
over time (over many months).  No matter how many crystals we
looked at, we never found one that had atomic like aging.

My observation is that the systematic (therefore predictable)
aging processes have been eliminated by improved manufacturing
techniques, leaving the true random (unpredictable) aging
processes.

The one thing I can say is that it is good to keep the crystal
ovenized at all times.  Even a momentary oven outage tends to
reboot aging.

Rick
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Re: [time-nuts] crystal againg fit (was: Excel logarithmic function)

[Bob Camp]

Hi

> On Nov 24, 2016, at 10:49 AM, Attila Kinali  wrote:
> 
> On Thu, 24 Nov 2016 08:16:08 -0500
> Bob Camp  wrote:
> 
>> If you take the bad aging (out of spec) parts out of the pile, those are the 
>> ones
>> with the best fit. They have very pretty curves and they stick to those 
>> curves
>> for a *long* time. They have a single dominant cause for their aging ( = the 
>> defect). 
>> The rest of the parts have all of the causes bashed down by the process so 
>> that
>> over a 20 or 30 year span, there probably is no single dominant cause. 
> 
> Then the question becomes: What would be a good fitting function for
> the typical application of an OCXO that is regularly measured with
> not too long time spans (e.g. GPSDO)? From the discussion it seems
> that a second or third order Taylor would be sufficient to capture
> aging for a span of 10-100 days.

Simple answer no. More complex answer: what are you trying to do? Depending
on the answer to that there may be other functions that are useful. In general 
an unconstrained polynomial is great for fitting the data you have and awful 
for predicting the future. 

Bob

> 
>   Attila Kinali
> 
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[Bruce Griffiths]

John
Whilst its the highest resolution HP/Agilent/Keysight general purpose counter, 
one of the Acquiris timestamping instruments specifies 5ps noise.Whilst no 
detailed circuit schematics are publicly available, the datasheet says just 
enough to allow me to figure  out how they do it.Your timestamping counter fits 
nicely in the niche between these and the HP5131A at much lower cost than the 
latter.
Bruce 

On Friday, 25 November 2016 11:00 AM, John Ackermann N8UR  
wrote:
 

 Thanks, Bruce, I'll update the web page to reference the 53230A as the 
best resolution device currently available.

On 11/24/2016 01:03 PM, Bruce Griffiths wrote:
> John
>
> There is an application note or similar on the 53230A that indicates that
> the single shot noise for time interval measurement is typically about 13ps
> or so.
>
> Bruce
> On Thursday, November 24, 2016 09:43:54 AM John Ackermann N8UR
> wrote:
>> Hi Anders --
>>
>> Thanks, and thanks for the info on the 53230A.  I have not used one of
>> those myself but the data sheet lists 20ps single-shot.
>>
>> Also I should note that the TICC does not compete with counters like the
>> 53230A for high speed measurement, or frequency counting.  It does far
>> fewer measurements per second than the high-end counters -- my
> design
>> criteria was for use in PPS measuring system.
>>
>> With the current software, the actual measurement processing time is
>> about 1 millisecond; we may be able to optimize a hundred or two
>> microseconds from that as the code currently has more 64 bit
> operations
>> than are necessary, and there are other things that can surely be
> tweaked.
>>
>> The killer is the serial output via USB.  It can take up to 10 ms to
>> output 20 characters, and that's what really limits the measurement
>> rate.  I'm pretty sure this can be improved (one idea is to buffer
>> results to reduce USB packetization delays), but there's other
>> functionality that I need to finish first.
>>
>> BTW -- the software is open source and on github at
>> https://github.com/TAPR/TICC , so I welcome anyone who wants to work
> on
>> it.  Bug fixes are gladly accepted, and if you're looking for work to
>> do, I could use a volunteer to work on a couple of areas, most
>> critically finishing a UI that will allow the user to set operating
>> parameters.
>>
>> John
>> 
>>
>> On 11/24/2016 02:40 AM, Anders Wallin wrote:
>>> Nice work!
>>> On the website in the introduction you mention 22ps single-shot
>>> time-stamping on the 5370A/B.
>>> I think it's well established that the 53230A does about 11-12 ps for
>>> time-intervals, which corresponds to about 9 ps single-channel. see
> for
>>> example:
>>> http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
>>>
>>> Anders
>>>
>>>
>>> On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince
> 
>>>
>>> wrote:
 Fantastic John - well done!  Yes, I'll definitely put an order in as soon
 as possible.

        Regards,

            Peter  (G8ZZR, London)

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>>>
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>>
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Re: [time-nuts] crystal againg fit (was: Excel logarithmic function)

[Bob Camp]

Hi

There *has* been a lot of research into these functions. The Frequency Control
Symposium archives have at least a few dozen papers on the why and how
of the functions working. They are now behind a paywall for me so those who have
the luxury of access will have to dig for them on their own.

Bob


> On Nov 24, 2016, at 5:03 PM, Scott Stobbe  wrote:
> 
> Sadly I don't think there is a concise answer to this, in reality you would
> make the decision on the fly depending on how much data you have and which
> model is the most well behaved.
> 
> I think it's a really interesting topic to see some of what goes into an
> OCXO, a guaranteed limit on aging is one the many things.
> 
> Part of the reason that information on the topic is somewhat is scattered,
> is if a commercial application genuinely needed 1e-12 stability for 100
> days free-running, the answer without hesitation would be atomic. Then as
> you dial back the long-term stability requirement how much NRE are you
> willing to spend; which is also why there doesn't seem to plenty of worked
> examples out there.
> 
> On Thu, Nov 24, 2016 at 10:49 AM, Attila Kinali  wrote:
> 
>> On Thu, 24 Nov 2016 08:16:08 -0500
>> Bob Camp  wrote:
>> 
>>> If you take the bad aging (out of spec) parts out of the pile, those are
>> the ones
>>> with the best fit. They have very pretty curves and they stick to those
>> curves
>>> for a *long* time. They have a single dominant cause for their aging ( =
>> the defect).
>>> The rest of the parts have all of the causes bashed down by the process
>> so that
>>> over a 20 or 30 year span, there probably is no single dominant cause.
>> 
>> Then the question becomes: What would be a good fitting function for
>> the typical application of an OCXO that is regularly measured with
>> not too long time spans (e.g. GPSDO)? From the discussion it seems
>> that a second or third order Taylor would be sufficient to capture
>> aging for a span of 10-100 days.
>> 
>>Attila Kinali
>> 
>> --
>> It is upon moral qualities that a society is ultimately founded. All
>> the prosperity and technological sophistication in the world is of no
>> use without that foundation.
>> -- Miss Matheson, The Diamond Age, Neil Stephenson
>> ___
>> 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.
>> 
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Thanks, Bruce, I'll update the web page to reference the 53230A as the 
best resolution device currently available.


On 11/24/2016 01:03 PM, Bruce Griffiths wrote:

John

There is an application note or similar on the 53230A that indicates that
the single shot noise for time interval measurement is typically about 13ps
or so.

Bruce
On Thursday, November 24, 2016 09:43:54 AM John Ackermann N8UR
wrote:

Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of
those myself but the data sheet lists 20ps single-shot.

Also I should note that the TICC does not compete with counters like the
53230A for high speed measurement, or frequency counting.  It does far
fewer measurements per second than the high-end counters -- my

design

criteria was for use in PPS measuring system.

With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit

operations

than are necessary, and there are other things that can surely be

tweaked.


The killer is the serial output via USB.  It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate.  I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.

BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work

on

it.  Bug fixes are gladly accepted, and if you're looking for work to
do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.

John


On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see

for

example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince




wrote:

Fantastic John - well done!  Yes, I'll definitely put an order in as soon
as possible.

   Regards,

   Peter  (G8ZZR, London)

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[time-nuts] Happy Thanksgiving...

[Burt I. Weiner]

Gang,

Just a quick not to wish all of you a Happy 
Thanksgiving.  Thanksgiving is the best of the Holidays; a time to 
give thanks for them many blessings we have and to be with those who 
are most important to us.  May all of your standards and time pieces agree.


Enjoy,

Burt, K6OQK

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
b...@att.net
K6OQK 


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[time-nuts] New Timestamping / Time Interval Counter: the TICC

[Mark Sims]

I might be able to add support to Lady Heather.Lady Heather does have code 
for calculating and displaying ADEV, HDEV, MDEV, and TDEV (it came from 
Timelab).  Also has data logging capabilities.  And can also calculate FFTs of 
the data.  It can already read Timelab .TIM files.


--

>  I could use a volunteer to work on a couple of areas, most 
critically finishing a UI that will allow the user to set operating 
parameters.
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[jimlux]

On 11/24/16 6:43 AM, John Ackermann N8UR wrote:

Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of
those myself but the data sheet lists 20ps single-shot.

Also I should note that the TICC does not compete with counters like the
53230A for high speed measurement, or frequency counting.  It does far
fewer measurements per second than the high-end counters -- my design
criteria was for use in PPS measuring system.

With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit operations
than are necessary, and there are other things that can surely be tweaked.

The killer is the serial output via USB.  It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate.  I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.


2000 bytes/second

A "arduino compatible" processor might help.. The teensy easily pumps 6 
kbytes/second over USB in 64 byte chunks - but the Freescale processor 
has a hardware USB buffer thing.








BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work on
it.  Bug fixes are gladly accepted, and if you're looking for work to
do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.

John

On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png


Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 
wrote:


Fantastic John - well done!  Yes, I'll definitely put an order in as
soon
as possible.

  Regards,

  Peter  (G8ZZR, London)
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[Bruce Griffiths]

John

There is an application note or similar on the 53230A that indicates that 
the single shot noise for time interval measurement is typically about 13ps 
or so.

Bruce
On Thursday, November 24, 2016 09:43:54 AM John Ackermann N8UR 
wrote:
> Hi Anders --
> 
> Thanks, and thanks for the info on the 53230A.  I have not used one of
> those myself but the data sheet lists 20ps single-shot.
> 
> Also I should note that the TICC does not compete with counters like the
> 53230A for high speed measurement, or frequency counting.  It does far
> fewer measurements per second than the high-end counters -- my 
design
> criteria was for use in PPS measuring system.
> 
> With the current software, the actual measurement processing time is
> about 1 millisecond; we may be able to optimize a hundred or two
> microseconds from that as the code currently has more 64 bit 
operations
> than are necessary, and there are other things that can surely be 
tweaked.
> 
> The killer is the serial output via USB.  It can take up to 10 ms to
> output 20 characters, and that's what really limits the measurement
> rate.  I'm pretty sure this can be improved (one idea is to buffer
> results to reduce USB packetization delays), but there's other
> functionality that I need to finish first.
> 
> BTW -- the software is open source and on github at
> https://github.com/TAPR/TICC , so I welcome anyone who wants to work 
on
> it.  Bug fixes are gladly accepted, and if you're looking for work to
> do, I could use a volunteer to work on a couple of areas, most
> critically finishing a UI that will allow the user to set operating
> parameters.
> 
> John
> 
> 
> On 11/24/2016 02:40 AM, Anders Wallin wrote:
> > Nice work!
> > On the website in the introduction you mention 22ps single-shot
> > time-stamping on the 5370A/B.
> > I think it's well established that the 53230A does about 11-12 ps for
> > time-intervals, which corresponds to about 9 ps single-channel. see 
for
> > example:
> > http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png
> > 
> > Anders
> > 
> > 
> > On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 

> > 
> > wrote:
> >> Fantastic John - well done!  Yes, I'll definitely put an order in as soon
> >> as possible.
> >> 
> >>   Regards,
> >>   
> >>   Peter  (G8ZZR, London)
> >> 
> >> ___
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[time-nuts] SYMMETRICON GPS Package For Sale

[Richard W. Solomon]

I bought these a while ago, but never got to put them in service:

 

Box #1: Z3811A, Rev A, w/Z3809A Cable (LUC SEC BD)

 

Box #2: Z3812A, Rev A (LUC PRI BD)

 

Boxes were opened to verify contents, but inner packing untouched.

 

Both for $150 (or best offer) plus shipping from 85641 (Arizona). 

 

Tnx es HH, Dick, W1KSZ 

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[time-nuts] crystal againg fit (was: Excel logarithmic function)

[Attila Kinali]

On Thu, 24 Nov 2016 08:16:08 -0500
Bob Camp  wrote:

> If you take the bad aging (out of spec) parts out of the pile, those are the 
> ones
> with the best fit. They have very pretty curves and they stick to those curves
> for a *long* time. They have a single dominant cause for their aging ( = the 
> defect). 
> The rest of the parts have all of the causes bashed down by the process so 
> that
> over a 20 or 30 year span, there probably is no single dominant cause. 

Then the question becomes: What would be a good fitting function for
the typical application of an OCXO that is regularly measured with
not too long time spans (e.g. GPSDO)? From the discussion it seems
that a second or third order Taylor would be sufficient to capture
aging for a span of 10-100 days.

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Thanks, Andrew.  Yes, it is weird how the Arduino folks choose what 
capabilities to expose on the board.  From some testing I did, it seems 
that the Arduino handles the 100 kHz interrupt rate without too much 
strain -- it became a bigger issue at 250 kHz or above -- but the timers 
would have been a more elegant approach if they had been available.


John


On 11/24/2016 02:49 AM, Andrew Rodland wrote:

On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR  wrote:

The TICC is implemented as a two-channel timestamping counter.  That means
it can measure one or two low-frequency (e.g., pulse-per-second) inputs
against an external 10 MHz reference, or it can do a traditional time
interval measurement of one input against the other.  It can also measure
period, ratio, or any other function of two-channel  timestamp data.  (And
by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more
synchronized channels, though we haven't tested this capability yet.)


Very exciting, I will definitely be wanting one :)

There's *almost* a way to do the coarse timer counting with almost no
CPU overhead, but unfortunately the Arduino folks were terribly
inconsistent about which timer signals they decided to assign to
Arduino pins. Of the six external clocks for timers, they brought out
two (T0 and T5), and of the four input captures, they brought out two
(ICP4 and ICP5). If they had brought out T4 then with a little bit of
timer configuration you could use COARSE to clock TIMER4 and TIMER5 in
lockstep, run STOP_A and STOP_B to ICP4 and ICP5, and instead of
interrupting at 10kHz to increment PICcount, you would only have to
interrupt every 6.5536 seconds to increment the upper bits. Plus
handling the actual events of course. I find that very appealing, but
unfortunately, T4 is out of reach of a shield.

Andrew
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of 
those myself but the data sheet lists 20ps single-shot.


Also I should note that the TICC does not compete with counters like the 
53230A for high speed measurement, or frequency counting.  It does far 
fewer measurements per second than the high-end counters -- my design 
criteria was for use in PPS measuring system.


With the current software, the actual measurement processing time is 
about 1 millisecond; we may be able to optimize a hundred or two 
microseconds from that as the code currently has more 64 bit operations 
than are necessary, and there are other things that can surely be tweaked.


The killer is the serial output via USB.  It can take up to 10 ms to 
output 20 characters, and that's what really limits the measurement 
rate.  I'm pretty sure this can be improved (one idea is to buffer 
results to reduce USB packetization delays), but there's other 
functionality that I need to finish first.


BTW -- the software is open source and on github at 
https://github.com/TAPR/TICC , so I welcome anyone who wants to work on 
it.  Bug fixes are gladly accepted, and if you're looking for work to 
do, I could use a volunteer to work on a couple of areas, most 
critically finishing a UI that will allow the user to set operating 
parameters.


John

On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 
wrote:


Fantastic John - well done!  Yes, I'll definitely put an order in as soon
as possible.

  Regards,

  Peter  (G8ZZR, London)
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Re: [time-nuts] Excel logarithmic function (was Thermal impact on OCXO)

[Bob Camp]

Hi


> On Nov 23, 2016, at 11:21 PM, Scott Stobbe  wrote:
> 
> Hi Lars,
> 
> There are a few other pieces I have yet to fully appreciate. One of which
> is that Aln(Bt+1) isn't a time-invariant model. In the most common case
> (for the mfg) the time scale aligns with infancy of the OCXO, when it's hot
> off the line. However after pre-aging, perhaps some service life, what time
> reference is best? Sometime I will try adding an additional parameter for
> infancy time and see how that goes.


The biggest challenge is to take out the “early stuff”. One approach is to fit 
the same equation twice with the time constant restricted to a range on each.
For most OCXO’s (90%) the equation when fit early represents an upper limit
to the drift. You might get a another element that comes in and is apparent 
after a year or two. It might be replaced by another element after five or ten 
years.
They generally (~80%) represent a change in sign (negative drift vs positive). 

If you look at the “other 10%” some have really poor aging and are not shipped. 
Some are very erratic and simply can not be fit. Some of the 90% are fit with a
“upper limit” because they exhibit no measurable aging over the 30 days (or 
whatever)
of testing. 

If you take the bad aging (out of spec) parts out of the pile, those are the 
ones
with the best fit. They have very pretty curves and they stick to those curves
for a *long* time. They have a single dominant cause for their aging ( = the 
defect). 
The rest of the parts have all of the causes bashed down by the process so that
over a 20 or 30 year span, there probably is no single dominant cause. 

Bob

> 
> A fit of the full ten year data-set, attached in the two plots
> "Lars_10Year.png", "Lars_10Year_45Day.png".
> 
> I would agree to your description of 1/sqrt(t) aging for the first 1000
> days, but sometime after, it follows 1/t. Attached is plot of age rate
> "Lars_AgeRate.png". You can see during the first 1000 days the age rate
> declines at 1 decade for 2 decades time indicating t^(-1/2), but eventually
> it follows 1/t.
> 
> On Wed, Nov 23, 2016 at 3:57 PM, Lars Walenius 
> wrote:
> 
>> Hi Scott.
>> 
>> 
>> 
>> Here is a textfile with data for the 10 years (As in the graph 2001-2011).
>> 
>> 
>> 
>> Also the ln(bt+1) fit, as Magnus said, has the derivate b/(b*t+1) that
>> with b*t >>1 is 1/t. But my data has the aging between 1 and 10 years more
>> like 1/sqrt(t) If I just have a brief look on the aging graph.
>> 
>> 
>> 
>> Lars
>> 
>> 
>> 
>> *Från: *Scott Stobbe 
>> *Skickat: *den 19 november 2016 04:11
>> 
>> Hi Lars,
>> 
>> 
>> 
>> I agree with you, that if there is data out there, it isn't easy to find,
>> 
>> many thanks for sharing!
>> 
>> 
>> 
>> Fitting to the full model had limited improvements, the b coefficient was
>> 
>> quite large making it essentially equal to the ln(x) function you fitted in
>> 
>> excel. It is attached as "Lars_FitToMil55310.png".
>> 
>> 
>> 
>> So on further thought, the B term can't model a device aging even faster
>> 
>> than it should shortly after infancy. In the two extreme cases either B is
>> 
>> large and (Bt)>>1 so the be B term ends up just being an additive bias, or
>> 
>> B is small, and ln(x) is linearized (or slowed down) during the first bit
>> 
>> of time.
>> 
>> 
>> 
>> You can approximated the MIL 55310 between two points in time as
>> 
>> 
>> 
>> f(t2) - f(t1) = Aln(t2/t1)
>> 
>> 
>> 
>> A = ( f(t2) - f(t1) )/ln(t2/t1)
>> 
>> 
>> 
>> Looking at some of your plots it looks like between the end of year 1 and
>> 
>> year 10 you age from 20 ppb to 65 ppb,
>> 
>> 
>> 
>> A ~ 20
>> 
>> 
>> 
>> The next plot "Lars_ForceAcoef", is a fit with the A coefficient forced to
>> 
>> be 2 and 20. The 20 doesn't end-up fitting well on this time scale.
>> 
>> 
>> 
>> Looking at the data a little more, I wondered if the first 10 day are going
>> 
>> through some behavior that isn't representative of long-term aging, like
>> 
>> warm-up, retrace (I'm sure bob could name half a dozen more examples). So
>> 
>> the next two plots are fits of the 4 data points after day10, and seem to
>> 
>> fit well, "Lars_FitAfterDay10.png", "Lars_1Year.png".
>> 
>> 
>> 
>> If you are willing to share the next month, we can add that to the fit.
>> 
>> 
>> 
>> Cheers,
>> 
>> 
>> 
>> On Fri, Nov 18, 2016 at 1:26 PM, Lars Walenius 
>> 
>> wrote:
>> 
>>> 
>> 
>>> Hopefully someone can find the correct a and b for a*ln(bt+1) with
>> 
>> stable32 or matlab for this data set:
>> 
>>> Days ppb
>> 
>>> 2   2
>> 
>>> 4   3.5
>> 
>>> 7   4.65
>> 
>>> 8   5.05
>> 
>>> 9   5.22
>> 
>>> 12 6.11
>> 
>>> 13 6.19
>> 
>>> 25 7.26
>> 
>>> 32 7.92
>> 
>> 
>> 
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Re: [time-nuts] How can I measure GPS Antenna quality?

[David J Taylor]

From: Mark Sims

Yes.  It also works with GPSD so should be able to work with any device that 
GPSD supports.  It also works with most common GPS receiver native binary 
languages and provides full device control.


---

Thanks, Mark.  I look forward to playing with a copy.  I have a Garmin GPS 
60 CSx with Franson GPSgate turning its USB stream into a virtual COM5.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] Time, NTD, IoT and bug fixes

[David J Taylor]

Given recent discussions of IoT, NTP and wall clocks, this may be of 
interest


http://www.theregister.co.uk/2016/11/23/ntp_patch_time_rolls_around_again/

And the vulnerabilities:

http://www.kb.cert.org/vuls/id/633847

Clint.
===

Folks needing updates for Windows can get them here:

 http://www.satsignal.eu/ntp/x86/index.html

and Meinberg have updated their install program too.  I compiled the source 
on Linux for the Raspberry Pi OK, but it doesn't compile on an older Linux 
that I have on another x86 PC (which compiles the previous ntp-4.2.8p8).


Does this affect systems not serving NTP to the outside world?

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[Bruce Griffiths]

1-2ps rms single shot noise timestamping is feasible with embedded (occurs as 
part of the interpolation process) interpolator calibration. Only calibration 
of the differential delay between channels is required, as is required by all 
such instruments.
However the cost for such a timestamping counter is somewhat higher than for 
John's timestamping counter, but about a couple of orders of magnitude less 
than the final list price of a 5370B.
Bruce 

On Thursday, 24 November 2016 9:01 PM, Anders Wallin 
 wrote:
 

 Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 
wrote:

> Fantastic John - well done!  Yes, I'll definitely put an order in as soon
> as possible.
>
>      Regards,
>
>          Peter  (G8ZZR, London)
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[Anders Wallin]

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 
wrote:

> Fantastic John - well done!  Yes, I'll definitely put an order in as soon
> as possible.
>
>  Regards,
>
>  Peter  (G8ZZR, London)
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> mailman/listinfo/time-nuts
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>
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[Andrew Rodland]

On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR  wrote:
> The TICC is implemented as a two-channel timestamping counter.  That means
> it can measure one or two low-frequency (e.g., pulse-per-second) inputs
> against an external 10 MHz reference, or it can do a traditional time
> interval measurement of one input against the other.  It can also measure
> period, ratio, or any other function of two-channel  timestamp data.  (And
> by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more
> synchronized channels, though we haven't tested this capability yet.)

Very exciting, I will definitely be wanting one :)

There's *almost* a way to do the coarse timer counting with almost no
CPU overhead, but unfortunately the Arduino folks were terribly
inconsistent about which timer signals they decided to assign to
Arduino pins. Of the six external clocks for timers, they brought out
two (T0 and T5), and of the four input captures, they brought out two
(ICP4 and ICP5). If they had brought out T4 then with a little bit of
timer configuration you could use COARSE to clock TIMER4 and TIMER5 in
lockstep, run STOP_A and STOP_B to ICP4 and ICP5, and instead of
interrupting at 10kHz to increment PICcount, you would only have to
interrupt every 6.5536 seconds to increment the upper bits. Plus
handling the actual events of course. I find that very appealing, but
unfortunately, T4 is out of reach of a shield.

Andrew
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