Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Dan Rae]

Way back in 1960 something Braun in Germany made a little alarm clock 
using a 4.194304 MHz crystal which could reach this level of accuracy.  
I had one and it certainly met the Harrison level of timekeeping when I 
used it for navigation.  I think that the crystal cut used had a 
temperature coefficient at room temperatures that had minimal variation 
at around this frequency.   Way better than the 32+ kHz crystals used now.


The clock died in the end but I still have the crystal somewhere :^)

Dan


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Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Bob kb8tq]

HI

> On Apr 11, 2018, at 5:38 PM, Richard (Rick) Karlquist  
> wrote:
> 
> The aging spec on the 10811 is 5 parts in 10^10 per day.
> After 60 days, it could be off 30 ppb.  So what we
> have here is a non-ovenized AT cut that is better
> than an ovenized SC cut.  I'm sure.

As a practical point - they didn’t leave the factory until they hit that spec, 
Manufacturing
being what it is, having OCXO’s hang around was not a popular thing. The 
5x10^-10
per day at 5 or 10 days might well drop by quite a bit a month or two later. 
Back in the
day, this was a “who knows / who cares / meets spec” sort of thing. 

I’m not sure that everybody buys the “log rule” for aging. I think there are a 
lot of reasonable
objections to it. That aside, if there *is* a rule that applies to 80% of your 
crystals …. that’s 
doing very well. By watch standards that is “perfection”.  Measure something 
over a 10 day
period and plug that into the firmware. Yes, the watch sits in test for 10 days 
… .and you 
charge for that. 


> 
> I am reminded of the old Accutron ads.  The headlines
> guaranteed so many seconds a day or whatever it was.
> The fine print says they don't actually guarantee that.
> The only remedy under that guarantee is that they
> agree to adjust the watch to be in spec at the
> watch repair shop and hand it back to you.  Thus,
> they didn't have to worry about aging.  Just come
> into the shop as often as necessary :-)

I wonder how many watch shops are set up to re-shoot the memory in a watch CPU? 
Most of them seem to have a hard time swapping a battery and keeping things dry 
enough 
that the watch doesn’t fog up in the cold ….

Bob


> 
> Rick N6RK
> 
> On 4/11/2018 9:26 AM, tn...@joshreply.com wrote:
>> That comes out to about 30ppb, and this is a pocket watch so they don’t seem
>> to depend on the temp stabilization of being attached to a human wrist.
>>  https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
>> -Drive-Movement-04.jpg
>>  I’ve been reading about the new watch that contains this crystal for about a
>> month, but just saw some more detail today
> 
>> ---
>> AT-CUT QUARTZ CRYSTAL OSCILLATOR
>> While AT-cut quartz crystals have indeed been in production and use since as
>> early as 1934, the technology is more common in larger applications and not
>> necessarily wristwatches. To address the needs of individuals seeking only
>> the most accurate performance in a wristwatch, Citizen sought to apply and
>> optimize this available technology in a way that could serve watch consumers
>> on a more direct and personal level. When working to reach the accuracy of
>> the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
>> more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
>> variations allow for greater temperature tolerances, specifically in the
>> range of -40°C to +125°C. Additionally, this configuration allows for
>> reduced deviations caused by wearer orientation, which can cause significant
>> changes in accuracy that aren't negligible when attempting this kind of
>> performance. As a result, wearers will not have to worry about errors caused
>> by spatial orientation and positioning becomes less of a concern. The same
>> can be said about durability, which Citizen also improved upon in
>> conjunction with the AT-cut oscillator. After all, shock experienced in
>> day-to-day situations could easily prove detrimental even for quartz
>> movements. And when the goal is an annual accuracy of ±1 second, that just
>> isn't acceptable.
>>  https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/
>> ---
>>  Is this possible with an MXCO running across this wide temp range? How are
>> they compensating for aging at this level of precision?
>>  Thanks!
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Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Hal Murray]

kb...@n1k.org said:
> Before you say it can’t be done, the whole “average out” thing is how 
> time
> pieces have been done for hundreds of years. The device may swing this  way
> and that …. done properly it eventually averages out. How well it works for
> you … that depends.  

There is a wonderful message in the archives someplace that describes how to 
adjust a watch.  The recipe is roughly:
  Adjust watch to run correctly in the shop.
  Give it to customer.  Tell him to come back after a week of normal use.
  Measure offset.
  Adjust watch to compensate for that offset.

That probably doesn't work very well if your watch spends the night on the 
stand and your room temperature changes a lot from summer to winter.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Mike Cook]

I have a Citizen A660 movement which was spec’d at +/- 5 secs per year. I 
monitored it from when I bought it in December 2010 until its battery failed on 
03/11/2012. 
It was in spec when both on and off the wrist (off the wrist it was in a drawer 
at a constant temperature and the accuracy was a stability was lower) . 
The error in the first 18 months gave a yearly rate of +1,2 secs. Not bad. So 
maybe the new movement is just getting the advantage of higher frequency so 
that their cycle hops are finer grained.



> Le 11 avr. 2018 à 22:24, Bob kb8tq  a écrit :
> 
> Hi
> 
> Guess at the aging
> 
> Cut the crystal so it’s fairly flat at 25 to 35C
> 
> Do a basic / simple temperature compensation (TCXO)
> 
> …. and count on the errors to average out. 
> 
> The success of all that will depend a lot on how close your wrist is to the 
> environment they used for their guesswork. Did they count on you taking
> the watch off at night or not? What temperature is the room at? …..
> 
> Before you say it can’t be done, the whole “average out” thing is how time 
> pieces have been done for hundreds of years. The device may swing this 
> way and that …. done properly it eventually averages out. How well it works
> for you … that depends. 
> 
> Bob
> 
>> On Apr 11, 2018, at 12:26 PM, tn...@joshreply.com wrote:
>> 
>> That comes out to about 30ppb, and this is a pocket watch so they don’t seem
>> to depend on the temp stabilization of being attached to a human wrist. 
>> 
>> 
>> 
>> https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
>> -Drive-Movement-04.jpg
>> 
>> 
>> 
>> I’ve been reading about the new watch that contains this crystal for about a
>> month, but just saw some more detail today
>> 
>> 
>> ---
>> 
>> AT-CUT QUARTZ CRYSTAL OSCILLATOR
>> 
>> While AT-cut quartz crystals have indeed been in production and use since as
>> early as 1934, the technology is more common in larger applications and not
>> necessarily wristwatches. To address the needs of individuals seeking only
>> the most accurate performance in a wristwatch, Citizen sought to apply and
>> optimize this available technology in a way that could serve watch consumers
>> on a more direct and personal level. When working to reach the accuracy of
>> the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
>> more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
>> variations allow for greater temperature tolerances, specifically in the
>> range of -40°C to +125°C. Additionally, this configuration allows for
>> reduced deviations caused by wearer orientation, which can cause significant
>> changes in accuracy that aren't negligible when attempting this kind of
>> performance. As a result, wearers will not have to worry about errors caused
>> by spatial orientation and positioning becomes less of a concern. The same
>> can be said about durability, which Citizen also improved upon in
>> conjunction with the AT-cut oscillator. After all, shock experienced in
>> day-to-day situations could easily prove detrimental even for quartz
>> movements. And when the goal is an annual accuracy of ±1 second, that just
>> isn't acceptable.
>> 
>> 
>> 
>> https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/
>> 
>> ---
>> 
>> 
>> 
>> Is this possible with an MXCO running across this wide temp range? How are
>> they compensating for aging at this level of precision?
>> 
>> 
>> 
>> Thanks!
>> 
>> ___
>> 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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Don’t worry about how powerful the machines are. Worry about who the machines 
are giving  power to.

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Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Richard (Rick) Karlquist]

The aging spec on the 10811 is 5 parts in 10^10 per day.
After 60 days, it could be off 30 ppb.  So what we
have here is a non-ovenized AT cut that is better
than an ovenized SC cut.  I'm sure.

I am reminded of the old Accutron ads.  The headlines
guaranteed so many seconds a day or whatever it was.
The fine print says they don't actually guarantee that.
The only remedy under that guarantee is that they
agree to adjust the watch to be in spec at the
watch repair shop and hand it back to you.  Thus,
they didn't have to worry about aging.  Just come
into the shop as often as necessary :-)

Rick N6RK

On 4/11/2018 9:26 AM, tn...@joshreply.com wrote:

That comes out to about 30ppb, and this is a pocket watch so they don’t seem
to depend on the temp stabilization of being attached to a human wrist.

  


https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
-Drive-Movement-04.jpg

  


I’ve been reading about the new watch that contains this crystal for about a
month, but just saw some more detail today…

---

AT-CUT QUARTZ CRYSTAL OSCILLATOR

While AT-cut quartz crystals have indeed been in production and use since as
early as 1934, the technology is more common in larger applications and not
necessarily wristwatches. To address the needs of individuals seeking only
the most accurate performance in a wristwatch, Citizen sought to apply and
optimize this available technology in a way that could serve watch consumers
on a more direct and personal level. When working to reach the accuracy of
the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
variations allow for greater temperature tolerances, specifically in the
range of -40°C to +125°C. Additionally, this configuration allows for
reduced deviations caused by wearer orientation, which can cause significant
changes in accuracy that aren't negligible when attempting this kind of
performance. As a result, wearers will not have to worry about errors caused
by spatial orientation and positioning becomes less of a concern. The same
can be said about durability, which Citizen also improved upon in
conjunction with the AT-cut oscillator. After all, shock experienced in
day-to-day situations could easily prove detrimental even for quartz
movements. And when the goal is an annual accuracy of ±1 second, that just
isn't acceptable.

  


https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/

---

  


Is this possible with an MXCO running across this wide temp range? How are
they compensating for aging at this level of precision?

  


Thanks!

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Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Bob kb8tq]

Hi

Guess at the aging

Cut the crystal so it’s fairly flat at 25 to 35C

Do a basic / simple temperature compensation (TCXO)

…. and count on the errors to average out. 

The success of all that will depend a lot on how close your wrist is to the 
environment they used for their guesswork. Did they count on you taking
the watch off at night or not? What temperature is the room at? …..

Before you say it can’t be done, the whole “average out” thing is how time 
pieces have been done for hundreds of years. The device may swing this 
way and that …. done properly it eventually averages out. How well it works
for you … that depends. 

Bob

> On Apr 11, 2018, at 12:26 PM, tn...@joshreply.com wrote:
> 
> That comes out to about 30ppb, and this is a pocket watch so they don’t seem
> to depend on the temp stabilization of being attached to a human wrist. 
> 
> 
> 
> https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
> -Drive-Movement-04.jpg
> 
> 
> 
> I’ve been reading about the new watch that contains this crystal for about a
> month, but just saw some more detail today
> 
> 
> ---
> 
> AT-CUT QUARTZ CRYSTAL OSCILLATOR
> 
> While AT-cut quartz crystals have indeed been in production and use since as
> early as 1934, the technology is more common in larger applications and not
> necessarily wristwatches. To address the needs of individuals seeking only
> the most accurate performance in a wristwatch, Citizen sought to apply and
> optimize this available technology in a way that could serve watch consumers
> on a more direct and personal level. When working to reach the accuracy of
> the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
> more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
> variations allow for greater temperature tolerances, specifically in the
> range of -40°C to +125°C. Additionally, this configuration allows for
> reduced deviations caused by wearer orientation, which can cause significant
> changes in accuracy that aren't negligible when attempting this kind of
> performance. As a result, wearers will not have to worry about errors caused
> by spatial orientation and positioning becomes less of a concern. The same
> can be said about durability, which Citizen also improved upon in
> conjunction with the AT-cut oscillator. After all, shock experienced in
> day-to-day situations could easily prove detrimental even for quartz
> movements. And when the goal is an annual accuracy of ±1 second, that just
> isn't acceptable.
> 
> 
> 
> https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/
> 
> ---
> 
> 
> 
> Is this possible with an MXCO running across this wide temp range? How are
> they compensating for aging at this level of precision?
> 
> 
> 
> Thanks!
> 
> ___
> 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] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[Poul-Henning Kamp]

In message <02d201d3d1b1$d7318640$859492c0$@joshreply.com>, tn...@joshreply.com 
writes:

>That comes out to about 30ppb, and this is a pocket watch so they don't seem
>to depend on the temp stabilization of being attached to a human wrist. 

For an application where neither phase noise nor jitter matters,
it is certainly feasible to measure the tempco of the X-tal at the
factory and let a micro-power computer use temperature measurements
to model the "perfect" frequency and phase.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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[time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

[tnuts]

That comes out to about 30ppb, and this is a pocket watch so they don’t seem
to depend on the temp stabilization of being attached to a human wrist. 

 

https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco
-Drive-Movement-04.jpg

 

I’ve been reading about the new watch that contains this crystal for about a
month, but just saw some more detail today…

---

AT-CUT QUARTZ CRYSTAL OSCILLATOR

While AT-cut quartz crystals have indeed been in production and use since as
early as 1934, the technology is more common in larger applications and not
necessarily wristwatches. To address the needs of individuals seeking only
the most accurate performance in a wristwatch, Citizen sought to apply and
optimize this available technology in a way that could serve watch consumers
on a more direct and personal level. When working to reach the accuracy of
the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a
more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut
variations allow for greater temperature tolerances, specifically in the
range of -40°C to +125°C. Additionally, this configuration allows for
reduced deviations caused by wearer orientation, which can cause significant
changes in accuracy that aren't negligible when attempting this kind of
performance. As a result, wearers will not have to worry about errors caused
by spatial orientation and positioning becomes less of a concern. The same
can be said about durability, which Citizen also improved upon in
conjunction with the AT-cut oscillator. After all, shock experienced in
day-to-day situations could easily prove detrimental even for quartz
movements. And when the goal is an annual accuracy of ±1 second, that just
isn't acceptable.

 

https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/

---

 

Is this possible with an MXCO running across this wide temp range? How are
they compensating for aging at this level of precision?

 

Thanks!

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