Notwithstanding the performance of one physics package, I think it's
safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
That figure (5B) shows the Allan deviation of 10 physics packages
(measured with optimal laboratory electronics) and you are correct
that the best of the bunch is down around 2-3e-11 at 1-second. At
that time, with low-power CSAC electronics, the performance of that
same physics package was up around 1e-10 and most were in the 2-3e-10
range (see Figure 6), which would have led to a spec somewhere north
of there, perhaps 3-4e-10.
For your amusement, I just added a more recent paper (from the 2009
FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more
recent results with (newer, better, and lower power) electronics but
similar physics package architecture. These days, typical CSAC
instability is in the range of 8-10e-11 @ 1second, which might lead
to a spec in the 1-3e-10 range.
-RL
At 11:41 AM 12/26/2009, you wrote:
Hi
I *knew* I'd seen a chart somewhere that was getting close to
1x10-11 at 1 second for the best of the group.
It's figure B on page 7 of your FSM 2008 paper.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
> I pay pretty close attention to what people in this field are
saying, and I've never heard anyone say "we'll get to 1e-11 short
term stability at 1 second real soon now."
>
> 1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or
PRS10). There are good (physics) reasons why those units all draw
100X more power than a CSAC.
>
> CSAC is intended for portable battery-powered operation. Surely
your basement has the space and wallplug power to support an LPRO.
(p.s. don't cool the damn thing, heat it).
>
> The cats were much happier during the CsIII development (see
http://home.comcast.net/~rlutwak). It was bigger and warmer. Any
Cat-Nuts out there who can help me find one with significantly lower SWAP?
>
> -RL
>
> At 10:08 AM 12/26/2009, you wrote:
>> Hi
>>
>> 1x10-11 at 1 second, going down by tau^0.5.
>>
>> That makes them candidates for the basement system ....
>>
>> Bob
>>
>> On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
>>
>> > How "good" do you want?
>> >
>> >
>> > At 09:13 AM 12/26/2009, you wrote:
>> >> Hi
>> >>
>> >> They still seem to be at the stage of "we'll get to good
short term stability at 1 second real soon now".
>> >>
>> >> Bob
>> >>
>> >>
>> >> On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
>> >>
>> >> > I read about this a while ago. Has anyone seen anything recent about
>> >> > it, notably desktop or even portable units?
>> >> > Ronald
>> >> >
>> >> > _______________________________________________
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>> >>
>> >>
>> >> _______________________________________________
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>> >
>> >
>> >
>> > -RL
>> >
>> > -----------------------
>> > Robert Lutwak
>> > Symmetricom - Technology Realization Center
>> >
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
>> >
<mhtml:mid://00000000/mailto:[email protected]>[email protected] (Personal)
>> > (978) 232-1461 (Desk)
>> > (339) 927-7896 (Mobile)
>> > (978) 927-4099 (Facsimile)
>> >
>> >
>> >
>> > -RL
>> >
>> > -----------------------
>> > Robert Lutwak
>> > Symmetricom - Technology Realization Center
>> >
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
>> >
<mhtml:mid://00000000/mailto:[email protected]>[email protected] (Personal)
>> > (978) 232-1461 (Desk)
>> > (339) 927-7896 (Mobile)
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>
>
>
> -RL
>
> -----------------------
> Robert Lutwak
> Symmetricom - Technology Realization Center
>
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
>
<mhtml:mid://00000000/mailto:[email protected]>[email protected] (Personal)
> (978) 232-1461 (Desk)
> (339) 927-7896 (Mobile)
> (978) 927-4099 (Facsimile)
>
>
>
> -RL
>
> -----------------------
> Robert Lutwak
> Symmetricom - Technology Realization Center
>
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
>
<mhtml:mid://00000000/mailto:[email protected]>[email protected] (Personal)
> (978) 232-1461 (Desk)
> (339) 927-7896 (Mobile)
> (978) 927-4099 (Facsimile)
> _______________________________________________
> time-nuts mailing list -- [email protected]
> To unsubscribe, go to
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> and follow the instructions there.
>
_______________________________________________
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-RL
-----------------------
Robert Lutwak
Symmetricom - Technology Realization Center
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Personal)
(978) 232-1461 (Desk)
(339) 927-7896 (Mobile)
(978) 927-4099 (Facsimile)
-RL
-----------------------
Robert Lutwak
Symmetricom - Technology Realization Center
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Business)
<mhtml:mid://00000000/mailto:[email protected]>[email protected]
(Personal)
(978) 232-1461 (Desk)
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(978) 927-4099 (Facsimile)
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