[time-nuts] chip scale atomic clock

Robert Lutwak Lutwak at alum.mit.edu
Sat Dec 26 17:30:08 UTC 2009


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:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
> (Business)
> >> > 
> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
> >> > (978) 232-1461                              (Desk)
> >> > (339) 927-7896                              (Mobile)
> >> > (978) 927-4099                              (Facsimile)
> >> >
> >> >
> >> >
> >> > -RL
> >> >
> >> > -----------------------
> >> > Robert Lutwak
> >> > Symmetricom - Technology Realization Center
> >> > 
> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
> (Business)
> >> > 
> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
> >> > (978) 232-1461                              (Desk)
> >> > (339) 927-7896                              (Mobile)
> >> > (978) 927-4099                              (Facsimile)
> >> > _______________________________________________
> >> > time-nuts mailing list -- time-nuts at febo.com
> >> > To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> > and follow the instructions there.
> >> >
> >>
> >>
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at febo.com
> >> To unsubscribe, go to 
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> >
> >
> >
> > -RL
> >
> > -----------------------
> > Robert Lutwak
> > Symmetricom - Technology Realization Center
> > 
> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
> (Business)
> > 
> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
> > (978) 232-1461                              (Desk)
> > (339) 927-7896                              (Mobile)
> > (978) 927-4099                              (Facsimile)
> >
> >
> >
> > -RL
> >
> > -----------------------
> > Robert Lutwak
> > Symmetricom - Technology Realization Center
> > 
> <mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
> (Business)
> > 
> <mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu (Personal)
> > (978) 232-1461                              (Desk)
> > (339) 927-7896                              (Mobile)
> > (978) 927-4099                              (Facsimile)
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at 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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-RL

-----------------------
Robert Lutwak
Symmetricom - Technology Realization Center
<mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
(Business)
<mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu 
(Personal)
(978) 232-1461                              (Desk)
(339) 927-7896                              (Mobile)
(978) 927-4099                              (Facsimile)



-RL

-----------------------
Robert Lutwak
Symmetricom - Technology Realization Center
<mhtml:mid://00000000/mailto:RLutwak@Symmetricom.com>RLutwak at Symmetricom.com 
(Business)
<mhtml:mid://00000000/mailto:Lutwak@Alum.mit.edu>Lutwak at Alum.mit.edu 
(Personal)
(978) 232-1461                              (Desk)
(339) 927-7896                              (Mobile)
(978) 927-4099                              (Facsimile)


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