Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Should I assume from these posts that there are no portable low power commercial products better than a thermocompensated quartz watch working at ~10^-7? Ronald On Sat, Dec 26, 2009 at 1:09 PM, wrote: > Send time-nuts mailing list submissions to > time-n...@febo.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > time-nuts-requ...@febo.com > > You can reach the person managing the list at > time-nuts-ow...@febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Re: chip scale atomic clock (Robert Lutwak) > 2. Re: Cheap Rubidium (Bob Camp) > 3. Re: chip scale atomic clock (paul swed) > 4. Re: chip scale atomic clock (Bob Camp) > > > -- > > Message: 1 > Date: Sat, 26 Dec 2009 12:30:08 -0500 > From: Robert Lutwak > Subject: Re: [time-nuts] chip scale atomic clock > To: Discussion of precise time and frequency measurement > > Message-ID: > Content-Type: text/plain; charset="us-ascii"; format=flowed > > 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 >> >> >> > >> >> >> > ___ >> >> >> > 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. >> >> >> > >> >> >> >> >> >> >> >> >> ___ >> >> >> 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. >> >> > >> >> > >> >> > >> >> > -RL >> >> > >> >> > --- >> >> > Robert Lutwak >> >> > Symmetricom - Technology Realization Center >> >> > >> mailto:rlut...@symmetricom.com>rlut...@symmetricom.com >> (Business) >> >> > >> mailto:lut...@alum.mit.edu>lut...@alum.mit.edu >> (Personal) >> >> > (978) 232-1461
Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Hi A lot depends on your definition of low power. To some an EMXO is low power, to other's it's grossly high power. People have indeed rigged up portable rubidiums with battery packs. I would not call them low power, but they are portable. If the microamp current drain of a quartz watch at a bit over a volt is the standard of low power, then the answer is no. There's nothing lower power than that with better accuracy. As always the answer is indeed that depends ... 1) How big / heavy / rugged? 2) How long does it operate on it's own? 3) What's the temperature range and the rest of the environment? 4) How accurate do you need? 5) Does it need to be autonomous? Tough to beat a self winding quartz wrist watch, unless it's not accurate enough to do what you need to do. Bob On Dec 26, 2009, at 5:25 PM, Ronald Held wrote: > Should I assume from these posts that there are no portable low power > commercial products better than a thermocompensated quartz watch > working at ~10^-7? > > Ronald > > On Sat, Dec 26, 2009 at 1:09 PM, wrote: >> Send time-nuts mailing list submissions to >>time-nuts@febo.com >> >> To subscribe or unsubscribe via the World Wide Web, visit >>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> or, via email, send a message with subject or body 'help' to >>time-nuts-requ...@febo.com >> >> You can reach the person managing the list at >>time-nuts-ow...@febo.com >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of time-nuts digest..." >> >> >> Today's Topics: >> >> 1. Re: chip scale atomic clock (Robert Lutwak) >> 2. Re: Cheap Rubidium (Bob Camp) >> 3. Re: chip scale atomic clock (paul swed) >> 4. Re: chip scale atomic clock (Bob Camp) >> >> >> -- >> >> Message: 1 >> Date: Sat, 26 Dec 2009 12:30:08 -0500 >> From: Robert Lutwak >> Subject: Re: [time-nuts] chip scale atomic clock >> To: Discussion of precise time and frequency measurement >> >> Message-ID: >> Content-Type: text/plain; charset="us-ascii"; format=flowed >> >> 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 any
Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Hi, 2009/12/27 Bob Camp : > Tough to beat a self winding quartz wrist watch, unless it's not accurate > enough to do what you need to do. And perhaps that's the point we sometimes miss. 73 Steve -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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.
Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Hi But being *rational* about all this takes out most of the fun Bob On Dec 28, 2009, at 5:30 AM, Steve Rooke wrote: > Hi, > > 2009/12/27 Bob Camp : > >> Tough to beat a self winding quartz wrist watch, unless it's not accurate >> enough to do what you need to do. > > And perhaps that's the point we sometimes miss. > > 73 > Steve > -- > Steve Rooke - ZL3TUV & G8KVD > A man with one clock knows what time it is; > A man with two clocks is never quite sure. > > ___ > 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. > ___ 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.
Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
> Tough to beat a self winding quartz wrist watch, unless it's not > accurate enough to do what you need to do. I thought the self-winding watches were mechanical and that quartz watches ran off batteries. Did I miss something? -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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.
Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Hi There is a sub-species of quartz watch that is indeed self winding. Seiko makes them in competition to Citizen's solar charging quartz watches. Bob On Dec 28, 2009, at 2:00 PM, Hal Murray wrote: > >> Tough to beat a self winding quartz wrist watch, unless it's not >> accurate enough to do what you need to do. > > I thought the self-winding watches were mechanical and that quartz watches > ran off batteries. > > Did I miss something? > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > ___ > 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. > ___ 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.
