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Discussion of precise time and frequency measurement

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statistical distribution of initial frequency error in tcxos

BK
Bob kb8tq
Thu, Mar 14, 2019 12:30 AM

Hi

If you have something in the 100’s of these “up there” with things like doppler / temperature /
radiation / and aging all involved ….. how different do they need to be in order for the initial
delta frequency to be useful / good enough ?

I can see a pretty good argument that something past the “couple of ppm” might be needed.
On a hundred devices that comes out to a pretty big spread.

Bob

On Mar 13, 2019, at 7:03 PM, jimlux jimlux@earthlink.net wrote:

On 3/13/19 2:28 PM, wb6bnq wrote:

Hi Jim,
If you have a mother-ship and presuming that it is going to be within "RF" range of all little ones, how about sending a "PILOT" tone that comes from the mother-ship to phase lock all the little ones internal oscillators ???

That's basically the idea. But you need multiple source locations at multiple frequencies to solve for position, velocity, and local clock offset.

The process is very much like GPS (or Transit) but, of course, there is no GPS in deep space.

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Hi If you have something in the 100’s of these “up there” with things like doppler / temperature / radiation / and aging all involved ….. how different do they need to be in order for the initial delta frequency to be useful / good enough ? I can see a pretty good argument that something past the “couple of ppm” might be needed. On a hundred devices that comes out to a pretty big spread. Bob > On Mar 13, 2019, at 7:03 PM, jimlux <jimlux@earthlink.net> wrote: > > On 3/13/19 2:28 PM, wb6bnq wrote: >> Hi Jim, >> If you have a mother-ship and presuming that it is going to be within "RF" range of all little ones, how about sending a "PILOT" tone that comes from the mother-ship to phase lock all the little ones internal oscillators ??? > > That's basically the idea. But you need multiple source locations at multiple frequencies to solve for position, velocity, and local clock offset. > > The process is very much like GPS (or Transit) but, of course, there is no GPS in deep space. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.
PK
Poul-Henning Kamp
Thu, Mar 14, 2019 7:02 AM

On 3/13/19 9:17 AM, Attila Kinali wrote:

(recognizing that I can probably do something like modulate the
reference broadcast with a single bit from some existing part and do
CDMA in some form - but it was a thought..)

Do they have to transmit continuously, our could you use a dutycycle
of, say 10%, to reduce the problem to something more manageable ?

Obviously that introduces cycle-slips into the math...

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@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.

-------- In message <583f5f3f-6b56-1255-4e6d-afd465cc4b37@earthlink.net>, jimlux writes: >On 3/13/19 9:17 AM, Attila Kinali wrote: >(recognizing that I can probably do something like modulate the >reference broadcast with a single bit from some existing part and do >CDMA in some form - but it was a thought..) Do they have to transmit continuously, our could you use a dutycycle of, say 10%, to reduce the problem to something more manageable ? Obviously that introduces cycle-slips into the math... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@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.
AG
Achim Gratz
Thu, Mar 14, 2019 6:44 PM

jimlux writes:

Here's the application:
100 (or 1000) independent nodes (in space, as it happens) - I want to
calculate the probability that two nodes are within some delta f of
each other.

Provided I get correctly what you are trying to do: perhaps it would be
easier to take one of the programmable MEMS oscillators (and get a
programmer or find someone who can do that for you) and just trim each
of them the way you want it to.

Regards,
Achim.

+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Factory and User Sound Singles for Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds

jimlux writes: > Here's the application: > 100 (or 1000) independent nodes (in space, as it happens) - I want to > calculate the probability that two nodes are within some delta f of > each other. Provided I get correctly what you are trying to do: perhaps it would be easier to take one of the programmable MEMS oscillators (and get a programmer or find someone who can do that for you) and just trim each of them the way you want it to. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ Factory and User Sound Singles for Waldorf Blofeld: http://Synth.Stromeko.net/Downloads.html#WaldorfSounds
BC
Bob Camp
Thu, Mar 14, 2019 9:54 PM

Hi

I think the gotcha there is the need for “very good phase noise”.

Bob

From: Achim Gratz
Sent: Thursday, March 14, 2019 5:05 PM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] statistical distribution of initial frequency errorin tcxos

jimlux writes:

Here's the application:
100 (or 1000) independent nodes (in space, as it happens) - I want to
calculate the probability that two nodes are within some delta f of
each other.

Provided I get correctly what you are trying to do: perhaps it would be
easier to take one of the programmable MEMS oscillators (and get a
programmer or find someone who can do that for you) and just trim each
of them the way you want it to.

Regards,
Achim.

+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Factory and User Sound Singles for Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Hi I think the gotcha there is the need for “very good phase noise”. Bob From: Achim Gratz Sent: Thursday, March 14, 2019 5:05 PM To: time-nuts@lists.febo.com Subject: Re: [time-nuts] statistical distribution of initial frequency errorin tcxos jimlux writes: > Here's the application: > 100 (or 1000) independent nodes (in space, as it happens) - I want to > calculate the probability that two nodes are within some delta f of > each other. Provided I get correctly what you are trying to do: perhaps it would be easier to take one of the programmable MEMS oscillators (and get a programmer or find someone who can do that for you) and just trim each of them the way you want it to. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ Factory and User Sound Singles for Waldorf Blofeld: http://Synth.Stromeko.net/Downloads.html#WaldorfSounds _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
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