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Discussion of precise time and frequency measurement

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Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

HM
Hal Murray
Mon, Aug 1, 2016 5:35 PM

If I start with a serial string that is good to 10ms and my goal is 10 ppb,
I’m waiting for a  million seconds per sample.

That also assumes that the temperature isn't changing while you are
collecting the data.

--
These are my opinions.  I hate spam.

kb8tq@n1k.org said: > If I start with a serial string that is good to 10ms and my goal is 10 ppb, > I’m waiting for a million seconds per sample. That also assumes that the temperature isn't changing while you are collecting the data. -- These are my opinions. I hate spam.
BC
Bob Camp
Mon, Aug 1, 2016 6:45 PM

HI

You very much are not done when you get your point at a million seconds. That’s
just where you get to start ….

Since you are talking about nearly two weeks per sample, there are a lot of things
that could happen. If your loop needs ten samples to do much with, it will be 4 months
before anything at all happens. In that period, you need to wonder if the power will stay on
for the whole time …. (thunderstorms in the area at the moment …)

Even if you back off to “I only need 1 ppm”, you still have a really slow process.

Bob

On Aug 1, 2016, at 1:35 PM, Hal Murray hmurray@megapathdsl.net wrote:

kb8tq@n1k.org said:

If I start with a serial string that is good to 10ms and my goal is 10 ppb,
I’m waiting for a  million seconds per sample.

That also assumes that the temperature isn't changing while you are
collecting the data.

--
These are my opinions.  I hate spam.


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HI You very much are not *done* when you get your point at a million seconds. That’s just where you get to *start* …. Since you are talking about nearly two weeks per sample, there are a *lot* of things that could happen. If your loop needs ten samples to do much with, it will be 4 months before anything at all happens. In that period, you need to wonder if the power will stay on for the whole time …. (thunderstorms in the area at the moment …) Even if you back off to “I only need 1 ppm”, you still have a really slow process. Bob > On Aug 1, 2016, at 1:35 PM, Hal Murray <hmurray@megapathdsl.net> wrote: > > > kb8tq@n1k.org said: >> If I start with a serial string that is good to 10ms and my goal is 10 ppb, >> I’m waiting for a million seconds per sample. > > That also assumes that the temperature isn't changing while you are > collecting the data. > > > > -- > These are my opinions. 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.