[time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Dec 16 10:56:32 EST 2006


In message <000001c72126$ecc89270$0202fea9 at athlon>, "Ulrich Bangert" writes:
>Poul,
>
>i appreciate your comments always a lot! But dynamical methods are
>especially usefull when the input parameters are subject of change,
>aren't they?

They are also very useful for amateur projects where the users do
not have the necessary measurement facilities and likely use random
components bought on ebay :-)

>But how would you solve the system of equations with TWO
>unknowns (LO and GPS jitter) if you have only ONE information?

The way you do this is by measuring the ADEV between your two sources
and how it changes with changes in your timeconstant.

In my experience, the better way is to start with a short timeconstant
and increase it, until the ADEV shows signs of detoriation.

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



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