[time-nuts] Thought experiment on a low cost timing board
Poul-Henning Kamp
phk at phk.freebsd.dk
Sat Feb 25 19:11:15 UTC 2006
In message <20060225.120955.29271924.cfmd at bredband.net>, Magnus Danielson writes:
>> Consider adding a D/A converter for tweaking OCXO. Using the two-tier
>> trick which SRS uses in the PRS10 may be a good and cheap way.
>
>two-tier trick? Lacking the PRS10 schematics/service manuals...
They have two 12 bit D/As which are summed through a 1:1000 network
to give around 20 bits of effective resolution at the cost of some
discontinuities.
Because the ratio is only a quarter of the full ratio of the individual
D/A's, they can always center the interresting range in the lower D/A's
range.
--
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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