[time-nuts] Thought experiment on a low cost timing board

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Feb 25 14:11:15 EST 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.


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Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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