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

[Poul-Henning Kamp]

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.