[time-nuts] An (unknown?) nasty feature of the DDS principle for time nuts applications
phk at phk.freebsd.dk
Tue Jan 25 14:03:00 UTC 2011
In message <E34BA9BA1D7340AD88EF19CDD971F3D8 at athlon>, "Ulrich Bangert" writes:
>However for very precise timing a DDS may simply be unsuited.
No, it just has to be correctly designed.
For integral Hz resolution output, you want to feed it a frequency
with us 2^N(*10^M) where N is equal to the width of the accumulator.
However, don't overlook the value of a small frequency offset, which,
if used correctly, can be used as a 'vernier' to discover minute
unlinearities in timing circuits.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
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