[time-nuts] DCF77 Analyzer/Clock
phk at phk.freebsd.dk
Thu Mar 23 04:18:29 EDT 2017
In message <20170323041013.GA4678 at panix.com>, Ron Bean writes:
He/They are missing out on a very big S/N improvement for DCF and
In reality only a very small subset of possible 2**59 timegrams are
potentially valid. For instance day of month cannot be > 31.
Even fewer timegrams can follow each other, for instance the day of
month cannot change unless a lot of other fields also change,
or conversely, a lot of fields can only change if the hour
field changes to one specicfic value.
I used this in my old NTPNS dcf77 decode, with the result that it
can lock on to DCF77 in a matter of minutes, even when most of the
pulses are mangled.
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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