[time-nuts] WWV Clock
Mike Monett
xde-l2g3 at myamail.com
Mon Nov 2 10:10:55 UTC 2009
Replying to my own post, there are two bits that indicate daylight
saving time changes. Here's a paragraph from page 27, Lombardi,
"NIST Time and Frequency Services", NIST Special Publication 432,
2002 Edition:
"Daylight saving time (DST) and standard time (ST) information is
transmitted at seconds 57 and 58. When ST is in effect, bits 57 and
58 are set to 0. When DST is in effect, bits 57 and 58 are set to
1."
"On the day of a change from ST to DST bit 57 changes from 0 to 1 at
0000 UTC, and bit 58 changes from 0 to 1 exactly 24 hours later. On
the day of a change from DST back to ST bit 57 changes from 1 to 0
at 0000 UTC, and bit 58 changes from 1 to 0 exactly 24 hours later."
<http://tf.nist.gov/timefreq/general/pdf/1383.pdf>
So it seems the HTAWI receives the bits correctly, but it does not
act on them until both are the same.
Some relevant articles are available:
NIST Special Publication 432, 2002 Edition
NIST Special Publication 250-67
WWVB RCC Recommended Practices 2009
<http://tf.nist.gov/stations/hflibrary.htm>
Regards,
Mike Monett
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