[ntp:questions] Re: ntp servers reporting leap second erroneously?

David L. Mills mills at udel.edu
Sun Oct 23 13:34:21 UTC 2005


There is no provision in the NIST WWV/H/B timecode for a leap deletion 
nor is ther provision in the hardware timecode generators for that. The 
DUT1 is a signed adjustment to the current UTC to produce UTC1. The 
adjustment changes sign after a leap second to reflect the current 
offset of UTC1 from UTC. The DUT1 sign has nothing to do with the 
insertion/deletion of the leap.


Tom Van Baak wrote:
>>The DUT1 does take on negative and positive values as the TAI offset
>>wanders; however, the broadcast timecodes of WWV/H and WWVB have only
>>four bits, one of them the sign. There is no provision for a delete
>>second. So, if the UT1 moves north instead of south, more than 0.7 s
>>would be lost.
> Dave, I think we've been through this before. The NIST
> radio timecode can handle either insertion or deletion
> of leap seconds. The LS bit tells you if a leap second
> is pending; the sign of DUT1 bit(s) tell you if the leap
> is positive (inserted) or negative (deleted). So there is
> provision; there is no problem.
> /tvb
> http://www.leapsecond.com/notes/leap-watch.htm

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