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SRG-4500 User Guide (v7.0) Front Panel Menu System • 71
rate is unpredictable in the long term, it is not possible to predict the need for them more than six months in
advance. Leap Seconds have been added since 1972:
Semi automated support for Leap Seconds is built-in until 2034.
The operator programs in a UTC date and UTC time at which the Leap Second event is required. On this date, at
this time, a Leap Second is automatically added. International convention is that Leap Seconds are added, so the
time sequence is:
• 23: 59: 59 UTC
• 23: 59: 60 UTC
• 00: 00: 00 UTC
• 00: 00: 01 UTC
In a television station, 00:00:00 UTC might be in the middle of your busy schedule. If this is so, you can choose
another UTC time at which to action the Leap Second; for instance at
02:00:00 UTC the following morning. Only the date and hour at which the Leap Second
occurs is programmable. These dates are input as UTC so you may have to take account of your time zone and
daylight saving status.
Once the Leap Second event occurs, all the subsequent timecodes are recalculated so that they will also have moved
by one second. Subsequent Leap Seconds can be added by the operator as they are announced.
Table 7.9 Leap Seconds
Year June 30 December 31 Year June 30 December 31 Year June 30 December 31
1971 -- -- 1986 0 0 2001 0 0
1972 +1 +1 1987 0 +1 2002 0 0
1973 0 +1 1988 0 0 2003 0 0
1974 0 +1 1989 0 +1 2004 0 0
1975 0 +1 1990 0 +1 2005 0 +1
1976 0 +1 1991 0 0 2006 0 0
1977 0 +1 1992 +1 0 2007 0 0
1978 0 +1 1993 +1 0 2008 0 +1
1979 0 +1 1994 +1 0 2009 0 0
1980 0 0 1995 0 +1 2010 0 0
1981 +1 0 1996 0 0 2011 0 0
1982 +1 0 1997 +1 0 2012 +1 0
1983 +1 0 1998 0 +1 2013 0
1984 0 0 1999 0 0 2014 0
1985 +1 0 2000 0 0 2015