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Dissemination of Time

Working Group 4.42


In PTB’s wide spectrum of tasks, dissemination of legal time is one of the most important service tasks performed for the public. Whereas atomic clocks a priori furnish only time intervals of extremely precise duration, the realization and the dissemination of legal time require a comparison and combination of the signals of the different PTB clocks. Moreover, the second marks must be brought into a well-defined relation to the international time system. This purpose serve international time and frequency comparisons via GPS and telecommunication satellites. The finally obtained national reference time scale UTC(PTB) forms the basis of legal time which is thus realized in a cooperation between PTB working groups “Time Standards” (4.41) and “Transmission of Time” (4.42).


Geneva, 19 November 2015 – The ITU World Radiocommunication Conference (WRC-15), currently in session in Geneva from 2 to 27 November, has decided that further studies are required before a decision on a future reference time-scale can be made. There had been expectations by many that already now the modification of coordinated universal time (UTC) and suppressing the so-called “leap second” would be made

The current decision calls for a report to be considered by the World Radiocommunication Conference in 2023. Until then, the realization of UTC shall continue to be made as up to now. Further leap seconds as the one in summer 2015 will thus come for sure.

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