The Physikalisch-Technische Bundesanstalt (PTB) is the national metrology institute of the Federal Republic of Germany, with scientific and technical service tasks.
To have a time basis for this, PTB operates several atomic clocks (currently two cesium clocks and, since 19, respectively, two cesium fountain clocks.) By order of PTB, the synchronization of clocks via radio is performed via the time signal transmitter DCF77 operated by Media Broadcast.
Computers which are connected with the Internet can obtain the time also via the three public NTP time servers of PTB.
The Units and Time Act Bundesgesetzblatt (Federal Law Gazette), volume 2008, part I, No. 1185 ff., 11 July 2008] assigns all tasks which are related with the realization and dissemination of the units to PTB.
All legally relevant aspects regarding the units as well as PTB’s responsibilities have been combined in this Act.
Together with NIST in the USA and the NPL in Great Britain, PTB ranks among the leading metrology institutes in the world.
As the National Metrology Institute of Germany, PTB is Germany's highest authority in terms of correct and reliable measurements.
As the basis for its tasks, PTB conducts fundamental research and development in the field of metrology in close cooperation with universities, other research institutions, and industry. 15 million euros were, in addition, canvassed as third-party funds for research projects.
The Units and Time Act entrusts PTB also especially with the dissemination of legal time in Germany.
PTB's tasks are as follows: the determination of fundamental and natural constants; the realization, maintenance and dissemination of the legal units of the SI; and safety technology.
This spectrum of tasks is supplemented by services such as the German Calibration Service (Deutscher Kalibrierdienst, DKD) and by metrology for the area regulated by law, metrology for industry, and metrology for technology transfer. 183 million euros at its disposal; in 2012, approx.
In Berlin-Adlershof, PTB operates the MLS (Metrology Light Source) electron storage ring for calibrations in the field from the infrared (THz) to the extreme ultraviolet (EUV).