Resolution 8 of the 21st CGPM

Operational primary frequency standards

The 21st Conférence Générale des Poids et Mesures,


  • the importance of maintaining an adequate number of primary frequency standards to assure the accuracy and long-term stability of TAI,
  • that new primary standards are being developed using new technology,
  • that these new standards are significantly more accurate than the traditional primary standards upon which TAI and UTC have been based in the past,
  • that in consequence, the accuracy of TAI and UTC will rapidly become dependent on these new standards,
  • that considerable resources are required to maintain primary frequency standards as operational facilities to assure the accuracy of TAI,

requests national metrology institutes and other laboratories developing new primary standards, to make every effort to provide the human and other resources necessary to maintain as operational facilities these new standards upon which the accuracy of TAI and UTC will be based.

reference The reader should note that the official version of this Resolution is the French text

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