Redefinition of unit of time and research progress of primary frequency standard in NIM

doi:10.12267/j.issn.2096-5931.2022.07.001

Abstract

Abstract:

The redefinition of the International System of Units makes the definitions of other base units directly or indirectly related to the unit of time (second) except that of the amount of substance. High-accuracy time and frequency standards plays an important role in national economy, national defense and scientific research. This paper mainly introduces the development of the definition of the second from astronomical second to atomic second, and the discussion on the redefinition of the second and the requirements for atomic clocks. Finally, it introduces the research work and counter measures of National Metrology Institute of China on time and frequency standards.

Key words: definition of the unit of time, time and frequency primary standard, caesium fountain clock, optical clock

CLC Number:

TN99
O562.3

CAO Shiying, FANG Fang. Redefinition of unit of time and research progress of primary frequency standard in NIM[J]. Information and Communications Technology and Policy, 2022, 48(7): 2-8.

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URL:

http://ictp.caict.ac.cn/EN/10.12267/j.issn.2096-5931.2022.07.001

http://ictp.caict.ac.cn/EN/Y2022/V48/I7/2

Figures/Tables 7

References 22

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