关键词: 频率标准, 晶振, 原子频率标准, 日频率稳定度, 日频率漂移率

Abstract: Time and frequency are critical elements for national economy,scientific research and national safety.They will be introduced,the development and characteristics of ultra stable crystal oscillator,rubidium atomic frequency standard,active hydrogen atomic frequency standard,cesium atomic frequency standard,coherent population trapping atomic clock,cryogenic sapphire oscillator,ultra stable optical-cavity-based microwave source and cesium atomic fountain clock,in the thesis.Domestic rubidium atomic frequency standard was loaded in Beidou satellite,and has been broken into foreign monopoly.Active hydrogen atomic frequency standard and cesium atomic frequency standard have been applied in various fields.However daily frequency stability and Daily frequency drift rate need be improved on and on.Cesium atomic fountain clock has reached international advanced level.New type of atomic frequency standards are growing rapidly.

Key words: Frequency standard, Crystal oscillator, Atomic frequency standard, Daily frequency Stability, Daily frequency drift rate