CPT原子钟微波信号的设计和分析

根据被动型相干布居囚禁原子钟对微波信号的要求,利用小数分频锁相环技术实现了微波频率综合,并通过优化环路带宽得到最佳的输出相噪。测试结果表明:3 417 MHz微波输出在100 Hz处的相位噪声达到-80 dBc;中心频率±50 kHz范围内的杂散抑制达到54 dB,都接近于理论值。将产生的微波用于所研制的CPT原子钟,获得频率稳定度达到1 000 s内6×10-11-1/2,为目前国外商品钟水平。

The Design and Analysis of Microwave Signals for CPT Atomic Clock

In accordance with the requirement to microwave signal by the passive Coherent Population Trapping (CPT) atomic clock, microwave frequency synthesis is realized through fractional-N PLL technology, and best phase noise of the microwave is obtained by optimizing the loop width. Measurement results show that the achieved phase noise of the 3 417 MHz microwave is -80 dBc at 100 Hz and the spur suppression is 54 dB in±50 kHz scope, both are close to the theoretical values. The realized microwave is applied to our developed CPT atomic clock, and the short term frequency stability 6×10~(-11)τ~(-1/2)(1 s～1 000 s), which is the best frequency stability of present commercial CPT atomic clock，is obtained.