QIN Lei，GAO Wei，CHEN Zhi-yong，SHENG Rong-wu

(Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China)

Abstract: The impact of the radio frequency(RF) multiplier on the rubidium vapor cell frequency standard(RFS) is discussed. A novel digital phase-locked loop(PLL) multiplier designed for miniature RFS is introduced. The stability of the RFS system, in which the digital PPL multiplier is adopted, is less than(at least, equal to) 3×10-11 (σ y (τ =1 s) ),coming up to the performance level of the miniature commercial RFS, whereas the size of the circuit board of the multiplier is half that of the original one and the power consumption is 1/3 that of the original circuit.

Key words: rubidium vapor cell frequency standard; PLL multiplier; phase noise