Abstract: Coherent Population Trapping (CPT) atomic clock is a new type of atomic clock with low-power, small volume and excellent stability. In this paper, to optimize the digital filtering algorithm of miniature CPT atomic clock, we use Cascade Integrator Comb (CIC) filter as the front filter and low order FIR filter as the end filter. In the case of the same noise suppression radio, new filtering module has saved logic resources and reduced power consumption. Based on the above design, the filtering module reaches the filtering effect of 55dB and saves about 42% of FPGA logic resources.

Key words: CPT atomic clock, Digital filter, CIC filter, FIR filter