Improving the frequency stability of atomic frequency standard basing on the noise asynchromism correction

We propose an improvement for increasing the performance of locked periodic atomic frequency standards(AFS), based on correcting the noise of the asynchronism of phase-detecting and feedback process. Theoretical analysis and numerical simulation show that the method can optimize the stability AFS which is related with d. And is the duty of phase-discriminating of AFS. If in-loop noise possesses white frequency noise characteristics, the stability will decrease following the coefficient of √(1 − d). Specially, when d approaches to 1, the stability will reach the limit of quantum project noise. Here we demonstrate three schemes to realize the idea in experiments and overlap-feedback is the most easily implemented one. Considering Dick effect in our method, the stability of our atomic fountain will be better than 1 × 10
^{−14τ−1/2}
at d>0.93.