Analysis of frequency stability of atomic clock under sinusoidal vibration
Cao Yu1, Lü Shanwei1, Feng Keming2, Dang Qun1*
1. School of Electronics and Information Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China;
2. School of Electronics and Information Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
Vibration effects on the atomic clock(atomic frequency standard) could be divided into three parts: atomic resonance effects, crystal oscillator effects and servo-loop effects. Within the vibration frequency, the phase noise of crystal oscillator under sinusoidal vibration was only related to acceleration sensitivity, peak acceleration and vibration frequency, and it has no concern with the phase noise in the static state. But above the vibration frequency, the phase noise of crystal oscillator was the same with the value in the static state. By the frequency stability transfer formulas from the atomic clock to crystal oscillator, vibration effects on crystal oscillator was combined with vibration effects on the atomic clock through servo loop. For computing Allan variance directly from integral equation of phase noise, the several analysis formulas were derived by residue theorem. With increased servo loop bandwidth, vibration effects on frequency stability of the atomic clock can be controlled effectively. Two other methods are analyzed to improve the performance of the atomic clock under vibration: reducing vibration frequency and choosing crystal oscillator with smaller acceleration sensitivity.