The Mechanical Vibration Isolation Of The Crystal Oscillator

As the ultra stable standard frequency sources, crystal oscillators are widely used on different kinds of high-speed aircrafts. The electronic equipment on these high-speed aircrafts often has to work under a bad vibration environment. The crystal oscillator is very sensitive to vibrations. To provide the necessary spectral purity, a vibration isolation system for crystal oscillator is required to keep the accuracy and stability of electronic equipment.In this dissertation, the influence of vibrations on the crystal oscillators is analyzed based on the working principle of the crystal oscillators. The method of calculating SSB phase noise under different vibration environment is given. And to restrain the random vibration with frequency range 20Hz to 2000Hz effectively, several kinds of passive vibration isolation system models are analyzed, especially the displacement transmissibility of each model is calculated and simulated by Matlab. Furthermore, the standing wave effect of vibration isolators is also analyzed. Finally, a design of two-stage passive vibration isolation system for crystal oscillator is presented. This kind of vibration isolation system has low displacement transmissibility. The simulations and experiments are carried out.This dissertation introduced the instrument and procedure of experiment. Experimental results show that at the random vibration whose power spectral density is 0.05g2/Hz with frequency range 20Hz to 2000Hz, the dynamic SSB phase noise level of a 12.8MHz AT-cut crystal oscillator is reduced by this vibration isolation system effectively.