Analysis of two-stage passive vibration isolation system for crystal oscillator at high-frequency vibration

In this paper, the influence of vibrations on the crystal oscillator is analyzed in theory and the function of SSB phase noise under vibrations is given. To restrain high-frequency vibration effectively, a two-stage passive vibration isolation system for crystal oscillator is presented. This kind of vibration isolation system has low displacement transmissibility at high-frequency vibrations. The simulations and experiments are carried out. Experimental results show that at the random vibration whose acceleration spectral density is 0.05 g²/Hz with frequency range 20 Hz to 2000 Hz, the SSB phase noise level of a 12.8 MHz AT-cut crystal oscillator (whose acceleration sensitivity is about 2times10^-9 /g ) is reduced approximately from -100 dBc/Hz to -120 dBc/Hz at 1 KHz offset by this vibration isolation system.