Method for measurement of the sensitivity of crystal resonators to repetitive stimuli

This paper describes a simple method for the measurement of the effect of periodic stimuli on the frequency of crystal resonators. The technique has been implemented for the measurement of both acceleration and pressure sensitivity. The system is based around a passive method that has been previously used for residual phase noise measurement. In the case of acceleration sensitivity measurement, the crystal is placed on a vibration table. In this case a sinusoidal acceleration is applied to the crystal in each of three mutually orthogonal axes. To measure pressure sensitivity, a simple chamber has been built in which the barometric pressure is modulated around standard atmospheric conditions by about ±80 mbar. For typical high Q 10 MHz 3^rd overtone quartz resonators, the measurement resolution that has been achieved by the system is in the low parts in 10¹² per g or about 10^-9 per bar. The measurement method is relatively fast, and it obviates the need to stabilize precisely the temperature of the resonator.