Quartz crystal resonator g sensitivity measurement methods and recent results

Area of Science:

• Electrical Engineering
• Materials Science
• Physics

Background:

• Quartz crystal resonators are critical frequency-determining components in electronic circuits.
• Vibration sensitivity is a key performance parameter, especially in harsh environments.
• Existing measurement techniques can be susceptible to errors from external factors like cable motion.

Purpose of the Study:

• To present an accurate technique for measuring quartz crystal resonator vibration sensitivity.
• To develop a method for identifying and mitigating measurement errors caused by coaxial cable vibration.
• To compare the vibration sensitivity of AT-cut and SC-cut quartz crystal resonators.

Main Methods:

• Utilizing a crystal oscillator circuit with a specific length of coaxial cable connecting the resonator to the sustaining stage.
• Implementing a method to determine and remove measurement errors introduced by cable vibration.
• Employing a passive phase bridge with a synthesized signal generator for alternative measurements.

Main Results:

• Test results for 40 and 50 MHz, fifth overtone AT-cut, and third overtone SC-cut crystals are reported.
• SC-cut resonators exhibited acceleration sensitivity (gamma vector) values typically four times smaller than AT-cut resonators (5x10^-10 per g).
• AT-cut resonators demonstrated smaller unit-to-unit gamma vector magnitude variation.
• Oscillator sustaining stage vibration sensitivity was characterized by an equivalent open-loop phase modulation of 10^-6 rad/g.

Conclusions:

• The described technique provides accurate measurements of quartz crystal resonator vibration sensitivity.
• SC-cut crystals offer superior acceleration sensitivity, while AT-cut crystals provide greater consistency.
• The method effectively addresses and corrects for errors associated with cable vibration in measurement setups.