Title :
Quartz crystal resonator g sensitivity measurement methods and recent results
Author_Institution :
Westinghouse Electr. Corp., Baltimore, MD, USA
Abstract :
A technique for accurate measurements of quartz crystal resonator vibration sensitivity is described. The technique utilizes a crystal oscillator circuit in which a prescribed length of coaxial cable is used to connect the resonator to the oscillator sustaining stage. A method is provided for determination and removal of measurement errors normally introduced as a result of cable vibration. In addition to oscillator-type measurements, it is also possible to perform similar vibration sensitivity measurements using a synthesized signal generator with the resonator installed in a passive phase bridge. Test results are reported for 40 and 50 MHz, fifth overtone AT-cut, and third overtone SC-cut crystals. Acceleration sensitivity (gamma vector) values for the SC-cut resonators were typically four times smaller (5*10/sup -10/ per g) than for the AT-cut units. However, smaller unit-to-unit gamma vector magnitude variation was exhibited by the AT-cut resonators. Oscillator sustaining stage vibration sensitivity was characterized by an equivalent open-loop phase modulation of 10/sup -6/ rad/g.<>
Keywords :
acceleration measurement; crystal resonators; oscillators; quartz; vibration measurement; 40 MHz; 50 MHz; SiO/sub 2/; acceleration sensitivity; cable vibration; coaxial cable; crystal oscillator circuit; equivalent open-loop phase modulation; fifth overtone AT-cut crystals; g sensitivity measurement; measurement errors; oscillator sustaining stage; oscillator-type measurements; passive phase bridge; quartz crystal resonator; synthesized signal generator; third overtone SC-cut crystals; unit-to-unit gamma vector magnitude variation; Bridge circuits; Coaxial cables; Measurement errors; Oscillators; Performance evaluation; Phase measurement; Signal generators; Signal synthesis; Testing; Vibration measurement;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on