QUARTZ CRYSTAL RESONATOR-G SENSITIVITY MEASUREMENT METHODS AND RECENT RESULTS

A technique for accurate measurements of quartz crystal resonator vibration sensitivity. 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 oscillalor-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, 5th overtone AT-cut and third overtone SC-cul crystals. Acceleration sensitivity (gamma vector) values for the SC-cul resonators were typically four times smaller (5 × 10−10 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 10−6 rads per g. © 1990 IEEE