Evaluation of nonlinear elastic coefficient causing frequency shifts in AT-cut resonators

The authors describe an experimental evaluation scheme of the fourth order nonlinear elastic constant of quartz C/sub 6666/ using AT-cut resonators. The evaluation has been made from measured quadratic frequency changes against excitation currents and actual vibration amplitude distributions of thickness-shear vibrations measured by an optical fiber vibration sensor. More reasonable estimates of C/sub 6666/ were obtained compared with those previously reported which vary considerably from each other.<
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