A Method of Adjusting Frequency Temperature Coefficients and Resonant Frequency for NS-GT Cut Quartz Crystal Resonators

Abstract

This paper describes a method of adjusting the frequency-temperature coefficients and resonant frequency of NS-GT cut quartz crystal resonators. It is well known that NS-GT cut resonators show good frequency-temperature behavior because the first-, second- and third-order temperature coefficients α+, β+, γ+ for principal vibration can be approximately zero. However, a distribution of frequency-temperature behavior takes place in production. In order to obtain resonators with better and stable frequency-temperature behavior within +/-2.5 ppm over a temperature range of -30 to +85° C in production, an absolute value of α+ must be less than 5×10-8/° C. The adjustment method described makes it possible to control α+ easily. The NS-GT cut resonators' frequency-temperature characteristics were found to be mostly within +/-1.0 ppm in the above-mentioned temperature range.