| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystal oscillator capable of displaying the numerical values of first to fifth temperature coefficients without increasing a displaying area. SOLUTION: By using the presence of strong correlation between a third order temperature coefficient and a fifth order temperature coefficient and between a second order temperature coefficient and a fourth order temperature coefficient when approximating the temperature variation characteristic of the resonance frequency of an AT cut crystal oscillator by a fifth order expression with respect to the ambient temperature, only first to third order temperature characteristics are displayed by laser marking on a package surface to obtain the residual fourth and fifth order temperature coefficients, thereby a space for displaying marking is economized.
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