| 摘要 |
PROBLEM TO BE SOLVED: To obtain superior frequency temperature characteristics by constituting the crystal vibrator by forming two inter digital electrodes on one surface of a crystal piece and forming a common electrode on the other surface. SOLUTION: On one surface of the AT-cut crystal piece 1, the inter-digital electrodes 2 and 2' are formed to constitute a series resonance circuit and on the other surface, the common electrode 3 is formed. At this time, the frequency deviationΔf of an oscillation frequency from a series resonance resonance frequency (f) is found fromΔf/f=1/2r1 (1+CL/C01 )+1/2r<2> (1+Cv/C02 ). Here, r1 and r2 are capacitance ratios viewed from T1 -T2 and T3 -T2 , CL and CV are load capacities, C01 and C02 are the electrode capacitances between the T1 and T2 , and T3 and T2 . Therefore, this interdigital two-electrode crystal vibrator has its oscillation frequency shifted b CV for a temperature compensation crystal oscillator to perform temperature compensation with CL, thereby making the frequency temperature characteristics constant irrelevantly to the frequency shift.
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