| 摘要 |
PURPOSE:To make output signals be time standard by changing the frequency dividing ratios of a frequency divider according to the differences in frequencies of two oscillation circuits. CONSTITUTION:Piezoelectric vibrators 3, 4 are connected to oscillation circuits 5, 6 respectively and the frequency-temperature characteristics of an oscillation frequency f1 in the oscillation circuit 5 are shown in the curve 10. The frequency- temperature characteristics of an oscillation frequency f2 in the oscillation circuit 6 are shown in the curve 11. The operation of DELTAf=f2-f1 is performed in a subtractor 7. Next, K x (DELTAf)<2> is created by an arithmetic circuit 8. Further, in a frequency dividing circuit 9, the frequency dividing ratio is changed according to the magnitude of the signal having been created in the arithmetic circuit 8 at the time of obtaining the output signal of a desired period by dividing down f1, whereby the output signal in which the frequency-temperature characteristics of the piezoelectric elements are as flat as like the curve 14 is obtained. |
