| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystal oscillator (OCXO), generating a temperature detection value on the basis of a signal corresponding to difference between oscillatory frequencies of a first and a second crystal oscillators, capable of optimizing the scale of a circuit for performing temperature control.SOLUTION: If oscillation outputs of a first and a second crystal oscillators 10, 20 are taken as f1, f2 and oscillatory frequencies of the oscillation outputs at reference temperature are taken as f1r, f2r respectively, a frequency difference detection section 3 arithmetically processes {(f2-f1)/f1}-{(f2r-f1r)/f1r} to obtain a digital value. At the subsequent stage of the arithmetically processed part, there are provided an accumulation section that accumulates the digital value each time a clock input is made and a rounding process 75 that rounds an accumulated digital value. The accumulation number and the rounding amount can be mutually set independently. |
