| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique, for a crystal oscillation device equipped with what is called a thermostat bath, which can report with high accuracy a point of time when the internal temperature of the crystal oscillation device has stabilized after being powered on.SOLUTION: Determination of whether the temperature of an atmosphere in which a crystal vibrator 21 is placed has stabilized or not is made on the basis of an event that the value of a current flowing in the collector of a transistor 33 of a heater circuit unit 3 has dropped to or below a set value after the power to the oscillation device was turned on, as well as of the result of monitoring of a change in the moving average value of a current value supplied to the heater circuit unit 3. This determination is to determine whether a finite difference &Dgr;i between a moving average of 10 samples of a current detection value in, for example, the n'th sampling and a moving average of 10 samples of a current detection value in the n+1'th sampling is smaller than a threshold or not. |
