Digital temperature-compensating crystal oscillator, and method for stabilizing frequency thereof

A frequency stabilizing method in a digital temperature compensating oscillator, comprising the steps of:

• initializing variables such as a temperature data accumulation arithmetic variable, a loop counting variable, an error counting variable, and a variable for counting occurrence times of a temperature data same as a temperature code;
• obtaining a temperature data by using a temperature sensing means and an analog/digital converting means;
• checking as to whether the temperature data thus obtained is a first temperature data;
• checking as to whether the temperature data thus obtained comes within a predetermined range, if it is not the first temperature data;
• accumulating the temperature data, incrementing a loop counter by 1, and repeating from the step of obtaining the temperature data until said loop counter shows a predetermined value, if the temperature data thus obtained comes within the predetermined range;
• incrementing an error counter by 1, and repeating from the step of obtaining the temperature data, if the temperature data thus obtained departs from the predetermined range;
• adopting the present temperature data as the temperature code if the temperature data is the first temperature data or if said error counter shows a value more than a predetermined value;
• adopting an average value as the temperature code by dividing an accumulation variable by a number of accumulations if a loop counter value is more than a predetermined value;
• and
• carrying out a temperature compensation with the temperature code thus adopted, and then, repeating from the variable initializing step until oscillations are terminated.

A digital temperature compensating oscillator comprising:

• a temperature sensing means for sensing an ambient temperature;
• and
• an analog/digital converting means for converting sensed values into digital signals, so as to correct frequency variations in accordance with variations of the ambient temperature,
• the digital temperature compensating oscillator further comprising:
• a frequency stabilizing section for checking as to whether a digital data representing the ambient temperature comes within a predetermined temperature range, for accumulating the digital data coming within the predetermined temperature range by a predetermined number of times;
• and for outputting an average value of the digital data thus accumulated or the digital data departing from the predetermined temperature range as a temperature code.