Time keeping method for controlling voltage-controlled crystal oscillator based on temperature variation difference

The invention provides a time keeping method for controlling a voltage-controlled crystal oscillator based on a temperature change difference, and the method comprises the steps: collecting the ambient temperature around the crystal oscillator when the crystal oscillator normally operates to track a reference source, and averaging the ambient temperature through accumulation to generate a temperature reference; subtracting the reference temperature from the ambient temperature around the crystal oscillator after the reference source is disconnected, and calculating the temperature deviation around the crystal oscillator; and converting the temperature deviation into the voltage-controlled voltage of the crystal oscillator, and eliminating the frequency deviation of the crystal oscillator at the holding moment. According to the invention, the crystal oscillator is controlled according to the relationship between the temperature deviation and the control quantity of the voltage-controlled crystal oscillator, so