Method and device for maintaining clock frequency

Abstract

The invention provides a clock frequency keeping method and device. The method comprises the steps of when a reference clock source is abnormal, obtaining current temperature information of a high-stability crystal oscillator and a current frequency control word of a clock IC; separating a current temperature signal and a current aging signal from the current frequency control word; carrying out temperature prediction according to the current temperature signal and the current temperature information; carrying out aging prediction according to the current aging signal; determining temperature compensation and aging compensation according to temperature prediction and aging prediction results; and determining the frequency control word written into the clock IC according to the temperature compensation and aging compensation, thereby keeping the output frequency of the clock IC unchanged. According to the method, on the premise of not generating high cost, when the reference clock source is abnormal, the output stability and accuracy of the clock frequency are kept.

Description

technical field [0001] The invention relates to the field of information processing, in particular to a clock frequency maintaining method and device. Background technique [0002] With the rapid development of mobile communication technology, the quality requirements of the clock are getting higher and higher. In the base station system, a high-stable crystal oscillator (OCXO or TCXO with temperature compensation) is usually used as the crystal clock. Once the crystal clock has a frequency error, it will cause the entire base station to fail. Therefore, it is necessary to ensure the stability and accuracy of the crystal oscillation frequency output. [0003] Temperature and time changes will change the crystal oscillation frequency and generate errors. Therefore, in the base station control system, a stable reference clock is usually used, and a set of phase-locked control technology is used to compensate the change of the crystal oscillation frequency and the error gener...

AI Technical Summary

Problems solved by technology

[0004] In the case of abnormal reference clock (reference error or loss), the crystal clock has no error compensation of the reference clock source and will be in a free oscillation state. The crystal clock will be affected by aging and ambient temperature. In the case of long-term reference clock abnormality, The crystal oscillation frequency will change, and finally the output frequency of the crystal clock will not meet the requirements of the base station system, resulting in the failure of the base station

[0005] For this reason, the current common solution is to use a high-stability (0.1ppb) crystal oscillator to solve the problem of inaccurate crystal clock frequency when the reference source is abnormal. Since this kind of crystal oscillator is expensive, this solution will bring high production costs.

[0006] In addition, the voltage control method can also be used to adjust the frequency output of the crystal oscillator. This solution will be limited by the frequency adjustment range of the crystal oscillator.

Due to the need to adjust the frequency of the crystal oscillator, once the frequency adjustment exceeds the frequency adjustment range allowed by the crystal oscillator, the problem of frequency adjustment exceeding the limit will occur, and the frequency calibration cannot be completed. At this time, the crystal oscillator can only be replaced.

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