Crystal oscillator system, crystal oscillator frequency calibration device and method

Abstract

The invention discloses a crystal oscillator system, a crystal oscillator frequency calibration device and method. The crystal oscillator system with a frequency self-calibration function comprises a crystal oscillator, a crystal oscillator driving module, an external capacitor, a control module, a capacitor matching module and a load capacitor measurement module; one end of the external capacitor is connected with the crystal oscillator, and the other end is grounded; the capacitor matching module is connected with the external capacitor and used for providing a parallel capacitor for the external capacitor; the external capacitor and the parallel capacitor form a load capacitor together; the load capacitor measurement module measures the load capacitor, and sends a load capacitor measurement result to the control module; the control module is connected with the capacitor matching module, and used for adjusting a parallel capacitor numerical value output by the capacitor matching module according to the load capacitor measurement result, thereby enabling the load capacitor to be equal to the given target value. The oscillation frequency of the crystal oscillator is once calibrated by using the crystal oscillator system disclosed by the invention.

Description

technical field [0001] The invention relates to the technical field of crystal oscillators, in particular to a crystal oscillator system, a crystal oscillator frequency calibration device and a method. Background technique [0002] The clock signal is a signal with a fixed frequency, which is the basis of sequential logic and can determine when the state in the logic unit is updated. Therefore, digital signals must be controlled by the clock signal to perform accurate operations. Generally, the clock signal is generated by an oscillator. Oscillators can be divided into resistance-capacitance oscillators, inductor-capacitor oscillators, crystal oscillators, etc. according to the circuit structure. Crystal oscillators are widely used in technical fields such as communication networks, wireless data transmission, and high-speed digital data transmission because of their high-precision and high-stability performance. [0003] In order to obtain a fixed frequency clock signal, ...

AI Technical Summary

Problems solved by technology

Existing crystal oscillators often use two methods for frequency calibration: (1) directly measure the frequency of the crystal oscillator, and then use the frequency calibration module to adjust the frequency of the crystal oscillator. This method requires high precision of the frequency calibration module, and The structure of the frequency calibration module is very complicated; (2) Measure the frequency of the crystal oscillator, adjust the internal capacitance, resistance and other devices of the crystal oscillator until the output frequency of the crystal oscillator reaches the target value. This method often requires multiple adjustments to make the crystal The output frequency of the crystal oscillator reaches the target value and cannot be adjusted in place at one time

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