Self-adaptive rapid crystal locking method based on Clean-up digital phase-locked loop

Abstract

The invention discloses a self-adaptive rapid crystal locking method based on a Clean-up digital phase-locked loop. The method mainly solves the problems that an existing phase-locked loop is complex in circuit and can not meet a higher application requirement. The method is based on the phase-locked principle of the Clean-up digital phase-locked loop, firstly, the phase difference between a reference signal and a tested signal is worked out through frequency-inspected and phase-inspected calculation, the phase lock adaptively changes in the phase difference processing process of the software, the frequency difference and the phase difference are adjusted at the same time through a software algorithm, and then a high-precision analog-digital converter is controlled to output voltage controlled voltage to control crystal oscillation. The method is simple and can rapidly lock the phase, and meanwhile when the reference signal is affected by interference, the software can adjust coefficients in a self-adaptive mode, and smooth transition of output is achieved. The software processing mode is simple and effective, and the locking time is greatly shortened.

Description

Technical field [0001] The invention relates to a method for self-adaptively and quickly locking a crystal oscillator based on a Clean-up digital phase-locked loop, and belongs to a phase-locking technology in the field of time-frequency synchronization. Background technique [0002] The phase-locked loop is a feedback control system that uses an external reference signal to control the frequency and phase of the internal oscillation signal of the loop. By detecting the phase difference between the input signal and the output signal, it can reduce the phase noise of the input signal and synchronize the input and output signals. Purpose, the core of high-precision time-frequency equipment is a standard frequency signal with high accuracy and high stability, which is mainly generated by rubidium atomic clock and constant temperature quartz crystal; however, the short stability of rubidium atomic clock has obvious frequency drift characteristics. The GPS system has excellent long-te...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a method based on Clean-up digital phase-locked loop self-adaptive fast locking crystal oscillator, frequency locking and phase locking are carried out at the same time, fast locking of crystal oscillator is achieved through software algorithm self-adaptation, mainly to solve the complicated circuit of existing phase-locked loop , and cannot meet the high application requirements

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