Digital phase-locked loop with automatic calibration function and automatic calibration method thereof

Abstract

A digital phase-locked loop with an automatic calibration function and an automatic calibration method thereof are provided. The digital phase-locked loop includes a frequency and phase detector, a calibration circuit, a frequency and phase locked circuit, and an oscillator circuit. The frequency and phase locked circuit outputs an initial control signal. The calibration circuit calibrates an initial frequency and outputs an initial calibration signal having a calibrated initial frequency when determining that the initial frequency does not fall within an allowable error calibration range. Thefrequency and phase locked circuit locks the calibrated initial frequency when determining that the calibrated initial frequency falls within a locked frequency range. The oscillator circuit outputsan oscillator signal according to the initial calibration signal and the initial control signal. Therefore, a resolution of the oscillator circuit can be improved by the automatic calibration of frequency drift caused by processes and environments.

Description

technical field [0001] The present invention relates to a digital phase-locked loop, and in particular to a digital phase-locked loop with automatic correction function and its automatic correction method. Background technique [0002] With the advancement of electronic technology, electronic products have become an indispensable tool in people's life. For example, communication products used for information exchange, information exchange with the outside world through communication products is already a daily work that people need to perform in their lives. In electronic communication products, the most common is the phase-locked loop device. However, in the PLL system, the frequency of the oscillator will drift due to factors such as the process and the temperature in the environment. Because the traditional phase-locked loop does not have the automatic correction function and cannot correct itself, in order to solve the problem of frequency drift, it is necessary to per...

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Problems solved by technology

However, in a PLL system, the frequency of the oscillator will drift due to factors such as the process and the temperature in the environment

Because the traditional phase-locked loop does not have the automatic correction function and cannot correct itself, in order to solve the problem of frequency drift, it is necessary to perform frequency correction through an additional machine, set the frequency domain range based on the consideration of process drift, and even increase the resolution if necessary , it is necessary to increase the number of control bits, resulting in higher cost, inconvenient use, and poor calibration efficiency

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