Phase-locked loop phase difference adjustment device

Abstract

The invention provides a phase-locked loop phase difference adjusting device which comprises a phase difference detection module, a data processing module, and a digital-to-analog conversion module. A phase-locked loop inputting clock and a phase-locked loop output clock are connected to the input end of the phase difference detection module, and are used for detecting the phase difference of the input clock and the output clock; the data processing module is connected to the phase difference detection module, converts the detected phase difference data in proportion into DAC_data and outputs the DAC_data; the digital-to-analog conversion module is connected to the data processing module, takes the DAC_data as input data and converts the DAC_data as output currents, and the output currents are used as the input of a phase-locked loop filter. The phase-locked loop phase difference adjusting device is used in cooperation with an existing phase-locked loop, can adjust the phase between the input clock and the output clock dynamically under the situation that the losing lock phenomenon of the phase-locked loop does not occur, and improves synchronism.

Description

technical field [0001] The invention relates to signal processing technology in communication, in particular to a device for phase-difference adjustment of a phase-locked loop. Background technique [0002] PLLs are widely used in technical fields such as broadcast communication, frequency synthesis, automatic control and clock synchronization. It consists of phase detector, loop filter and voltage controlled oscillator. The phase detector is used to identify the phase difference between the input signal Ui and the output signal Uo, and output the error voltage Ud. The noise and interference components in Ud are filtered out by a low-pass loop filter to form the control voltage Uc of the voltage-controlled oscillator (VCO). The result of Uc acting on the voltage-controlled oscillator is to make the phase difference between the output clock and the input clock of the phase-locked loop constant, so that the loop is locked, which is called lock-in. In a common phase-locked l...

AI Technical Summary

Problems solved by technology

Under the current technology, the phase difference between the input and output of ordinary phase-locked loops is relatively large, which is far from meeting the phase difference requirements in practical applications.

In addition, the current common phase-locked loop will only start the phase adjustment when the lock is lost, and cannot be adjusted dynamically if the lock is not lost. For many products using the phase-locked loop, the loss of lock will affect the normal operation of the product. work is not acceptable

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