Research And Design Of All-digital Phase-locked Loop With Pipelined Circuit Structure

Phase-locked loop circuit is an important module in electronic system.It is essentially a closed-loop feedback control system.By comparing the phase difference between the input signal and the output feedback signal,the output frequency of the oscillator is controlled,and the phase locking of the phase-locked loop is finally made.Compared with analog phase-locked loop,all-digital phase-locked loop has the characteristics of high integration,strong anti-jamming performance and good portability.However,there are still some problems in the existing all-digital phase-locked loop,such as slow phase locking speed,high power consumption,and the system design parameters can not be dynamically adjusted and so on.In order to solve these problems,an all-digital phase-locked loop with pipelined circuit structure is proposed in this paper.The phase-locked loop is mainly composed of digital phase discriminator,digital filter,numerical control oscillator,automatic variable mode circuit and automatic frequency measurement circuit constitute.The digital phase discriminator uses a dual-D trigger-type phase detector,the digital filter is composed of a reversible counter,and the numerical control oscillator is composed of a buckle pulse circuit and an N-frequency divider.The innovation of this design is to optimize the circuit structure of digital filter circuit,N frequency divider,automatic converter circuit and automatic frequency measuring circuit in all-digital phase-locked loop system by pipeline technology,which can improve the phase locked speed of the system and reduce the power consumption.The dynamic adjustment of the parameters of the phase-locked loop system with pipelined circuit structure is realized,and the performance of the phase-locked loop system is improved.The automatic mode-changing circuit can adjust the parameters of the digital filter automatically according to the change of phase error,and solve the contradiction between the phase-locked speed and the stability of the system.The automatic frequency measurement circuit can adjust the parameters of N frequency divider automatically according to the change of input frequency,which improves the frequency tracking speed of phase locked loop and expands the frequency locking range of phase locked loop.The PLL circuit adopts the top-down design method by using the very high speed integrated circuit hardware description language,the EP3C40Q240 C of Altera company is used to realize the hardware circuit,and the circuit is verified by system simulation and hardware experiment.The design software is used to analyze the power consumption and delay of the system.Compared with the traditional phase-locked loop,the all-digital phase-locked loop can accelerate the information processing speed,reduce the power consumption and expand the range of the phase-locked loop.Its phase-locked speed is fast,the fastest can be at 2?s Complete locking,locking range is 10Hz-100 MHz,and easy to integrate,more versatile.