Design Of ?R Digital Filter Based On All-digital Phase-locked Loop

With the rapid development of digital communication technology,the research on digital signal processing has attracted wide attention.Because digital signal has the advantages of simple coding,strong anti-interference and large amount of information,digital signal processing gradually replaces analog signal processing in many aspects,which makes more and more people deeply study digital communication technology.It is precisely because of the rapid development of digital communication technology that the full digitization of PLL in the field of radio frequency communication has been paid much attention.In the design of all-digital phase-locked loop,it is very important to use digital filter instead of traditional analog loop filter.Firstly,the design principle of PLL is introduced in detail,then the system structure of all digital PLL is analyzed,and the difference between all digital PLL and analog PLL is compared.Then the design principle and structure of IIR(Infinite Impulse Response)digital filter are introduced in detail.Firstly,a new all digital phase-locked loop(PLL)structure is proposed and the structure of IIR digital filter is determined.Then the algorithm level of IIR filter is verified by MATLAB software.Simulink is used to simulate the waveform to verify the correctness of the filter design.Secondly,an improved direct type II digital filter structure is proposed in the design process.Compared with the previous structure,the improved structure has greatly improved its operation speed.The improved structure has been verified and tested,which proves that the design is correct and the improved structure has indeed accelerated the operation speed.After testing,the IIR digital filter is imported into the layout design software Encounter to obtain the layout file of the digital filter.Finally,the layout file is simulated and tested.The simulation results show that the IIR digital filter designed in this paper meets the expected requirements and meets the design rules.In this paper,the design principle of all-digital phase-locked loop and the design structure of IIR digital filter are studied,and an improved IIR digital filter structure is proposed based on it.The structure is simulated and tested,the layout design of IIR digital filter is completed.And verify the reliability of IIR digital filter during the processof the simulation through the post-simulation of the layout.