Design And Implementation Of An X-band Low Phase Noise Multifunctional Frequency Source Based On PLL

With the rapid development of mobile communication systems,fifth-generation(5G)wireless communication is expected to be deployed in the early 2025 s.The frequency synthesizer is a key component in modern communication systems.It can generate excitation signals and be used as a local oscillator in various up-conversion and down-conversion schemes.Frequency synthesizers are currently widely used in many modern devices,such as radio receivers,televisions,mobile phones,wireless phones,walkie-talkies,radio communications,cable TV converters,satellite receivers and global positioning systems.The high-performance frequency synthesizer is an indispensable key link in modern communication systems.The research of frequency synthesizer has also received more and more scholars' research and attention.The research content of this paper is as follows:This article is the introduction.It mainly introduces the research background and significance of this topic,and briefly introduces the development history of frequency synthesizers.It shows that frequency source design is an indispensable part of modern communication,and it may happen in the future.Played a key role in the war.Then it introduces the latest situation of frequency source design at home and abroad in recent years and the published literature,and explains in detail the development trend of frequency synthesizer design and the changes in design process.This article introduces the relevant theories and technical indicators of frequency source synthesis,including frequency accuracy,phase noise,RF output power,and spectrum purity.At the same time,the related theories of phase-locked loop are introduced,and the basic functions and basic circuit composition of phase-locked loop are explained,which provides theoretical support and basis for the design of the subsequent X-band low phase noise multifunctional frequency source.This article introduces the design scheme and circuit realization of the X-band low phase noise multifunctional frequency source.In order to facilitate the design,starting from the design goals of the main performance parameters of the circuit,according to the working frequency band and function of the circuit,the whole module is divided into five types: phase-locked loop circuit,reference frequency circuit,mixer circuit,intermediate frequency circuit and power supply control circuit.section.The third chapter will first introduce the overall circuit scheme,and then divide it into five summaries to introduce these five circuits.Then the article introduces the relevant information of the X-band low phase noise multi-function frequency source test,and give the test results and analysis of the results in detail.The main test items are the frequency accuracy,phase noise and spurious rejection of the f0 signal,and the frequency accuracy of the f0±75k Hz signal is also tested.Although the main test items meet the index requirements,there is still room for improvement in terms of phase noise and spurious suppression.Finally,the article introduces the summary and explanation of the work content of this paper,and outlines the design method,implementation steps,component selection and design standards of this topic.Then,the prospects for future work are described,including the power supply of the phase-locked loop circuit,the spurious suppression of the output signal,and the phase noise of the output signal.In order to think about several main deficiencies in the design of this subject,in the future work,we will implement them one by one,and continue to work hard to improve the performance indicators of this module.