Development Of A Wideband, Low Phase Noise And Small Step Frequency Synthesizer

In recent years,with the rapid development of radio frequency microwave system such as radar detection,satellite communication and electronic countermeasures technology,the market has put forward higher demand for the frequency band,phase noise,spurious and frequency resolution of the frequency synthesizer.According to recent research,the development of frequency synthesizer at home and abroad in recent years,How to balance the relationship among indicators such as spur level,phase noise,frequency jumping time and frequency resolution is a major contradiction to be solved for broadband frequency synthesizer.This paper is based on the design theory of hybrid frequency synthesis technology to design the Frequency Synthesizer with wide-band low phase noise and fine frequency resolution.This topic uses comb spectrum generator and advanced phase locked loop to ensure low phase noise index requirements.Direct digital frequency synthesis technology(DDS)is used to ensure the requirements of small frequency resolution.Finally,the spread spectrum module was designed to achieve the operation frequency indicators of wide-band.From the final test results,in the frequency range of 250MHz?8GHz,the full frequency output frequency step can reach 1Hz,spurious<-70dBc,phase noise is better than-105dBc/Hz@1kHz,and the output power is above OdBm.This paper first introduced the research background,significance of this paper and arrangement;then,introduced the basic principle,main frequency synthesis technology and analyzing the advantages and disadvantages of the main application requirements;According to the indicators of the project,carried out the demonstration of the wide-band frequency synthesizer,including the overall plan,the guarantee of key indicators such as phase noise,and the selection of key chips.;after each part of the system was detailed designed and realized;finally,to complete the design principle diagram and PCB layout of each module,hardware processing,debugging and testing the components and systems,and analyze the test data.Finally,in view of the shortcomings of the design,this paper puts forward some suggestions for improvement.These design methods and suggestions for improvement are valuable for achieving a high-performance frequency synthesizer with wide-band low phase noise small frequency resolution.