Research On Frequency Synthesis Technology In Millimeter Wave Signal Analyzer

Signal analyzer is a basic electronic measuring instrument,it's widely used in communication,microwave,aviation and other fields,and it runs through the research and development,production,acceptance,certification and other links.Frequency synthesizer is one of the core components of signal analyzer,which can provide local oscillator,clock and other signals for other modules,and has an important impact on system performance.On the other hand,as a measuring instrument,the signal analyzer has high requirements on the frequency range,resolution and spectrum purity of the frequency synthesizer.In recent years,with the rapid development of the fifth generation mobile networks(5G)millimeter wave,satellite communications,radar and other fields,the demand for the frequency range of signal analyzer is also extended to the millimeter wave band.In this paper,under the support of the National Science and Technology Major Project "Development of Millimeter-wave 5G Analyzer",the frequency synthesis technology of millimeter-wave signal analyzer is studied.The basic principles of different frequency synthesis techniques are studied in this paper,and the phase noise index in frequency synthesis circuit is analyzed emphatically,which provides a theoretical basis for the scheme design,device selection and performance analysis of millimeter wave frequency synthesis.According to the requirements of the overall scheme of the 400MHz-76 GHz signal analyzer for local oscillator,clock and reference,the following functional modules are developed in this paper: 1)multi-output point frequency module.This module uses the PLL frequency synthesis technology,combined with the frequency multiplier,frequency division and other processes,to achieve a variety of high stability,low phase noise point frequency signal output such as 100 MHz,491.52 MHz,983.04 MHz,3072MHz,3932.16 MHz,7864.32 MHz and 10 MHz reference clock output.2)Broadband local oscillator module.This module includes two submodules:(1)Broadband frequency synthesis submodule,it adopts the direct digital frequency synthesizer to excite the phase locked loop,and improves the phase noise performance within the loop bandwidth of the system output signal through two down converters in the phase locked loop.The output frequency range of the sub-module is 8?16GHz,and the frequency resolution is 1Hz;(2)Broadband frequency multiplication sub-module,it splits the input signal frequency band through the radio frequency switch,carries out frequency multiplexing,filtering,power amplification and equalization in different frequency bands,and finally realizes the broadband signal output from 8 to 39.5GHz through the integration of the frequency band.This paper has completed the design and processing of the modules required by the subject,and tested the relevant indicators.The developed module has passed the joint commission and has been applied in the millimeter wave signal analyzer prototype.