Research On Equalization Correction And Trigger Capture Function In Real-time Spectrum Analysis

With the rapid development of modern radio frequency technology,broadband Real-time spectrum analyzer has got more and more attention.The channel group delay can cause phase distortion and affect the modulation domain analysis.A powerful trigger capture function ensures a test requirement for instantaneous small probability signals.The main content of this thesis is to study the method of group delay equalization correction and trigger capture function in real-time spectrum analysis.Firstly,the thesis introduces the significance and research status of group delay correction and triggering storage in Real-time Spectrum Analysis.The group delay correction of channel filter is based on the method of single Channel filter group delay test.Get the expected group delay first,and then according to the relationship between the group delay of the digital all-pass filter and the group delay of the denominator,the coefficient of the denominator polynomial will be worked out,and the transfer function of the digital all-pass filter will be confirmed.There are four trigger sources including the frequency of mask trigger,and single or continuous trigger mode for users to choose.The storage system bases on external DDR3 SDRAM,designs the different trigger depth according to user's requirements.The baseband I/Q signal will be stored in the DDR3 circularly without interruption.The stored signal will realize up to 98% overlap rate of overlapping frame processing according to the requirement of the user's overlap rate by changing the read address.The thesis carries on the simulation and the verification of the channel group delay correction and the trigger memory module design.Through the analysis of theory and result,it verifies the feasibility of the group delay correction method with the digital all-pass filter,and the realization of trigger memory module function,the design requirements is satisfied.