Radiation EMI Noise Analysis And Diagnosis Method Based On ICA And STFFT Algorithm

With the rapid development and progress of contemporary society,the characteristics of modern science became high frequency, high speed, high sensitivity, high mounting density and high reliability. Different kinds of electronic equipments had penetrated into every area including industry,agriculture, military and family.The electromagnetic environment became increasingly complex,which makes the human living environment worsen.The existing analysis methods can only analysis the radiation issues from the aspects of theory and modeling which can’t locate the radiation source and there is a certain error between the theoretical result and actual situation.Therefore,the diagnosis and analysis of electromagnetic interference for complex electronic equipment become the biggest challenge of EMI malfunction analysis.In this paper,a novel noise diagnosis method for complex electronic equipments based on signal analysis was presented,including three parts as following:(1)The radiation mechanism of complex electronic equipment was analyzed started with the basic theory and a novel diagnosis method for electromagnetic interference based on signal analysis was proposed.(2)The radiation diagnosis and analysis method for complex electronic equipments was put forward.Applying the ICA algorithm,the near field time-domain signals, resulted from superposition of multiple radiation sources,can be separated into several independent noises as alternative noise.Through joint time frequency analysis,the features of radiated noise can be extracted and the components which caused noise exceeding can be located by comparing the feature with EUT.(3)This paper applies the method in three, rapidly diagnozed causation and made the radiated noise below the standard threshold.The feasibility of the approaches was verified through three experiments which applied the method in double CM mixed source,double DM mixed sources and CM/DM mixed source.The validity of the method is verified by application example in complex electronic equipment which rapidly diagnosed causation and made the radiated noise below the standard threshold.The theory and experiment results show that the radiated EMI noise issue in complicated electrical equipment can be resolved applying the diagnosis method proposed in this paper.With this method,the mainly causation of emission exceeding can be located and specific rectification can be provided.In the meantime,this method may offer a reference for tracing method of complex electronic equipment and multiple radiation sources rectification in the future.