Diagnosis Of The Cuboid Device Internal Sources Of Electromagnetic Radiation Based On Wavelet And Independent Component Analysis

The mutual electromagnetic radiation interference generated during the operationof electronic equipment may affect the normal work of the equipment, and even causeserious damage on the equipment. The same situation will happen to the internal partsof devices. Therefore, it is necessary to ignore the electromagnetic interference of theexternal environment to establish the instrument internal electromagnetic radiationinterference model for the inside of device, and then propose a rapid and accuratediagnostic method of the internal sources of electromagnetic radiation interference.Based on this condition, the typical cuboids device’s internal electromagneticradiation case was taken as an example, then the mixed-signal processing method andinstrument simplified model of the internal electromagnetic radiation were analyzed, atlast an electromagnetic radiation diagnostic methods which is suitable for therectangular equipment was proposed. The main contents can be stated as follows.Firstly, a combination of wavelet transform and independent component methodconverged signal analysis method for processing mixed signals was innovativelyproposed, avoiding the problems when using wavelet transform and independentcomponent separation method signally. Taking the PC chassis for example, a mixedelectromagnetic signal analysis which mixed WT and ICA was presented which canchoose different ICA method based on the different characteristics of signals, and thespecial frequencies of the results was extracted by the wavelet function, at last theseparation result was achieved.Secondly, consulting some prior knowledge of the electromagnetic radiationsources which came from the inside of the equipment, a correspondence between theseparated mixture of electromagnetic radiation signal and the internal radiation wasestablished, then the amplitude and phase of the separation results were reduced, at last,the estimated radiation signals were obtained. Taking the PC chassis for example, aftercalculating and restoring the estimated emitter signals, the diagnostic method ofelectromagnetic radiation inside the cuboids equipment ultimately was concluded.Finally, according to the analysis of electromagnetic radiation interference generated from the various components inside the equipment, combined with theresonance features of the cuboids equipment, a simplified model of radiation inside theinstrument to verify the electromagnetic radiation diagnosis was proposed. Thecomputer case had been taken for an example in the thesis, after putting emitter signalswhich been found by the diagnostic methods as excitation source into the model, thencomparing the simulation results and the measured signal, the correctness of thediagnostic methods has been validated.The diagnostic method of device internal sources of electromagnetic radiationwhich had been validated by the simplified model had benefit to understand thecharacteristics of the instrument internal sources of electromagnetic radiation quickly,as well as improved instrument design and its anti-jamming performance.