Study On The Design Of Intelligent Test System Of Electromagnetic Interference

The study and problems solving of electromagnetic compatibility(EMC) in engineering are established on numbers of test of experiment. It needs experiment to analyse and judge if there are problems of electromagnetic interference(EMI), and how to evaluate the equipments under test(EUT). At present, most of the EMI test has low efficiency and poor reliability because of manual testing. Therefore, it needs a suit of intelligent test system(ITS) which tests the EMI of EUT accutately with normal equipments of laboratory. Then, the ATS can improve the repeatability of testing and reduce the high expense of test. For the moment, electromagnetic radiation test(EMRT) is carried in anechoic chamber or shielding room, whereas, many large equipments or some equipments installed in locale can't enter the chamber. Besides, the cost of test in the anechoic chamber is high.The wavelet transform ITS based on intelligent instrument was proposed in the paper. It comes from the technical development of automatic test of EMC, and the key research is filtering the ambient noise in the urban environment which is polluted by electromagnatic waves. Mordern digital signal processing technicals are applied to anylyse and process the testing signal in the ITS based on LabVIEW. At first, design the structure and function flow of ITS in LabVIEW, then complete the test system platform of hardware. The second, construct the wavelet function to analyse the detail of the testing signal, which can reduce the ambient noise such as radio wave perfectly and reconstruct the signal. The program which running in the LabVIEW platform control the genaration, analysing and record of the signal. The ITS based on LabVIEW improves the accuracy and efficiency and reduces the cost of test in the EMI test in anechoic chamber. A threshold function was constructed in the digital signal processing theory based on wavelet analysis. The ambient electromagnetic noise was perfectly removed. Because of the introduction of intelligent instrument technique and advanced digital signal processing technology, the system has short exploitation periods and high efficiency.The innovative method was proposed that tests the EMI of the EUT transfering the advanced digital signal processing module in the LabVIEW, and analyse the test results and bring forward the useful steps to make the EUT eligible. Then, propose the standard of ships with cutting the GJB. It saves much cost of EMI test as well as improves security of the EUT. At the same time, the study harvest has great value to applied in the engineering.