Research On Dynamic Spectrum Monitoring Technology In EMC Field Test

With the rapid development of electronic technology and the widespread application of electronic equipment,the electromagnetic compatibility(EMC)problem of electronic systems has become increasingly prominent,and electromagnetic compatibility testing has become more important.The certification test of some small integrated products is generally completed in the standard laboratory,but with the increasing complexity and application scale of the electronic system,the site and test conditions of the standard test can not accurately reflect the electromagnetic compatibility of the equipment during operation.It must be tested on site.The field test faces complex and changeable electromagnetic environmental noise and electromagnetic interference from peripheral equipment.It is difficult to monitor and capture the interference signals in the environment and obtain the emission information of the equipment or system itself,Therefore,The test plan and the test data processing plan have great research significance.In this paper,the electronic system in the complex electromagnetic environment is taken as the research object.During the joint debugging test of the system,the electromagnetic environment in the field is monitored in real time,and the working state of the electronic system is monitored.At the same time,the requirement of positioning the equipment with fault during the joint debugging of the system is taken as the research object to launch the research content of this paper.Firstly,according to the requirement of real-time monitoring of electromagnetic environment,especially the monitoring of transient burst signal in the joint debugging test of electronic system,the paper points out that the traditional sweep spectrum analyzer is easy to lose burst signal and the real-time performance of spectrum analysis is not good by analyzing and comparing the performance and advantages and disadvantages of various kinds of spectrum analyzer commonly used,so it is proposed that the real-time spectrum analyzer is used in the test scheme of this system.At the same time,the specific characteristics of the real-time spectrum analyzer are analyzed in detail,and a complete real-time monitoring scheme of electromagnetic environment is developed.Secondly,by analyzing the emission characteristics of typical electronic equipment in the electronic system,it is concluded that the typical characteristics of the spectrum curve of the equipment are peak characteristics,envelope characteristics and harmonic characteristics.This paper focuses on the first two spectrum characteristics,and gives the extraction process of the characteristic spectrum,which lays the data foundation for the subsequent positioning of the defective equipment.Then,the data of field test is analyzed,and the preprocessing process of the original data of field test is proposed.Aiming at the problems of traditional methods of interference source location,Dynamic Frequency Warping(DFW)algorithm is proposed,which solves the problem that when the template data of the same frequency band of the same equipment is inconsistent with the data points of field test,the traditional Euclidean distance algorithm cannot be used to directly match the spectral characteristics,which leads to the failure to locate the specific device.Finally,the paper gives the data processing flow of fault equipment location,obtains the template data of equipment a,equipment B and a certain type of motor in the shielded darkroom,obtains the field test data in the simulation test,verifies the feasibility of the DFW algorithm proposed in the paper,and compares and analyzes the results of the traditional feature matching method and the feature matching method based on DFW algorithm It is concluded that the test scheme and data processing algorithm proposed in this paper are suitable for this scheme,and can meet the needs of most electronic systems in joint commissioning test.