Power Line Electromagnetic Information Leakage Protection Technology Based On Active Noise Interference

In recent years,with the continuous development of information technology,computer systems have been widely used in various fields such as production,life and military,and the information security of computer systems has received extensive attention.The information security of computer systems includes not only information leakage at the network and system levels,but also information leakage through electromagnetic radiation,especially the information leakage of display systems,which seriously threatens the information security of computer systems.The power line is an inevitable cable for the computer system,but due to the natural concealment of the power line,the leakage of electromagnetic information generated by the computer system through the power line is often ignored.Aiming at the leakage of electromagnetic information generated by computer systems through power lines,it is of great significance to design a protection scheme that is simple to implement and highly reliable.This thesis takes the computer display system as the protection goal,first analyzes the transmission mechanism of the video signal,and then simulates and tests the electromagnetic leakage characteristics of the video signal.According to the conduction coupling mechanism between the power line and the video line,the related technology of detecting the leakage signal from the power line is analyzed,and a fast detection method for the electromagnetic information leakage problem on the power line is determined.Research on the electromagnetic information leakage protection scheme of the computer display system,design an electromagnetic information leakage prevention device based on active noise interference,and verify the effectiveness of the protection scheme through tests.The main work and research results obtained in this thesis are as follows:By analyzing the working mechanism of the software and hardware of the HDMI interface computer display system,the leakage characteristics of the video signal of the computer display system are studied,and simulation and testing are carried out.The mainstream electromagnetic information leakage protection technology is compared and summarized,and the protection scheme of this thesis is established.Based on the analysis of the conductive coupling mechanism of the power line and the video line,the source of the electromagnetic leakage signal on the power line is determined.Through the research on the template matching related technology,a rapid detection method for the electromagnetic leakage signal on the power line is proposed,and it is aimed at LCD and LED.The electromagnetic information leakage of the display system was tested and verified.Through the analysis of the magnitude of noise injection and the study of white noise characteristics,a protection scheme based on active noise interference is determined.A white noise generation circuit is designed through simulation analysis.After amplification,the white noise is coupled and injected into the power line at 30MHz? A white noise interference signal with a power greater than-50 d Bm is formed in the 600 MHz frequency range.Analyze the application scenarios of the active noise interference device,use LISN and current clamps to detect the noise power injected into the power line,and verify the protection effect of the active noise interference solution,and also analyze the electromagnetic compatibility of the entire computer system.Through the above research,this thesis designs a white noise interference device,which realizes the effective protection of the electromagnetic information leakage of the power line,which is of great significance to the electromagnetic information security.