The System Design For The Acquisition And Processing Of Electromagnetic Signal In The Interface Of Electronic Communication Equipment

The development of electronic communication equipment has brought great convenience to people's life,but the ensuing electromagnetic information leakage is a serious threat to the security of personal privacy and national information security.Research shows that,in addition to the common mode circuit of the computer keyboard and its interface leakage information,other electronic communication devices and their interfaces,such as printer serial communication will also outward radiation that contains electromagnetic signals of character information.Although in the past,there were many the theories of electronic communication equipment and its interface electromagnetic information leakage,it has not been a complete set of hardware and software to intercept electromagnetic signals and restore the effective information.From the point of view of practical application,the design of the signal acquisition and processing system of electronic communication equipment interface is of great significance.The main work of this paper can be summarized as follows:Firstly,the research based on intercepted printer serial port leakage electromagnetic signal,analysis of mode of the signal encoding and restoring,and the design of low speed signal processing circuit for the signal filtering,amplification,AD sampling and processing,the circuit includes low speed signal amplification circuit,active filter circuit,AD sampling circuit,digital signal processing circuit.Secondly,the research based on the technology of complex electromagnetic signal isolation,through the independent design of PS/2 interface leakage signal acquisition circuit,we can acquire leaking character information from PS/2 interface computer,and use software named the Cadence designing the high speed data acquisition card to processing the leaking information.High speed data mining truck design including high speed signal processing circuit design and PCB design.Finally,we use EMSCAN IV to the measure and analyze electromagnetic compatibility of the PCB board,and to provide data to support for the next improvement of circuit board electromagnetic compatibility.Finally,the paper introduced VHDL which is developing language of FPAG and the development environment,the language design intercepted information recovery process based on the language,and successfully restored PS/2 interface leak information.