Design And Implementation Of Signal Receiving Module For Intrusion Detection System Based On Leaky Cable

Recently,the perimeter intrusion detection system based on leaky cable has attracted much attention of researchers and markets in security field because of its advantage of good security concealment,terrain fitting installation,omnibearing vigilance and all-weather work ability.As the front-end of signal receiving and signal processing of the leakage cable perimeter intrusion detection system,the performance of the signal receiving module directly determines whether the desired signals can be effectively received and has a vital impact on the normal operation of the system.The topic of this dissertation originates from the project " Key Technology Research for Perimeter Intrusion Detection System Based on Leaky Cables".In this dissertation,a type of Zero-IF quadrature demodulation receiver design method,which is suitable for the leakage cable perimeter intrusion detection system,is proposed.This method transforms high frequency signal into baseband signal for processing,which avoids the high cost of ultra-high speed AD devices used in the conventional design,and improves the performance of leaky cable intrusion detection system.The main work of this article are as follows: 1.A method for determining the signal receiving link structure and key link indicators of the leaky cable perimeter intrusion detection system is proposed.Comparing and analyzing the design methods?advantages and disadvantages of several receiver structures such as super heterodyne structure,image rejection structure,low-IF structure,zero-IF structure,and digital-IF structure.Based on the overall demand of the system,the zero-IF quadrature demodulation structure is chosen to build the signal receiving module.The overall indicators of the receiver such as link gain and baseband signal output power is given through a brief analysis.2.Design and implementation of the signal receiving link submodules,and integration of the whole receiving module.Based on the overall indicators of the receiver,the sub-module indicators is decomposed.According to each sub-module index,components selection and design are carried out.The schematic design?layout design and simulation of the sub module is carried out using MWO.Physical sub modules are realized through PCBs for performance debugging.MWO simulation results suggested that the receiver has 6.1dB noise figure and 72.6dB link gain in the 80-120 MHz working frequency band.The test results showed that the receiver has 7.6dB noise figure and 70.8dB link gain in the same working frequency band.The measured and simulated results of key link indicators are in a good agreement.3.Integration of the signal receiving module into the leaky cable perimeter intrusion detection system for system-level verification.The results of field experiments show that the perimeter intrusion detection system using this receiver can achieve its intrusion location function well,with a false alarm rate and omission rate better than 5% and a good positioning accuracy better than 10 m.The results of field experiments also indirectly verified the rationality of the signal receiver module design and the reliability of its performance.