The Monitoring Of Radio Digital Signal And Using In Exam Security

Analog signal monitoring is the primary method used by traditional radio monitoring.It scans the perceptual signal through the frequency band,uses the intermediate frequency survey to the captured signal,demodulates the pronunciation,and finally enables the radio monitor personnel to judge the signal type through the method of listening to the pronunciation.In recent years,with the development of digital radio communication technology,digital wireless communication is getting more and more applications in all walks of life due to its low power consumption,long transmission distance and strong anti-interference ability.At the same time,a large number of outlaws also use this measure to engage in illegal radio activities.Therefore,current radio monitoring needs to go from the monitoring of analog signals to the monitoring of digital signals.Digital signal monitoring is more difficult than analog signal monitoring.It requires more accurate signal detection capability and needs to complete signal demodulation and decoding.Therefore,radio digital signal monitoring is a very active research field in radio monitoring and management.Based on years of practice in radio management,this paper summarizes the contents of digital radio monitoring in the field of radio supervision,analyzes a variety of digital signal protocols,and designs and develops a prototype system for test support.The main work of this paper includes the following points:(1)Summarized and introduced the radio digital signal monitoring.The principle of radio monitoring and radio digital monitoring system is introduced.The key technologies of digital signal monitoring based on software radio technology are also introduced,which is the systematic selection of this paper.(2)Summarized the principle of digital intercom,the demodulation and decoding technology of digital walkie-talkie signal.Designed the monitoring program of software radio digital walkie-talkie based on the USRP platform,and realized the prototype system and a variety of formats of digital talkback signal monitoring.(3)Analyzed the cheating technology of exam digital signal,and designed and developed the examination support system.The system automatically performs frequency band scanning,automatically finds new signals,performs intermediate frequency measurement,and automatically completes the data storage and playback.It can save,demodulate and decode the digital signal data,and realize the visual display of the transmission content.Finally,this paper summarizes and prospects the work.This paper uses software radio technology to achieve radio digital signal monitoring,has a certain novelty,and has certain reference significance for the development of small radio monitoring system.The main task of the future is to achieve the unified implementation of the two kinds of systems,and to develop more practical wireless digital signal monitoring system.