Digital Signal Modulation Recognition Based On LabVIEW

With the rapid development of modern communication technology,the communication environment is becoming more and more complicated.In order to acquire better communication quality,the modulation mode,which is adopted by the communication signal in the frequency band,is becoming more and more complex.Modulation parameters are also different in different signals.Besides,it becomes increasingly important how to identify and monitor these signals quickly and efficiently.In a non-cooperative communication system,the accuracy and efficiency of a modulation method is the premise of subsequent signal demodulation,as well as signal processing.Automatic modulation recognition plays an important role both in the military field and in the civil field,and has attracted widespread attention of scientists.Neural network is a mathematical and computational model which takes the advantages of the structure and function of biological neural network.It is good at dealing with a large amount of parallel information and nonlinear mapping problems.Most importantly,it has good learning capabilities and plays a crucial role in intelligent control,pattern recognition and information processing.After half a century of research and development,neural networks have matured in theory and achieved excellent results in engineering applications.In recent years,artificial neural network research has been carried in many fields.This subject uses Lab VIEW to combine the characteristic parameter extraction algorithm with neural network technology,relative analysis and research has been carried on digital signal modulation and automatic modulation recognition.The main contents are as follows:Firstly,the research background of automatic modulation recognition technology,as well as the research status of automatic modulation recognition technology are introduced.Various analog and digital modulation methods in communication systems are thoroughly reseached.Four Time domain characteristic parameters and six frequency domain characteristic parameters are presented then.On the basis of this,combined with the LM-BP neural network classifier,the common 8 modulation schemes of digital signals are simulated.Finally,this subject uses software Lab VIEW and hardware USRP to set up real-time automatic modulation recognition,the results are satisfactory.