The Research And Hardware Realization Of Modulation Identification Of Communication Signals System

Modulation identification of communication signals is a very important technique elements in non-cooperative communication and Software Defined Radio.Non-cooperate communication is commonly used in civilian and military applications,where it is required to monitor the activities of communication signals in space and intercept the signal information content with little prior knowledge. Software Defined Radio is a key technique in future communication, which requires the receiver to work in multi-mode and multi-band based on a same hardware platform.It is necessary to solve the problem of recognizing the modulation type in both applications.This paper extracts the characteristics that identified modulation type efficiently and gets the identification algorithm of analog modulation and digital modulation by theoretic simulation in MATLAB.Comparing with three different hardware systems of ARM, DSP and FPGA, and then the hardware platform based on DSP and CPLD are designed and executed. Software are designed on the basis of this hardware platform,achieving the identification algorithm such as FFT and Hilbert transform in DSP,and realizing the sequential logic control among DSP,FIFO and FLASH in CPLD.The hardware circuit is finished and debugged, getting the relationship of recognition rate and SNR for four analog modulation of AM,DSB,SSB,FM and five digital modulation of 2ASK,2FSK,2PSK,4ASK,4FSK in different SNR, realizing the off-line real-time identification to AM and FM modulated signals.