Research And Implementation Of The Multi-channel Digital Channelized Receiver Technology

Electronic warfare receiver can intercept the enemy's non-cooperative signal.Through the analysis of these signals,effective strategic help can be provided for friendly.With the development of modern electronic warfare technology,the electromagnetic signals in the space become more and more complex.These signals have large pulse density,wide energy distribution,and may arrive at the same time.Digital channelized receivers are widely used in electronic warfare because of their wide bandwidth,high sensitivity and the ability to intercept time-domain overlapping signals.In this paper,a multi-channel digital channelized receiver technology is studied and implemented.The receiver can effectively receive the signal in the range of 1250 MHz ~ 1750 MHz,and realize the uniform channel structure in the frequency domain by using the polyphase filter bank and the Inverse Discrete Fourier Transform.On the basis of this,the signal detection,pulse parameters and the type of modulation extraction is finished under low signal-to-noise ratio.Finally,the formation of pulse description words is forwarded to the follow-up signal processing unit.Based on these studies,the FPGA implementation of the multi-channel digital channelized receiver is completed,and the test and verification is completed on the hardware platform.The main content and innovation of this paper is as follows:(1)The multi-channel digital channelized design is completed to measure the phase difference between channels.The design improves the measurement accuracy and sensitivity of the back-end directional receiver.Aiming at the problem of phase consistency between multi-channels,a multi-chip ADCs synchronization method is proposed,and FPGA IO_DELAY is used to guarantee the signal receiving stability.(2)On the basis of digital channelization,the method of amplitude autocorrelation is used to improve signal-to-noise ratio again.A detection method based on dynamic threshold is proposed to update the threshold in real time according to the change of signal to noise ratio.The signal envelope can be effectively extracted,which can provide the basis for pulse parameter measurement and signal modulation type recognition.(3)Using the method of state machine detection,two signals which arriving at the same time are extracted.The information,such as envelope,IQ and frontier frequency and parameter measurement,pulse modulation type of each signal are stored and forwarded respectively.Based on the hardware platform,the design of multi-channel digital channelized receiver is completed on a FPGA(Virtex-7 XC7VX980T).The design is proved to be stable and reliable through the test.