The Active Millimeter Wave Security Inspection Radar Signal Generation, Acquisition And Transmission System Is Realized

As the most promising body security check technology,active millimeter wave imaging security radar has a very broad application prospect.Using wideband signals as the transmitting signal of security radar can effectively improves the radar’s imaging accuracy.In addition,the acquisition accuracy of echo signal,the accuracy of data transmission and storage process will also affect the imaging process.A new type of millimeter wave security radar is being designed by a reaearch institute now.This paper will design and realize its signal generation,acquisition and transmission system.The main work and contributions of this paper are as follows:System scheme design and signal generation algorithm simulation.Firstly,based on the functional requirements and technical indicators of the security radar signal generation,acquisition and transmission system,the overall design of the system is proposed.In order to improve the measurement accuracy and range resolution of the security radar,wideband LFM signal and step frequency signal are used as the system transmission signal.After analysis and comparison,FPGA and high-speed DAC are selected to generate wideband signal.Considering the limited working frequency of FPGA,a scheme of realizing signal generation by multi-channel parallel DDS is proposed,and the specific process of realizing broadband signal by this method is simulated by MATLAB,which verifies the feasibility and correctness of the scheme.Circuit design of the hardware board.Based on the analysis of hardware requirements,this paper designs the overall scheme of the hardware board.About the important parts of the design,this paper introduces their design ideas and implementation methods,including DAC circuit,ADC circuit,DDR3,clock system and power system.FPGA logic design and implementation.The system is based on FPGA platform,and the logic function of each module is designed by Verilog HDL.This paper introduces the process of chip configuration,the realization of multi-channel parallel DDS synthesis technology in FPGA,the design and implementation of signal acquisition module,DDR3 read-write control and PCIe3.0 bus interface transmission function.The important and difficult parts of the design are introduced in detail.System function debugging and verification.The performance of each functional module of the system is tested.The signal generation module can generate stable wideband signal,and the X-band wideband signals can also meet the requirements of the project;the signal acquisition module can collect the echo signal with a sampling rate of 400 MHz,and the acquisition results are correct;the transmission rate of the PCIe3.0 high-speed data interface can reach 4.55GB/s,which can fully meet the data transmission rate requirements of the radar.