Key Technologies For Wideband Radar Target Simulation System

Wideband radar target simulation system realizes the radar test by generating a variety of complex electromagnetic environment and target echo.The application of wideband radar target simulation system can effectively save the development cycle and cost of radar system.The key technologies of low-spurious and wideband radar target simulation system are studied in this thesis.Firstly,the hardware of a 1 GHz wideband and low-spurious digital radio frequency memory(DRFM)is designed.The modeling of wideband analog-to-digital converter(ADC)and digital-to-analog converter(DAC)is performed.On this basis,the factors affecting the performance of the system,such as quantization error,on-linear error and SINC function fading are analyzed and verified by simulation.The wideband RF receiver unit is analyzed while the influence of the oscillator harmonic and non-linear distortion of the mixer on the spurious performance is studied.The signal integrity and power integrity of the high-speed are analyzed.Secondly,according to the dynamic range of wideband radar target simulation system,the digital Automatic Gain Control(AGC)system is designed.The hardware design based on logarithmic detector,ADC,FPGA and digital variable gain amplifier is given.The design and implementation of the hardware circuit,control algorithm and the experimental verification are accomplished.The experimental results show that the dynamic range is better than 50 dB,the regulation accuracy is better than 0.5dBm,which can meet the the dynamic range requirement of system.Finally,the thesis carries on the experiment about the wideband DRFM performance and analyzes the testing results.The spurious free dynamic range(SFDR)of ADC,DAC and DRFM is given,and the factors that produce spurious are analyzed.The performance of mix mode is tested,and the amplitude-frequency curve is given by generating linear frequency modulation siginal.The results show that,between 0.1GHz and 1.1GHz,the SFDR performance is better than-50 dBc,which achieves the expected results.