宽带雷达信号的低杂散采样系统研究

Low Spurious Sampling System of Wideband Radar Signal

为了实现宽带雷达系统中雷达信号的低失真采集与处理,研究并设计了具有幅相误差校正功能的宽带低杂散采样系统。该系统采用宽带模数转换(Analog to digital converter,ADC)器件和高性能可编程逻辑阵列(Field programmable gate array,FPGA)的实现方案,并从低抖动采样时钟、低噪声电源和防串扰等方面进行了低杂散最优方案研究。为了改善系统的带内传输特性,利用优化算法设计了有限长冲激响应(Finite impulse response,FIR)数字校准滤波器。最后对设计的系统进行实验测试,结果表明系统瞬时带宽达到800 MHz以上,采样率1.8GS/s,量化位数8位、杂散电平-50dBc,性能指标满足系统在宽带雷达信号获取、宽带雷达目标成像和宽带雷达目标回波重构等领域的应用。

In order to realize low distortion acquisition and processing for wideband radar signal in the wideband radar system, a wideband and low spurious sampling system with amplitude and phase correction is studied and designed. The system uses the implementation scheme of wideband analog to digital converter （ADC） device and high performance field programmable gate array （FPGA） device, which is researched from low jitter sampling clock, low noise power, anti crosstalk for the optimal low spurious performance. To improve the band transmission characteristics of the system, a finite impulse response （FIR） filter is designed based on optimization algorithm. Finally, the designed system is tested in lab, and the experiments results prove that the spurious-free-dynamic-range （SFDR） of the system is characterized as -50 dBc worst-case over an instantaneous bandwidth of more than 800 MHz, sampling rate of 1.8 GS/s, quantization length of 8 bits. System performance levels meet the application requirements of wideband radar signal acquisition, wideband radar target imaging and wideband radar target echo reconstruction.