分析了罗兰C信号的特征,并根据信号特征决定选用FIR滤波器,利用MATLAB工具设计了满足滤波要求的高阶数字带通滤波器。详细研究了分布式算法的原理和分布式算法在FPGA上实现FIR数字滤波器的方法。最终采用改进的分布式算法在FPGA上实现了127阶FIR数字带通滤波器。利用实际采集的信号进行仿真和现场测试,结果均显示由该方法设计的滤波器性能良好,方法简单易行,相对于传统的乘累加结构不仅能节省硬件资源,而且可以改善数据处理速度,具有一定的推广价值。
The signature of the Loran-C was analyzed in this paper. The FIR filter was selected and a higher-order digital band pass filter was designed to meet requirement according to the Loran-C signature in MATLAB. The theory of distributed arithmetic and its FPGA implementation method were studied, At last, a 127 orders FIR digital band pass filter was realized using modified distributed arithmetic on FPGA. The simulation result using practical signal and the field tests showed the design is wonderful. The method is very simple, which not only used fewer hardware resources but also the speed is improved that can be widely popularized.