基于FPGA的DDS在雷达多普勒回波模拟中的应用

Application of DDS Based on FPGA in Radar Doppler Echo Simulator

分析了直接数字频率合成 (DDS)的原理 ,提出了利用现场可编程门阵列 (FPGA)实现DDS的方法 ,比较了利用FPGA实现DDS与利用专用DDS芯片实现的各自特点。针对某无线电引信实时动态测试系统的要求 ,采用DDS技术 ,利用FPGA产生了多个频率点、相差精确可调的两路多普勒信号 ,与载波进行单边带调制 ,得到的多普勒回波信号在各个频点均能很好地满足系统镜频抑制比要求 。

In this paper, The theory of DDS is analyzed, an effective method of realizing DDS using FPGA is suggested, and the characteristics of DDS based on FPGA and that of the special DDS chip is compared. According to the demands of a wireless fuserealtime dynamic testing system, we used FPGA to generate two Doppler signals of different frequencies and adjustable phases by DDS technology. The Doppler Echo obtained after SSB can better satisfy the requirement of the system mirror frequency suppression ratio for every frequency, and we performed the radar target echo's simulation and that of the fuse in many complex situations.