数字下变频基于FPGA的软件设计与实现

雷达的数字下变频功能主要是将天线接收到的中频回波信号通过A/D变换后,进行数字下变频处理,转为两路I/Q基带数据。本文主要设计了一种基于FPGA的数字下变频方法,通过对数字控制振荡器(NCO)及低通滤波器(FIR)的设计及实现,完成了对于不同频率本振信号的数字下变频处理。结果表明,基于该方案设计的数字下变频功能已在实际系统中得到应用。

The function of DDC is mainly to convert the signal received after A/D conversion by the antenna to Digital Down Convert（DDC）, finally into two I/Q baseband data. This paper mainly design a method about Digital Down Conversion based on FPGA, by designing the numerically eontrolled oscillator （NCO） and a low-pass filter （FIR）, to convert different frequency signal with DDC. The resuhs showed that the conversion function has been used in the actual system.