简要介绍了数字下变频的设计，通过采用xilinx的ise软件，ipcore的调用实现-Briefly introduced the design of digital down conversion, through the use of ise the xilinx software, ipcore call the realization of

基于FPGA的数字下变频器（DDC）的设计,将采样得到的高速率信号变成低速率基带信号，以便进行下一步的信号处理。由NCO、数字混频器、低通滤波器和抽取滤波器四个模块组成。采用自编的加法树乘法器，提高乘法运算效率。-Design based on FPGA digital downconverter (DDC), the high-speed signal will be sampled baseband signal into a low rate for the next step in th