基于FPGA的数字下变频设计

Design of Digital Down Conversion Based on FPGA

理想的软件无线电系统需要尽可能地减少模拟环节,而将数字化处理(包括A/D,D/A等)尽可能靠近天线端。数字下变频(DDC)系统作为ADC与DSP器件之间的桥梁,主要用来实现对前端高速A/D采集到的中频信号进行混频、降速和滤波,完成信号的下变频处理。鉴于FPGA在工程上的可实现纯并行运算、速度稳定可靠等优点,完成了数字下变频的电路设计和下变频系统多级滤波结构的设计。

The ideal software radio system needs to minimize the analog part,while the digital processing(including A/D,D/A,etc.)should be as close to the antenna end as possible.Digital Down Conversion(DDC)system,as A bridge between ADC and DSP devices,is mainly used to realize frequency mixing,speed reduction and filtering of intermediate frequency signals collected from the front-end high-speed A/D,and complete down-conversion processing of signals.Given the FPGA can be realized in engineering pure by its parallel computing,it completes the circuit and multi-stage filter structure design of the digital down conversion.