基于多相滤波的宽带信号DDC技术

Digital Down Conversion Technology for Wideband Signal Based on Polyphase Fitering

基于对多相滤波结构的改进,提出了一种宽带信号的数字下变频方法。该方法采用高速采样芯片ADC12D1800实现中频采样,采样数据分多路输出,结合多相滤波结构有效降低数据率与处理速率,实现了数字下变频与抽取功能,解决了高速采样与低速数据处理不匹配的问题。设计方案在Altera公司的Stratix IV系列FPGA上进行了仿真验证,并与传统的DDC进行比较。结果表明,该数字下变频方法运算量减少,FPGA内部逻辑资源的消耗减少,具有可行性和实用性。

Digital down conversion for wideband signal is introduced based on polyphase filtering,optimizing the existing implementation scheme. Wideband signal is sampled by the ADC12D1800 and the output signal is divided into several groups,which can achieve achieves digital down conversion and decimation combined with polyphase filtering. This method can effectively reduce the data rate and the data processing speed,solving the problem of the mismatch between the high sampling rate and low processing speed. This design is simulated in Altera Stratix IV FPGA,and compared with the traditional DDC. The result shows that the benefits of the optimization for architecture of DDC includes lower operations amount,less consumption of FPGA resource. The new scheme is feasible and practical.