：抽取是软件无线电中最核心部分。通过对多项抽取结构的分析，设计出一种多

级抽取滤波器的实现方案，并通过MATLAB仿真实现。

关键词：软件无线电；多相结构；多级抽取滤波器-: Extraction is the most central part of the software radio. By taking a number of structural analysis, design a multi-stage decimation filter implementation scheme, and Simulation by MATLAB. Key words: software radio　heterogeneous structure　multi-stage decimation filter