cic抽取滤波器ip核，用于射频采样数字下变频模块的核心数字信号处理部分.此ip核已经过ise10.2验证,CIC decimation by 4 filter，used in Direct RF sampling of GPS signal. the core dsp block in a frondend design

gps射频直接采样的捕获代码,实际采集数据的-RF direct sampling acquire