讨论了软件无线电接收机中数字下变频处理的高效算法和结构,其目的是在DSP中用软件完成数字下变频处理,这样可省去专用数字下变频器硬件集成电路,并增强中频处理的灵活性、适应性。针对软件数字下变频中滤波-抽取的运算量的考虑,文中提出了用W alsh变换替代传统的用FIR滤波器抗混叠滤波的方案,实验结果表明该方案可有效节约数字信号处理器的时间和空间。

Digital down converter is a key component in digital receivers.Sampling rate of converter deserves to pay attention.An efficient decimation architecture based Walsh transform for HF surface wave radar receivers is presented.The proposed DDC takes into consideration the complexities of algorithm due to the relatively high data rate and the intensive filtering operations involved in commonly used decimators,which substitute multiplication-addition for addition-subtraction imposed on filter.Performances are compared with that of other similar decimators.Experiment results show that the new decimators outperform others,so they are suited for real time signal processing in DSP,such as ADSP21060.

TN958 TN957.5

国家“863”高技术研究发展计划资助项目(编号2004AA604080)