Cascade Division of Multi-type Filters in efficient Implementation of DDC

摘要

Based on the theories and techniques of Digital Down Conversion (DDC) in software radio receiver, this paper puts forward a new method to realize DDC by using cascade division of Multi-types filter. CIC (Cascaded Integrator-Comb) filter, two HB(Half-Band) filters and plastic FIR filter are involved in the realization of the decimation of DDC. The. requirements of multipliers and adders and the order of filters are reduced effectively. Meanwhile, the feasibility and validity of using the interpolated second-order polynomial (ISOP) filter in order to reduce the passband droop caused by CIC filtering with little degradation in aliasing attenuation sand are analyzed and validated in this paper, and the performance requirement of DDC is accomplished efficiently. Finally, the superiority of this technique is demonstrated by comparing it with the conventional method of FIR filtering.