Flexible down-sampling using CIC filter with non-integer delay
Djordje Babić, Markku Renfors · 2003
In this paper we present an efficient structure for flexible downsampling in multistandard radio receivers. It is based on Cascaded Integrator-Comb (CIC) filter that has very efficient implementation structure without multipliers. By using non-integer delay in the feed-forward branch of comb stage and polynomial interpolation filter between integrator and comb stages of CIC we achieve improved attenuation for the aliasing frequency components. The fractional delay that is placed in feed-forward branch of comb stage introduces some extra requirements for design and implementation. The main advantages of the proposed structure are flexibility and programmability.