A Flexible-Channel MDF Architecture for Pipelined Radix-2 FFT

This paper proposes a flexible-channel multiple-path delay feedback (FC-MDF) pipelined fast Fourier transform architecture, which is based on Radix-2 FFT algorithm. The FC-MDF can be dynamically configured to accommodate two levels of FFT size. Different from the bypass structure that prevents the sequence data from passing through the preceding stages when the FFT size is reduced, the FC-MDF can be dynamically configured into single-channel mode when calculating larger size sequences, and into dual-channel mode when calculating smaller size sequences by taking advantage of the first stage 0and sharing of processing elements in subsequent stages. The proposed architecture increases the utilization of computing units, including butterfly and complex multiplier, from 50% to 100%, and provides twice the throughput in dual-channel mode, compared with the traditional Radix-2 single-path delay feedback (R2SDF) architecture. We implemented this structure on Xilinx FPGAs. The experimental results show that, compared with current SDF, the proposed FC-MDF significantly optimizes the proportion of resources when the FFT size is reduced.