An efficient folded pipelined architecture for Fast Fourier Transform using Cordic algorithm

Abstract

Fast Fourier Transforms have become an integral part of any digital communication system and a wide variety of approaches have been tried in order to optimize the algorithm for a variety of parameters, primarily being memory and speed. Major problem in FFT calculation is the increased number of complex multiplication units. Folding transformations are used to design FFT architectures with reduced number of functional units. In the folding transformation, many butterflies in the same column can be mapped to one butterfly unit. A highly efficient pipelined folded FFT architecture for 8 point R2 FFT is presented here. When compared with the normal R2 FFT architecture, the pipelined architecture shows efficiency both in speed and area consumption. Futher reduction in the area can be obtained by using COordinate Rotation for DIgital Computer (CORDIC) algorithm, which is an add and shift algorithm that replaces complex twiddle factor multiplication. The FFT block is designed to be capable of computing 8 point FFT and employs R2 (Radix2) architecture which is simple, elegant and best suited for communication applications. VHDL coding is simulated and synthesized in Xilinx ISE Design Suite 12.1.