Implementation of an ultra-high speed 256-point FFT for Xilinx Virtex-6 devices

In this paper we present a parallel, FPGA-based implementation of a 256-point Fast Fourier Transform capable to perform over 78 million transformations per second. Its area of operation is located in the ultra-high speed OFDM communication in optical networks where the FFT algorithm provides the basis of the digital signal processing. The main focus lies on an implementation using as less as possible resources while ensuring the required high performance. However, to allow an adaptation of the core to different applications, a flexible adaptivity of internal bit vector widths was realized.