Exploring the latency-resource trade-off for the Discrete Fourier Transform on the FPGA

This paper provides a novel way of trading increased resource utilisation for decreased latency when computing a single Discrete Fourier Transform on the FPGA. Analysis conducted on the Cooley-Tukey FFT optimisation shows that it increases the number of operations in the critical path of the transform computation. Consequentially an algorithm is proposed which allows control over the degree to which the Cooley-Tukey optimisation is utilised, trading between resource utilisation and absolute latency. The resource utilisation and latency results for the MyHDL implementation of the proposed algorithm upon the Rhino platform are provided which demonstrate that a practical Pareto curve has been established for a variety of dataset sizes. This implementation is also compared to Xilinx´s FFT IP core, providing 14% better latency performance than the manufacturer´s implementation albeit at a greater resource cost.