FFT IP Core: User Guide

ID 683374
Date 11/06/2017
Public
Document Table of Contents

1.3.1. Fixed Transform Size FFT

The fixed transform FFT implements a radix-2/4 decimation-in-frequency (DIF) FFT fixed-transform size algorithm for transform lengths of 2m where 6 ≤ m ≤16. This FFT uses block-floating point representations to achieve the best trade-off between maximum signal-to-noise ratio (SNR) and minimum size requirements.

The fixed transform FFT accepts a two's complement format complex data vector of length N inputs, where N is the desired transform length in natural order. The function outputs the transform-domain complex vector in natural order. The FFT produces an accumulated block exponent to indicate any data scaling that has occurred during the transform to maintain precision and maximize the internal signal-to-noise ratio. You can specify the transform direction on a per-block basis using an input port.