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General purpose FFT core

Product code: CMS0001

The FFT Core implements a FFT and inverse FFT suitable for use in Modulators or Demodulators for OFDM (COFDM) systems such as DVB-T/H, 802.11a and 802.16a.
It uses a fast and efficient radix-4 engine to compute the FFT. All logic is fully pipelined to clock at 4x - 7x sample rate, depending on FFT size.

Block diagram

General purpose FFT core block diagram (click to enlarge) Radix-4 FFT Engine block diagram (click to enlarge)
Click on diagram to enlarge


  • Synthesis control for any FFT size = 2n.
  • Synthesis control supports multiple sizes with run-time size selection.
  • Synthesis control of signal precision (variable width).
  • Performs forward and inverse FFT.
  • In FFT (forward) mode, inputs are gathered in time-order at sample rate. Outputs are produced in a burst at clock rate (4x - 7x sample rate).
  • In IFFT (inverse) mode, inputs are gathered in frequency-order at clock rate. Outputs are produced at sample rate.
  • Outputs are produced in sorted or scrambled order.