Xilinx, Inc.
Streaming FFT with bypass function

Abstract:

Embodiments herein describe an FFT that can bypass one or more stages when processing smaller frames. For example, when all the stages in the FFT are active, the FFT can process up to a maximum supported point size. However, the particular application may only every send smaller sized frames to the FFT. Instead of unnecessarily passing these frames through the beginning stages of the FFT (which adds latency and consumes power), the embodiments herein can bypass the unneeded stages which reduces the maximum point size the FFT can process but saves power and reduces latency. For example, the FFT can have selection circuitry (e.g., multiplexers) disposed between each stage that permits the input data to either bypass the previous stage(s) or the subsequent stage(s), depending on the architecture of the FFT. The bypassed stages can then be deactivated to conserve power.