Forward/Inverse and Scaling Schedule - 9.1 English - PG109

Fast Fourier Transform LogiCORE IP Product Guide (PG109)

Document ID
PG109
Release Date
2025-06-11
Version
9.1 English
The transform type (forward or inverse) and the scaling schedule can be set frame-by-frame without interrupting frame processing. Both the transform type and the scaling schedule can be set independently for each FFT channel in a multichannel core. Each FFT data channel has an assigned FWD_INV field and SCALE_SCH field in the Configuration channel. Setting the FWD_INV field to 0 produces an inverse FFT, and setting the FWD_INV field to 1 creates the forward transform.
Note: Due to architectural limitations, forward or inverse FFT cannot be controlled by the runtime configuration channel for native floating-point and Fixed-point SSR>1 implementations. There is a design-time check box on GUI to control forward and inverse FFT in these architectures.

A scaling schedule is not required (SCALE_SCH is ignored) when the FFT core is configured to process floating-point data. Normalization and scaling are handled internally for floating-point data.