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AR# 63525

LogiCORE IP LTE Fast Fourier Transform v2.0(Rev.6) - The overflow flag is not asserted when it occurs


When the IP is configured with a Burst I/O architecture, scaling, bit-reversed output, and an overflow output (and the point size is 1536), the IP might not flag overflow when it occurs.

The C model for the IP is not affected and functions as expected. 


This is a known issue with LTE Fast Fourier Transform v2.0.

One possible work-around is to use natural-order output.

This works because the control logic used is different to the bit-reversed output case, and the natural-order output logic behaves as expected. 

A second work-around is to avoid overflow by using a conservative scaling schedule.

See the IP product guide for details.

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Master Answer Records

AR# 63525
Date Created 02/09/2015
Last Updated 02/16/2015
Status Active
Type General Article
  • Vivado Design Suite - 2014.4
  • LTE Fast Fourier Transform