Hello,
I am finding that FFTs with sizes <= 2^11 work fine, but >2^11 are producing
invalid output. Roughly, a CW complex tone is appearing at two frequencies
instead of just at one. I can reproduce this in simulation and in the lab.
Andrew suggested this may be due to the MaxCoeffNum, and I now remember I
ran into this problem before but never got around to solving it. I
understand the idea behind MaxCoeffNum, that for large FFTs the differences
between twiddle factors become small enough that they can be neglected.
However, as it is currently implemented, it does not seem to work. I am
using the green 7.1 blocks. Has anyone successfully used this feature (i.e.
made a single input biplex FFT of length greater than MaxCoeffNum, 2^11 by
default)?
Thanks,
Glenn
