Quote:
Originally Posted by knc1
One of the (late in the day) references mentions that ifft only differs in the sign of e - meaning the fft only needs one more lookup table to get an ifft out of it.
When I wake up tomorrow, will see if I can spot that reference again.
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FFT ARM 0.0.1 - README
"Want an inverse FFT ? If you look closely at the formula for the FFT,
you'll see that the only difference between an FFT and its inverse is
the sign in the exponent of e. This means that *by reordering the output
alone* you can turn an FFT into its inverse. Again, it's been over three
years since I wrote this code, but have a look at TransTable in testmain.c
for more hints. My gut feeling is that you need the "In-place IFFT table".
thanks M. Yeah that was pretty much my thought process - look for the gaps to get the more relevant code happening.
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Have a great night