FFT core
FFT core
(OP)
I need an FFT/IFFT core of radix3 for our project. I cannot use radix2 or radix4. Is it possible to implement such an FFT core on a programmable logic device? I need tips
Thanks in advance
Thanks in advance
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RE: FFT core
RE: FFT core
<nbucska@pcperipherals DOT com> subj: engtips
read FAQ2401032
RE: FFT core
Is it necessary to do it? Can't you convert after you done it in base 2? That's the standard solution.
RE: FFT core
on the market. The only thing you save are a few lines...
Or is this a school project?
<nbucska@pcperipherals DOT com> subj: engtips
read FAQ2401032
RE: FFT core
2 lines for each ternary digits ( I don't think you
can find FPGA with three level inputs).
What kind of speed do you need ? Where do you
get the ternary data from?
<nbucska@pcperipherals DOT com> subj: engtips
read FAQ2401032
RE: FFT core
I think you can apply the standard CooleyTukey implementation which gives a good solution for size 2^n, 4^n, 8^n etc. which I have used for radix2, radix4, and radix8 as well as mixed radix FFTs but never for 3^n sized ones.
I googled and got some hits for "radix 3 FFT" so I know there are reasons to use it.
RE: FFT core
The radix is the base number of points you are going to use. So really there is no 2 point FFT. Its a 2 point DFT (it can't be broken down any smaller) A 3 point DFT can't be broken any more either (it is prime). A 4 point transform can either be a radix 4 algorithm or it can be radix 2 (2 twos that are combined). If you use only 3 point DFT's to do a FFT it's a radix 3 based FFT. If you use different size DFT's to build up a FFT it is called a mixed radix algorithm..
You use these different radix algorithm so you don't have to zero pad you input vector. For example if I have 96 points I could use 5 levels of 2 (32) and one level of three. If I stay strictly with a radix algorithm I have zero pad my vector out to 128.
Steve