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Altera_Forum
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11 years ago

FFT_verification

Hi ! When I run FFT and IFFT tool in megawizard, the results are not logical. For example firstly I run the FFT tool with the megawizard tb (input: natural order, output : digit reversed order)...
Altera_Forum's avatar
Altera_Forum
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11 years ago

Hi ferdiskaras,

I guess I have the same problem you went through. I have implemented a VARIABLE STREAMING (N=8), SINGLE-FLOAT-POINT FFT/IFFT. These are my results:

input (natural order): (8 0 0 0 8 0 0 0)

FFT

output (Digit-reverse order): [16 16 0 0 16 16 0 0] /* the same as [16 0 16 0 16 0 16 0 ] Natural order */

input(Digit-reverse order): [16 16 0 0 16 16 0 0]

IFFT

output (natural order): (64 0 0 0 64 0 0 0)

How did you normalize it? Where did you make de division by N? In your hardware or in your software? Is there a way to set FFT core to output data already normalized?

Thanks