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Altera_Forum
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13 years ago

why fft core's output is conjugate

Dear all, When I using quartu12.0's fft megacore IP, I found such problems: chose variable streaming and natural order for both input and output order, set ifft, make si...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

It could be your understanding of ofrequency sense is wrong between matlab model and ifft core.

You got cos waveform on real ifft output and -sin waveform on imag ifft output.

This means your so called impulse is one nonzero sample at a negative frequency location i.e. after midpoint of 1024 (well further from sample 512) .

So in which sample did you put that impulse?