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Altera_Forum
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17 years ago

Help with altera FFT

hello; what i want to do is to get spectrum of an sinusoidal signal using the altera fft core i have generated a v8 fft with the following setting: fft point : 64 (to start with) archi...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

I think my FFT is working in general for analog audio input. I have increased the FFT resolution from 256 points to 512 points, however, I don't seem to notice much difference in the output.

Also, how come for some frequency inputs, I get one pretty clean spike, but for other frequency inputs, the spike fans out at the bottom, with two or more spikes in adjacent bins and/or the amplitude fluctuates a little? My input is always one constant sine wave. For example, at 1335Hz, the spike is very sharp and good, but at 1260Hz, I get two spikes at about 4 bins apart and their magnitudes fluctuate just a little.