Timeline for Why is the FFT "mirrored"?
Current License: CC BY-SA 3.0
15 events
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| S Nov 21, 2023 at 16:41 | history | edited | lennon310 | CC BY-SA 4.0 |
Added tags.
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| S Nov 21, 2023 at 16:41 | history | suggested | Rodrigo de Azevedo |
Added tags.
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| Nov 21, 2023 at 16:23 | review | Suggested edits | |||
| S Nov 21, 2023 at 16:41 | |||||
| Oct 31, 2012 at 18:31 | comment | added | Dilip Sarwate | What concerns me a bit is that the two bins have magnitudes $50.6665$ and $50.2971$. Theoretically, they should have equal magnitude $50.5$ as you say, but the difference is a little larger than I feel is attributable to round-off error. Could you re-run your program and tell us what the actual complex values are in those two bins? (Theoretically, the two bin values should be complex conjugates with imaginary parts close to $\pm 50.5$ and small real parts). | |
| Oct 30, 2012 at 19:15 | history | edited | Dilip Sarwate |
changed tag to dft since the question has nothing to do with the fft
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| Oct 29, 2012 at 21:38 | answer | added | Dilip Sarwate | timeline score: 31 | |
| Oct 29, 2012 at 0:03 | history | tweeted | twitter.com/#!/StackSignals/status/262706130994753536 | ||
| Oct 28, 2012 at 20:46 | answer | added | hotpaw2 | timeline score: 21 | |
| Oct 28, 2012 at 20:34 | answer | added | Jim Clay | timeline score: 52 | |
| Oct 28, 2012 at 19:55 | comment | added | endolith | Because a Fourier transform breaks up a signal into complex exponentials, and a sine wave is the sum of 2 complex exponentials. dsp.stackexchange.com/a/449/29 | |
| Oct 28, 2012 at 18:21 | comment | added | pichenettes | Ask yourself: what result would you expect if your signal was 1 + cos(2*pit)... And 1 + i cos(2*pit)... And 1 + i sin(2*pi*t)... | |
| Oct 28, 2012 at 18:02 | comment | added | WebMonster | For a pure real signals F(k)=conj(F(N-k)), this is why the Fourier transform of a pure real signal is symmetric. | |
| Oct 28, 2012 at 17:44 | comment | added | bobobobo | But this is specifically about the symmetry (I believe it's called Hermetian symmetry?) of the signal. | |
| Oct 28, 2012 at 17:35 | comment | added | pichenettes | A similar question has been answered here: dsp.stackexchange.com/questions/3466/… | |
| Oct 28, 2012 at 16:37 | history | asked | bobobobo | CC BY-SA 3.0 |