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Both sides previous revisionPrevious revision | Next revisionBoth sides next revision | ||
time_series:fft [2014/08/11 21:22] – phreazer | time_series:fft [2014/08/11 21:25] – phreazer | ||
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$e^{-x} = \cos x - i \sin x$ | $e^{-x} = \cos x - i \sin x$ | ||
- | $X[k] = \sum^{N-1}_{j=0} X[n] \cos(\omega_k * n) - i \sum^{N-1}_{j=0} X[n] \sin(\omega_k * n)$ | + | $X[k] = \sum^{N-1}_{n=0} X[n] \cos(\omega_k * n) - i \sum^{N-1}_{n=0} X[n] \sin(\omega_k * n)$ |
$\omega_k= \frac{2 \pi k}{N}$ | $\omega_k= \frac{2 \pi k}{N}$ | ||
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Maß für Anwesendheit von Cosinus (Reelle Zahlen) / Sinus Wellen (Imaginäre Zahlen) | Maß für Anwesendheit von Cosinus (Reelle Zahlen) / Sinus Wellen (Imaginäre Zahlen) | ||
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+ | k => Anzahl der Zyklen. | ||
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