fft

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MagicPlot uses 'electrical engineering' convention to set the sign of the exponential phase factor of FFT as follows from the table below. ^{1)}

Normalize Forward Transform | Forward Transform (Signal→Spectrum) | Inverse Transform (Spectrum→Signal) |
---|---|---|

Unchecked | ||

Checked |

Here are complex signal components and are complex spectrum components, .

Center Zero Frequency | Sampling Column Values |
---|---|

Unchecked | |

Checked |

Here is given sampling interval of initial data.

Sampling Interval | Sampling interval is used to compute the data in resulting sampling column. If `Get from` box is set, MagicPlot will calculate sampling interval as difference between two beginning values from given column. You can set sampling interval manually by checking `Set manually` box. |
---|---|

Real Imaginary | Columns with real and imaginary components of data. If your data is only real, select `<all zeros>` imaginary item |

Forward Inverse | Transform direction |

Normalize forward transform | Divide forward transform result by number of points N |

Center zero frequency | If selected, after forward Fourier transform the two parts of spectrum will be rearranged so that the lower frequency components are in the center; the opposite rearrangement of spectrum will be done before inverse transform if any. |

Most scientific applications uses the same sign conventions. But note, that the sign of exponential phase factor in Numerical Receipts in C, 2nd edition, p. 503 is the opposite

fft.1272233700.txt.gz · Last modified: Sun Nov 8 12:20:32 2015 (external edit)

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