18.4.1.1 The FFT Dialog BoxFFT1Dialog
 Menu Command: Analysis: Signal Processing: FFT: FFT
 Window Types: Workbook, Graph
 XFunction Script and GUI Examples: fft1
Common Controls
Input tab
Input

Specifies the input signal, which could be complex. The real and imaginary parts of the signal can be saved in different columns or in the same column. The default is <Active>, which corresponds to the active dataset.
See Specifying Your Input Data.

Options tab
Sampling Interval

Specifies the sampling interval. The default is <Auto>, which corresponds to an automaticallycomputed interval. Please see the algorithm section for details.

Window

Specifies the type of window used to suppress frequency leakage.
 Rectangle
 Welch
 Triangular
 Bartlett
 Hanning
 Hamming
 Blackman
For more information, see Algorithms, FFT

Window Correction

Specifies the Window Correction Factor used to correct the alteration made by applying a window to the input data.
 None: No correction is applied.
 Amplitude: Amplitude Correction is applied. It is used when the true amplitude of narrow band data is required. The Amplitude Correction Factor is defined as
 Power: Energy Correction is applied. It is used when the true energy level of the data is required. The Power Correction Factor is defined as

Normalize Re, Im, and Mag

Specifies whether to normalize the complex, real, imaginary, magnitude, and square magnitude output. The default is false. Note that other outputs such as amplitude are not affected by this variable. Please see the algorithm section for details.

Shift

Specifies whether the result should be rearranged so that the lower frequency components are in the center.

Unwrap phase

Specifies whether the phase should be unwrapped.

Factor

Specifies whether the Electrical Engineering or Science convention is used to set the sign of the Exponential Phase factor.
 1 (Electrical Engineering): The phase factor sign will be opposite to that of the Science option.
 +1 (Science): The phase factor will be set according to the formulae listed on page 503 of Numerical Recipes in C, 2nd edition.

Spectrum Type

Specifies the Nyquist interval over which power is calculated.
 <auto>: If the input signal is real, onesided power will be chosen; otherwise, twosided power will be selected. When this option is selected, Origin will look at the input data to determine whether it is complex or not. If the input data is stored in a column of the Complex data type, but the data contains only a real part, Origin will regard it as real, and not as complex, resulting in a onesided spectrum. Alternately, if the input data has an allzero column as the imaginary part, Origin will also regard the input as real, and produce a onesided spectrum.
 Onesided: Onesided power will be computed.
 Twosided: Twosided power will be computed.

Normalize power to

Specifies the power density normalization method. Please see the algorithm section for details.
 MSAMean Square Amplitude: Mean square amplitude method.
 SSASum Square Amplitude: Sum square amplitude method.
 TISATime Interval Square Amplitude': Time Integral square amplitude method.

Preview

Specifies the preview content in the dialog.
None, Amplitude/Phase, Power/Phase, Amplitude, Imaginary, Magnitude, Phase, Power, Real, Real/Imaginary, dB, Normalized dB, RMS Amplitude, Square Amplitude , Square Magnitude

Plot tab
Select check boxes to create output of the following components of the FFT results:
Real, Imag, Amplitude/Phase, Phase, Power/Phase, Real/Imag, Magnitude, Amplitude, Power, dB, Normalized dB, RMS Amplitude, Square Amplitude, Square Magnitude.
Output tab
See Output Results.
Result Data Sheet

Specifies the worksheet sheet for outputting the result data.

Result Graph Sheet

Specifies the sheet for outputting the result graphs.

