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Description
This command allows Fourier Transform operations on components of an existing dataset. Users can choose to operate on the original data, the complex or real parts of the data, or view the various field components separately.
Navigation
This command can be accessed by right mouse clicking in the main chart view and selecting "Fourier Transform (FFT)" from the list menu.
Controls
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Control
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Inputs / Description
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Defaults
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Operation
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No operation
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Will not perform a Fourier Transform. This allows selection of the Data Form to View options without making an FFT calculation.
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Not Selected
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Fourier Transform
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Perform a Fourier Transform
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Selected
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Inverse Fourier Transform
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Perform an Inverse Fourier Transform
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Not Selected
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X-axis Label
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Specifies label to be placed on the X-axis
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X Frequency
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Y-axis Label
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Specifies label to be placed on the Y-axis
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Y Frequency
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Z-axis Label
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Specifies label to be placed on the Z-axis
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FFT
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Data Form to View
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Magnitude
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Displays |z| ( z = x + iy )
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Selected
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Magnitude Squared
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Displays |z|2
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Not Selected
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Signed Magnitude
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Displays signed |z|
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Not Selected
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Phase
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Displays Atan( y/x )
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Not Selected
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Real
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Displays x
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Not Selected
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Imaginary
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Displays y
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Not Selected
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Dataset to Transform
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Original data (real)
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Transforms original dataset
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Not Selected
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Current data (complex)
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Transforms the complex part of the dataset
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Selected
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Current view data (real)
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Transforms the real part of the dataset
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Not Selected
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OK
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Accept settings and close dialog box
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Cancel
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Discard settings and close dialog box
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Apply
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Apply settings and keep dialog box open
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Help
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Access this Help page
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Application Notes
Size of the Fourier Transform Grid
The Fourier Transform grid must have 2n x 2n pixels (i.e. 16, 32, 64...). FRED will automatically size the transform grid to meet this requirement such that the transform grid is the smallest grid possible such that Nf is greater than or equal to Nx, where Nf is the number of pixels in the transform grid and Nx is the number of pixels in the analysis surface. Consider the following examples:
•If Nx = 127, then FRED makes Nf = 128
•If Nx = 128, then FRED makes Nf = 128
•If Nx = 129, then FRED makes Nf = 256
Related Topics
Example - MTF Calculation in FRED
Chart Viewer Controls
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Copyright © Photon Engineering, LLC
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