FFT VI

Owning Palette: Transforms VIs

Requires: Multicore Analysis and Sparse Matrix Toolkit

Computes the fast Fourier transform (FFT) of the input sequence X.

Wire data to the X input to determine the polymorphic instance to use or manually select the instance.

Details  

1D FFT (DBL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT size specifies the length of the FFT you want to perform. If FFT size is greater than the number of elements in X, this VI adds zeros to the end of X to match the size of FFT size. If FFT size is less than the number of elements in X, this VI uses only the first n elements in X to perform the FFT, where n is the FFT size. If FFT size is less than or equal to zero, this VI uses the length of X as the FFT size.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

1D FFT (SGL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT size specifies the length of the FFT you want to perform. If FFT size is greater than the number of elements in X, this VI adds zeros to the end of X to match the size of FFT size. If FFT size is less than the number of elements in X, this VI uses only the first n elements in X to perform the FFT, where n is the FFT size. If FFT size is less than or equal to zero, this VI uses the length of X as the FFT size.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

1D FFT (CDB)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT size specifies the length of the FFT you want to perform. If FFT size is greater than the number of elements in X, this VI adds zeros to the end of X to match the size of FFT size. If FFT size is less than the number of elements in X, this VI uses only the first n elements in X to perform the FFT, where n is the FFT size. If FFT size is less than or equal to zero, this VI uses the length of X as the FFT size.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

1D FFT (CSG)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT size specifies the length of the FFT you want to perform. If FFT size is greater than the number of elements in X, this VI adds zeros to the end of X to match the size of FFT size. If FFT size is less than the number of elements in X, this VI uses only the first n elements in X to perform the FFT, where n is the FFT size. If FFT size is less than or equal to zero, this VI uses the length of X as the FFT size.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

2D FFT (DBL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

2D FFT (SGL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

2D FFT (CDB)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

2D FFT (CSG)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 2D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

3D FFT (DBL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	Xspecifies the input sequence.
	FFT rows specifies the number of rows of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT pages specifies the number of pages of the 3D FFT. This VI truncates or zero pads X to an m-by-n-by-k array before performing the FFT, where m is FFT rows, n is FFT columns, and k is FFT pages.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

3D FFT (SGL)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT pages specifies the number of pages of the 3D FFT. This VI truncates or zero pads X to an m-by-n-by-k array before performing the FFT, where m is FFT rows, n is FFT columns, and k is FFT pages.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

3D FFT (CDB)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT pages specifies the number of pages of the 3D FFT. This VI truncates or zero pads X to an m-by-n-by-k array before performing the FFT, where m is FFT rows, n is FFT columns, and k is FFT pages.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

3D FFT (CSG)

	shift? specifies whether this VI shifts the DC component to the center of FFT {X}. The default is FALSE.
	X specifies the input sequence.
	FFT rows specifies the number of rows of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT columns specifies the number of columns of the 3D FFT. This VI truncates or zero pads X to an m-by-n array before performing the FFT, where m is FFT rows and n is FFT columns.
	FFT pages specifies the number of pages of the 3D FFT. This VI truncates or zero pads X to an m-by-n-by-k array before performing the FFT, where m is FFT rows, n is FFT columns, and k is FFT pages.
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	FFT {X} returns the FFT of X.
	error out contains error information. This output provides standard error out functionality.

FFT Details

The following table lists the support characteristics of this VI.

Supported on RT targets	Yes
Suitable for bounded execution times on RT	Yes

Refer to the Details section in the FFT VI for more details about the 1D and 2D instances of this VI.

3D FFT

For 3D signals, this VI computes the discrete Fourier transform (DFT) of the input 3D array. The following equation defines the DFT of an M-by-N-by-K array:

for u = 0, 1, … M–1; v=0, 1, …, N–1; w=0, 1, …, K–1.

where X is the input signal and Y is the transform result.