fftshift

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The shift of the constant component to the center of the spectrum.

Library

EngeeDSP

Syntax

Function call

Y = fftshift(X) — rewrites the Fourier transform of the array X, shifting the constant component to the center of the array.
- If X — vector, then function fftshift swaps the left and right halves X.
- If X — the matrix, then the function fftshift swaps the first quadrant X with the third, and the second quadrant with the fourth.
- If X — a multidimensional array, then the function fftshift swaps half spaces X for each dimension.

Y = fftshift(X,dim) — works by dimension dim array X. For example, if X — a matrix whose rows represent several one-dimensional transformations, then fftshift(X,2) swaps the halves of each row of the matrix X.

Arguments

Input arguments

# X — input array

+ vector | matrix | multidimensional array

Details

An input array specified as a vector, matrix, or multidimensional array.

Data types	`Float64`, `Float32`, `Int8`, `Int16`, `Int32`, `Int64`, `UInt8`, `UInt16`, `UInt32`, `UInt64`, `Bool`
Support for complex numbers	Yes

# dim — the measurement by which the operation is performed

+ positive integer scalar

Details

The dimension on which the operation is performed is specified as a positive integer. If the value is not specified, then the function fftshift swaps all dimensions.

Consider the input matrix Xc. Operation fftshift(Xc,1) swaps the halves of each column of the matrix Xc.
Consider the matrix Xr. Operation fftshift(Xr,2) swaps the halves of each row of the matrix Xr.

Data types

Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64

Output arguments

# Y — output array

Details

The output array returned as a vector, matrix, or multidimensional array.