gsignal (version 0.3-7)

ifftshift: Inverse zero-frequency shift

Description

Rearranges a zero-frequency-shifted Fourier transform back to the original.

Usage

ifftshift(x, MARGIN = 2)

Value

back-transformed vector or matrix.

Arguments

x

input data, specified as a vector or matrix.

MARGIN

dimension to operate along, 1 = row, 2 = columns (default). Specifying MARGIN = c(1, 2) centers along both rows and columns. Ignored when x is a vector.

Author

Vincent Cautaerts, ,
adapted by John W. Eaton.
Conversion to R by Geert van Boxtel, .

Details

Undo the action of the fftshift function. For even length x, fftshift is its own inverse, but not for odd length input.

See Also

fftshift

Examples

Xeven <- 1:6
res <- fftshift(fftshift(Xeven))

Xodd <- 1:7
res <- fftshift(fftshift(Xodd))
res <- ifftshift(fftshift(Xodd))