From d97df53d72f66db206da540e909679fa863b51b6 Mon Sep 17 00:00:00 2001 From: Abhinav Dronamraju Date: Wed, 29 Nov 2017 17:34:00 +0530 Subject: Added xml files and new functions --- help/en_US/fftshift1.xml | 64 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 help/en_US/fftshift1.xml (limited to 'help/en_US/fftshift1.xml') diff --git a/help/en_US/fftshift1.xml b/help/en_US/fftshift1.xml new file mode 100644 index 0000000..8ce7eab --- /dev/null +++ b/help/en_US/fftshift1.xml @@ -0,0 +1,64 @@ + + + + + + + + fftshift1 + Perform a shift of the vector X, for use with the 'fft' and 'ifft' functions, in order the move the frequency 0 to the center of the vector or matrix. + + + + + Calling Sequence + + fftshift1 (X) + fftshift1 (X, DIM) + + + + + Parameters + + X: + It is a vector of N elements corresponding to time samples + DIM: + The optional DIM argument can be used to limit the dimension along which the permutation occurs + + + + + Description + +This is an Octave function. +Perform a shift of the vector X, for use with the 'fft' and 'ifft' functions, in order the move the frequency 0 to the center of the vector or matrix. + + +If X is a vector of N elements corresponding to N time samples spaced by dt, then 'fftshift1 (fft (X))' corresponds to frequencies + + +f = [ -(ceil((N-1)/2):-1:1)*df 0 (1:floor((N-1)/2))*df ] + + +where df = 1 / dt. + + +If X is a matrix, the same holds for rows and columns. If X is an array, then the same holds along each dimension. + + +The optional DIM argument can be used to limit the dimension along + + + -- cgit