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bencholmes/forceFFTSymmetry.m

Created August 30, 2018 13:30
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A MATLAB function to force symmetry on an FFT, thus producing a real signal after an IFFT.
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forceFFTSymmetry.m
function X = forceFFTSymmetry(X)
% forceFFTSymmetry A function to force conjugate symmetry on an FFT such that when an
% IFFT is performed the result is a real signal.
% The function has been written to replace MATLAB's ifft(X,'symmetric'), as this function
% is not compatible with MATLAB Coder.
% Licensed under Creative Commons Zero (CC0) so use freely.
XStartFlipped = fliplr(X(2:floor(end/2)));
X(ceil(end/2)+2:end) = real(XStartFlipped) - sqrt(complex(-1))*imag(XStartFlipped);
% Or
% X(ceil(end/2)+2:end) = conj(XStartFlipped);
end
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