The following Matlab project contains the source code and Matlab examples used for fft split split the fft of two real sequences.
function [X1 X2] = fft_split(X)
x = x1 + 1i*x2;
X = fft(x);
X1 = fft(x1);
X2 = fft(x2);
This operation is useful when the FFTs of two real-valued sequences have to be computed at the same time, on a platform with limited resources, for example a small DSP or FPGA.