MATLAB FFT

you can run :

x = [0 1 4 9];
N = length(x);
W = exp(-1i * 2 * pi / N);
X = zeros(1, N);

for k = 0:(N - 1)
  for n = 0:(N - 1)
    X(k + 1) = X(k + 1) + x(n + 1) * W^(k * n);
  end
end

this is used as a function via fftp1.m

function X=fftp1(x)
%x = [0 1 4 9];
N = length(x);
W = exp(-1i * 2 * pi / N);
X = zeros(1, N);

for k = 0:(N - 1)
  for n = 0:(N - 1)
    X(k + 1) = X(k + 1) + x(n + 1) * W^(k * n);
  end
end
end

更正

請以以下CODE為主

https://github.com/andythebreaker/GSM-Image-Transfer-Using-FFT/blob/master/fftp3.m

the math behind it is:

file1	file2
files-1685257200970.zip	files-1685257202072.zip