% priama X(k) z x(n)
function X = DFT_priama(x)
  N = length(x);
  X = zeros(1,N);
  for k = 0:(N - 1)
    Xk = 0;
    for n = 0:(N - 1)
      Xk = Xk + ( x(n + 1) .* exp(-1j * 2 * pi * n * k / N) );
    end
    X(k + 1) =  Xk;
  end
  X = 1/N * X;
end