>From the input spectrum data (magnitude and phase), I can tell the complex input data to the inverse FFT is not "DFT Symmetric". In order to compute correct Real Inverse FFT, the input complex vector must be even symmetric on the real part and odd symetric on the imaginary part ( it is in the "DFT Symmetric" sense, please refer to any text boot regarding the FFT properties). For performance reason, the real inverse FFT will not check the symmetry of the input data. If the input data does not comply with the requirement for real inverse FFT, the result is not defined. Different Inverse FFT implementations may output different results in this case.
