> For OFDM with many subcarriers this can get to be a very large value. It is quite likely that M_OFDM can exceed 10^50. With such high signal orders, we expect

> For OFDM with many subcarriers this can get to be a very large value. It is quite likely that M_OFDM can exceed 10^50. With such high signal orders, we expect that OFDM will not be tolerant of waveform distortion, since in OFDM, changing the waveform directly changes the data. > Comparing signal order between OFDM and QAM provides a measure of relative tolerance to waveform distortion, corresponding to linearity specifications on the receiver and transmitter circuits, particularly the PA linearity. And this directly caused high-performance headphone amplifiers.