If N is odd, (8) results T([e.sup.j[omega]]) = 0 at [omega] = [pi]/2 for amplitude distortion. In order to avoid the amplitude distortion, N must be chosen even.
Figure 7 is an analytical screen showing the time domain, frequency spectrum, error vector magnitude and constellation display for a 16QAM signal with a significant level of amplitude distortion.
AM-to-PM conversion has the direct effect of leading to phase distortion even at power levels at which there is little amplitude distortion arising from gain compression.