说明：  QAM是Quadrature Amplitude Modulation的缩写，中文译名为“正交振幅调制”，其幅度和相位同时变化，属于非恒包络二维调制。QAM是正交载波调制技术与多电平振幅键控的结合 。
(QAM is Quadrature Amplitude Modulation Abbreviation, Chinese translation for " quadrature amplitude modulation" , the amplitude and phase changes at the same time, a non-dimensional constant envelope modulation. QAM is a combination of orthogonal carrier modulation technique and the multi-level amplitude shift keying.)