中文摘要：

四级核回波实验通常需要射频脉冲能够激发谱宽超过100 kHz的信号。在最近的研究中，作者发现组合脉冲COM-II （901809013545）能够在氘核的四级核回波实验中实现宽带激发。此外，作者还结合了八步相位循环的方法，有效消除了由有限脉宽效应造成的谱图扭曲现象。利用了平均哈密顿原理，对该方法进行了理论计算研究。作者采用了自旋为1的矩阵算符，通过计算解释了八步相位循环能够消除谱图扭曲的原因。

英文摘要：

Quadrupolar echo NMR spectroscopy of solids often requires RF pulse excitation that covers spectral widths exceeding 100 kHz. In a recent work we found out that a composite pulse COM-II（901809013545）,provided robust broadband excitation for deuterium quadrupolar echo spectroscopy. Moreover, when combined with an 8-step phase cycle, spectral distortions arising from finite pulse widths were greatly suppressed. In this paper we report on a theoretical analysis of COM-II with 8-step phase cycle by average Hamiltonian theory. This treatment is combined with the fictitious spin-1 operator formalism, and the mechanism of the 8-step phase cycling that minimizes the spectral distortions is discussed.