特形脉冲调制中射频泄漏的影响及其补偿

ARTIFACT DUE TO RF LEAKAGE IN THE MODULATION OF A SHAPED PULSE AND ITS COMPENSATION

模拟器件的非理想因素和电路分布参数等影响造成了特形脉冲调制时的射频泄漏；这些射频泄漏将对特形脉冲的激发轮廓产生缺陷．本文从特形脉冲的射频调制原理着手，分析了射频泄漏对选择激发轮廓的影响．并采用一种新的相位循环方法对它进行补偿．实验的结果表明这种补偿方法有一定的实用性．

Imperfection of analog components and influence of distributed parameters led to the rf leakage in the modulation of a shaped pulse.The rf leakage produced big artifact to the excitation profile of the shaped pulse.In this article,the artifact was analyzed on the basis of the theory of rf amplitude modulation.A new phase cycling pulse sequence was designed to reduce such kind of artifact.Experimental result showed that this phase cycling method is practical to the improvement of the feature in the selective excitation unit.