An effect that occurs when a signal is sampled at a rate less than twice the highest frequency present in the signal.The subsequent signal recovered from the samples will not contain the high frequency component of the original signal and will display a false low frequency signal.以低于信号中最高频率两倍的频率进行信号取样时出现的一种效应，即当由取样状态还原时，还原后的信号将不再含有原来信号中的高频成分，并将显示出虚假的低频信号。
