a wave (as a sound wave in a chamber or an electromagnetic wave in a transmission line) in which the ratio of its instantaneous amplitude at one point to that at any other point does not vary with time

• 一种类似于室内声波或传输线的电磁波的波，其在一点的瞬时振动与另一点的顺时振动比率不随时间的变化而变化