The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded on a seismogram at a certain period.
地震级别是根据某一时期震动图记录的地震波振幅的对数值计算的。
It is called delta sleep because of the presence of high amplitude, low frequency delta waves that are seen to occur in the EEG.
这个阶段的脑电图以高幅低频的三角形delta波为主，所以被称为Delta睡眠。
The spectral analysis technique works well for waves of varying amplitude, too.
频谱分析法对幅度变化的波形也有效。
应用推荐