That is, they differ in the frequencies and amplitudes of these other component vibrations or "overtones" which are going on at the same time as their fundamental vibrations.
"Letters of a Radio-Engineer to His Son"
John Mills
Notice also that the peaks have nearly identical amplitudes.
"The Egyptian Cat Mystery"
Harold Leland Goodwin
Out of the moist earth it has sprung; In the gracious amplitudes of her bosom it was nurtured, And in it is wrought the miracle of life.
"The Song of the Stone Wall"
Helen Keller