And there'd be that sound in the signal -- it's like  -- and he thought, "Oh, what if I could control that sound and turn it into an instrument, because there are pitches in it."
在信号中有这种声音——就像—— 他就想，哦，我也许可以控制这种声音 把它做成一个乐器，因为里面有不同的音高。