本身不取任意值，只能取某些规定值的离散信号digital signal

• 海尔脑力波电视将脑电波转化成数字信号控制电视。

  Haier's Brain Wave TV turns brain waves into digital signals to control the television.

• 一市三县的10万户家庭都配备无线数字信号接收机顶盒。

  100,000 households in three counties and one city are equipped with wireless digital signal receiver set-top boxes.