white noise
noun /ˌwaɪt ˈnɔɪz/
  /ˌwaɪt ˈnɔɪz/
 [uncountable] (physics- noise that contains many different sound frequencies that are equally strong, for example the noise that comes from a television or radio that is turned on but not tuned in白噪声(整个频道范围内的噪声)