[Sound of dentist drill.] That's a sound that inspires fear around the world: the dentists' drill. And fear of that sound itself could play a part in keeping some people from getting their regularly-scheduled check-up. Now, ____1____ this "sound effect" may ____2____. Because researchers in London have developed technology to ____3____ the drill's unpleasant high-pitched whine.
Noise cancelling headphones usually do away with low pitches. So the scientists designed a variation that a dentist could keep on hand. The device fits between any MP3 player or mobile phone and the patient's own headphones. The patients could still hear the dentist or listen to their own music. But the microphone and chip in the device sample the incoming sound and produce an ____4____ wave that ____5____ just the sound of the drill. As the drill's frequency changes, the waveform quickly adapts to maintain the silence.
The researchers have built and tested a prototype. They hope that it could eventually finally provide a ____6____ answer to the question, "Is it safe?"
【视听版科学小组荣誉出品】
a solution to be in sight cancel out inverted cancels out definitive
新设备消除牙钻声和病人的恐惧 （牙钻声）牙医手中牙钻的声音恐怕会激起全世界人的恐惧。而某些人会由于对这种声音的恐惧而不去做定期对牙科检查。现在，对付这种“声效”的解决方法或许就在眼前。伦敦的科学家们开发了一种技术来抵消牙钻发出的令人不快的尖锐刺耳的噪鸣声。 降噪耳机通常都能排除低频噪音。据此，科学家们设计了一首牙科医生应常备在手的变奏曲。这种设备可与任何MP3播放器或手机及病人自己的耳机配合使用。而病人仍然可以听到牙医说话或聆听自己选好的音乐。不过，该设备上内置的麦克风和芯片会对传入的声音取样并制造反相波，这种反相波刚好可以抵消牙钻的声音。当牙钻的音频发生变化，设备制造的波形会迅速调适，保持安静。 研究人员制造出了一个设备原型，加以测试。他们希望这个设备最终能为一个问题提供明确可靠的答案，这个问题就是：“它安全吗？”