[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?"
【視聽(tīng)版科學(xué)小組榮譽(yù)出品】
a solution to be in sight cancel out inverted cancels out definitive
新設(shè)備消除牙鉆聲和病人的恐懼 （牙鉆聲）牙醫(yī)手中牙鉆的聲音恐怕會(huì)激起全世界人的恐懼。而某些人會(huì)由于對(duì)這種聲音的恐懼而不去做定期對(duì)牙科檢查?，F(xiàn)在，對(duì)付這種“聲效”的解決方法或許就在眼前。倫敦的科學(xué)家們開(kāi)發(fā)了一種技術(shù)來(lái)抵消牙鉆發(fā)出的令人不快的尖銳刺耳的噪鳴聲。 降噪耳機(jī)通常都能排除低頻噪音。據(jù)此，科學(xué)家們?cè)O(shè)計(jì)了一首牙科醫(yī)生應(yīng)常備在手的變奏曲。這種設(shè)備可與任何MP3播放器或手機(jī)及病人自己的耳機(jī)配合使用。而病人仍然可以聽(tīng)到牙醫(yī)說(shuō)話或聆聽(tīng)自己選好的音樂(lè)。不過(guò)，該設(shè)備上內(nèi)置的麥克風(fēng)和芯片會(huì)對(duì)傳入的聲音取樣并制造反相波，這種反相波剛好可以抵消牙鉆的聲音。當(dāng)牙鉆的音頻發(fā)生變化，設(shè)備制造的波形會(huì)迅速調(diào)適，保持安靜。 研究人員制造出了一個(gè)設(shè)備原型，加以測(cè)試。他們希望這個(gè)設(shè)備最終能為一個(gè)問(wèn)題提供明確可靠的答案，這個(gè)問(wèn)題就是：“它安全嗎？”