单词 | noise |
释义 | noise 1 Any undesired sound. It is measured on a decibel scale ranging from the threshold of hearing (0 dB) to the threshold of pain (130 dB). Between these limits a whisper registers about 20 dB, heavy urban traffic about 90 dB, and a heavy hammer on steel plate about 110 dB. A high noise level (industrial or from overamplified music, for example) can cause permanent hearing impairment. 2 Any unwanted disturbance within a useful frequency band in a communication channel. ![]() Noise: decibel scale |
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