单词 | decibel |
释义 | decibel A unit used to compare two power levels, usually applied to sound or electrical signals. Although the decibel is one tenth of a bel , it is the decibel, not the bel, that is invariably used. Two power levels P and P0 differ by n decibels when n = 10log10P/P0 . If P is the level of sound intensity to be measured, P0 is a reference level, usually the intensity of a note of the same frequency at the threshold of audibility.The logarithmic scale is convenient as human audibility has a range of 1 (just audible) to 1012 (just causing pain) and one decibel, representing an increase of some 26%, is about the smallest change the ear can detect |
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