单词 | perceived noise decibel |
释义 | > as lemmasperceived noise decibel perceived noise n. Acoustics noise as measured by comparison to the sound pressure level of a reference sound which independent observers assess to be of the same volume; usually attributive, esp. in perceived noise decibel (abbreviated PNdB), perceived noise level. ΚΠ 1959 K. D. Kryter in Jrnl. Acoustical Soc. Amer. 31 1424/1 The following..steps were taken in arriving at the procedure suggested for the calculation of the perceived noise kind of a sound [etc.]. 1959 K. D. Kryter in Jrnl. Acoustical Soc. Amer. 31 1425/1 By definition, the perceived noise level of sound ‘X’ (in PNdb) is the sound pressure level in db re 0·0002 μbar of the 910–1090 cps band of random noise that is judged by an average listener to be acceptable (or, inversely, as unacceptable). 1971 Nature 19 Feb. 518/1 Mr Stein's apparently innocent bill to limit noise at New York airports to 108 perceived noise decibels by July..could be..a serious threat to the viability of Concorde. 2002 Noise Regulation Rep. (Nexis) Sept. 95 NASA's Goals and Objectives for the Aerospace Technology Enterprise aims to reduced perceived noise of new aircraft by 75 percent in 25 years. < as lemmas |
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