| 单词 | pndb |
| 释义 | > as lemmasPNdB PNdB n. (also PNDB, PNdb) perceived noise decibel(s). ΘΚΠ the world > matter > physics > science of sound > [noun] > unit of sound decibel1928 phon1932 phonon1932 PNdB1959 db.1975 1959 K. D. Kryter in Jrnl. Acoustical Soc. Amer. 31 1425/1 The translation from perceived noisiness in noys to perceived noise level in PNdb is expressed by the equation PNdb = (1.2 t log10N)/0.03, where N is the number of noys. 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) as sound ‘X’, under specified conditions of listening and testing. 1998 Newsday (Nexis) 22 Jan. a37 A decibel reading of 112 PNDB (perceived noise decibels) triggers an aircraft violation. < as lemmas |
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