decibels above reference noise [`des·ǝ·bǝlz ǝ¦bǝv `ref·rǝns ´nȯiz] ELECTRICITY Units used to show the relationship between the interfering effect of a noise frequency, or band of noise frequencies, and a fixed amount of noise power commonly called reference noise; a 1000-hertz tone having a power level of -90 dBm was selected as the reference noise power; superseded by the adjusted decibel unit. Abbreviated dBrn. |