The bel was originally devised by engineers of the Bell Telephone Laboratories to quantify the reduction in audio level over a 1 mile (approximately 1.6 km) length of standard telephone cable. 5.2.5 Radio power, energy, and field strength.5.1 "Absolute" and "relative" decibel measurements.
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#DECIBEL UNIT FULL#
The full name decibel follows the usual English capitalization rules for a common noun. However, following the SI convention, the d is lowercase, as it represents the SI prefix deci-, and the B is capitalized, as it is an abbreviation of a name-derived unit (the bel). It confers a number of advantages, such as the ability to conveniently represent very large or small numbers, a logarithmic scaling that roughly corresponds to the human perception of, for example, sound and light, and the ability to carry out multiplication of ratios by simple addition and subtraction. The decibel is useful for a wide variety of measurements in science and engineering (e.g., acoustics and electronics) and other disciplines. Since it expresses a ratio of two (same unit) quantities, it is a dimensionless unit. The decibel ( dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power or intensity) relative to a specified or implied reference level.
![decibel unit decibel unit](http://file2.okorder.com/prodalbum/2015/11/09/a05e21228770e1db43fb8e9808079036.jpg)
![decibel unit decibel unit](https://cdn2.iconfinder.com/data/icons/unit-of-measurement/500/measurement-unit_6-1024.png)
For other uses, see Decibel (disambiguation).