The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 1/10 (approximately 1.26) or root-power ratio of 10 1/20 (approximately 1.12). [1][2]

2023年2月24日 · dB 分贝（工程应用），dB（Decibel，分贝）是一个纯计数单位，本意是表示两个量的比值大小，没有单位。 在工程应用中经常看到貌似不同的定义方式（仅仅是看上去不同）。 对于电压或电流：dB = 20*lg (A/B)。 此处 A，B 代表参与比较的功率值或者电流、电压值。 dB 的意义其实再简单不过了，就是把一个很大（后面跟一长串 0 的）或者很小（前面有一长串 0 的）的数比较简短地表示出来。 如（此处以功率为例）： X = 100000 = 10^5； X (dB) = 10*lg (X) …

The bel F.1 is an amplitude unit defined for sound as the log (base 10) of the intensity relative to some reference intensity, F.2 i.e., The choice of reference intensity (or power) defines the particular choice of dB scale. Signal intensity, power, and energy are always proportional to the square of the signal amplitude. Thus, we can always ...

db与log之间公式有：dB = 10log （P1/P2）= 20 log （V1 / V2）（P代表功率，V代表电压）。 V1是测试数据，V2是参考标准。 例如 V1数据是 V2的2倍，就是6 dB。

通过这种方法，log函数可以同时显示小数域和大数域的细节。 所以，在许多情况下，我们用分贝标度来表示一个比率。 dB = 10Log10（P/Reference） 根据它所代表的比率，我们用各种下标来表示dB，如下所示。如：dBm、 dBc 、 dBi 等。

This appendix provides an introduction to logarithms (real and complex) and decibels, a quantitative measure of sound intensity. Several specific dB scales are defined, and dynamic range considerations in audio are considered.

The decibel (dB) uses a logarithmic scale to draw a comparison between two quantities like Power, Voltage, current, or intensity. This unit is commonly used in the fields of signal processing, audio engineering, telecommunications, and electronics.

2006年10月3日 · X_dB = 10log_10 (X/X0) This way, if X is 10 times X0, we read X is 10dB greater than X0. On the usefulness of utilizing the log_10: it allows to express a very large range of ratios in a range of moderate size, allowing one to …

When calculating decibels, we use the common logarithm, written as log, with its base value of 10.

The NoiseMeters decibel calculator can be used to carry out addition and subtraction of dB values between 0 and 200 dB. Sound levels are generally expressed in decibels, which are logarithmic and so cannot be manipulated without being converted back to a linear scale.