“decibel(symbol: dB)”的概念、定义、翻译、参考文献-科学参考

decibel(symbol: dB)

Electronics and Electrical Engineering

单词	decibel(symbol: dB)
释义	decibel(symbol: dB) Electronics and Electrical Engineering A dimensionless unit used to express the ratio of two powers, voltages, currents, or sound intensities. It is ten times the common logarithm of the power ratio. Thus if two values of power, P₁ and P₂, differ by n decibels then $n = 10 {log}_{10} (\frac{P_{2}}{P_{1}})$ i.e. $\frac{P_{2}}{P_{1}} = 10^{\frac{n}{10}}$ If P₁ and P₂ are the input and output powers, respectively, of an electric network then if n is positive, i.e. P₂>P₁, there is a gain in power; if n is negative there is a power loss. The bel (symbol: B) is equal to 10 decibels. Since it is inconveniently large the decibel is used in practice. If two power values differ by N bels then $N = {log}_{10} (\frac{P_{2}}{P_{1}})$ Compare neper.
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