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Kaz
Kaz
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This is an important convention, because at the end of the signal chain, in areas such as communication or audio, voltage ultimately turns to power. Decibels are a relative power measure that comes from audio: the measure of audio level loss in long distance telephone circuits.

The bel and decibel are not intended to be ways of reducing arbitrary relative measurements to a log scale.

For instance, we don't say that a 10 kΩ resistor is 3 decibels more resistive than a 5 kΩ resistor! That would be a joke, like the one in The Art of Electronics (Horowitz and Hill):

[A] gold-plated op-amp for this application is the ultra-low-noise LT1028, which is 13 dB quieter and only 10 dB more expensive [...]

So the \$10 \log_{10}\$ scale of a relative voltage measurement may be valid in some situation, but it's just not called decibels, any more than something that costs $10 being called ten decibels more expensive than a $1 part.

This is an important convention, because at the end of the signal chain, in areas such as communication or audio, voltage ultimately turns to power. Decibels are a relative power measure that comes audio: the measure of audio level loss in long distance telephone circuits.

The bel and decibel are not intended to be ways of reducing arbitrary relative measurements to a log scale.

For instance, we don't say that a 10 kΩ resistor is 3 decibels more resistive than a 5 kΩ resistor! That would be a joke, like the one in The Art of Electronics (Horowitz and Hill):

[A] gold-plated op-amp for this application is the ultra-low-noise LT1028, which is 13 dB quieter and only 10 dB more expensive [...]

So the \$10 \log_{10}\$ scale of a relative voltage measurement may be valid in some situation, but it's just not called decibels, any more than something that costs $10 being called ten decibels more expensive than a $1 part.

This is an important convention, because at the end of the signal chain, in areas such as communication or audio, voltage ultimately turns to power. Decibels are a relative power measure that comes from audio: the measure of audio level loss in long distance telephone circuits.

The bel and decibel are not intended to be ways of reducing arbitrary relative measurements to a log scale.

For instance, we don't say that a 10 kΩ resistor is 3 decibels more resistive than a 5 kΩ resistor! That would be a joke, like the one in The Art of Electronics (Horowitz and Hill):

[A] gold-plated op-amp for this application is the ultra-low-noise LT1028, which is 13 dB quieter and only 10 dB more expensive [...]

So the \$10 \log_{10}\$ scale of a relative voltage measurement may be valid in some situation, but it's just not called decibels, any more than something that costs $10 being called ten decibels more expensive than a $1 part.

Source Link
Kaz
Kaz
  • 20.1k
  • 1
  • 41
  • 83

This is an important convention, because at the end of the signal chain, in areas such as communication or audio, voltage ultimately turns to power. Decibels are a relative power measure that comes audio: the measure of audio level loss in long distance telephone circuits.

The bel and decibel are not intended to be ways of reducing arbitrary relative measurements to a log scale.

For instance, we don't say that a 10 kΩ resistor is 3 decibels more resistive than a 5 kΩ resistor! That would be a joke, like the one in The Art of Electronics (Horowitz and Hill):

[A] gold-plated op-amp for this application is the ultra-low-noise LT1028, which is 13 dB quieter and only 10 dB more expensive [...]

So the \$10 \log_{10}\$ scale of a relative voltage measurement may be valid in some situation, but it's just not called decibels, any more than something that costs $10 being called ten decibels more expensive than a $1 part.