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All the sources claiming that the value in nepers is are also saying that in decibels it is which is patently incorrect, decibels are clearly defined such that it is - assuming the ratio between decibels and nepers are correct it is as given in [1] [2] and [3]
http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm gives a clue as to where the 20 came from, but it needs to be made clear that the version with 20 and without 1/2 is specifically for power ratios in terms of values given in terms of voltage or current, rather than for power ratios in terms of power or ratios of any other quantity given in terms of that quantity.
It looks like is supposed to be where is a quantity that varies as the square of the quantity whose ratio is being considered in nepers.
-- Random832 ( contribs) 17:54, 28 April 2008 (UTC)
I've added a citation needed for 1 Np = 1. I can't find a source for this after a few minutes' Google searching. I haven't paid for the ISO document. To me, it would make more sense if 0 Np = 1. -- Doradus ( talk) 11:51, 25 August 2016 (UTC)
The statement LA = n Np (where n is a number) is interpreted to mean that ln(A2/A1) = n. Thus when LA = 1 Np, A2/A1 = e. The symbol A is used here to denote the amplitude of a sinusoidal signal, and LA is then called the neperian logarithmic amplitude ratio, or the neperian amplitude level difference.
I note with interest that the Draft of the ninth SI Brochure says:
This borders on being incompatible with this article and Level (logarithmic quantity) (and the ISO 80000-3 standard). Are there substantial examples (outside of a few standards and articles about them) where the Np is used in the sense of loge2 (as opposed to loge)? I know usage of dB for both 10 log10 and 20 log10 is extensive (unfortunately). — Quondum 03:35, 13 November 2018 (UTC)
The initial equations in this article need repair. The Neper is defined as natural log of a ratio of powers. One can take the log of a dimensionless number. One can take the log of the ratio of two powers because that is dimensionless. One cannot equate the log of the ratio of two powers to the difference of the log of the numerator and log of the denominator, since these have dimensions and the log function argument must be dimensionless. Tedweverka ( talk) 18:29, 25 October 2022 (UTC)
If it means "The level of a ratio", then what is "The level of a ratio"?
In my understanding "Neper" and "dB" are ratios
and you only have to write a small number because the number is interpreted differently.
Somehow the whole notation of writing
seems wrong to me. Because,...
then one could conclude,
and then,... is there a Rule that prevents me,...
Shouldn't it be notated like so ?
This
level-5 vital article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||
|
All the sources claiming that the value in nepers is are also saying that in decibels it is which is patently incorrect, decibels are clearly defined such that it is - assuming the ratio between decibels and nepers are correct it is as given in [1] [2] and [3]
http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm gives a clue as to where the 20 came from, but it needs to be made clear that the version with 20 and without 1/2 is specifically for power ratios in terms of values given in terms of voltage or current, rather than for power ratios in terms of power or ratios of any other quantity given in terms of that quantity.
It looks like is supposed to be where is a quantity that varies as the square of the quantity whose ratio is being considered in nepers.
-- Random832 ( contribs) 17:54, 28 April 2008 (UTC)
I've added a citation needed for 1 Np = 1. I can't find a source for this after a few minutes' Google searching. I haven't paid for the ISO document. To me, it would make more sense if 0 Np = 1. -- Doradus ( talk) 11:51, 25 August 2016 (UTC)
The statement LA = n Np (where n is a number) is interpreted to mean that ln(A2/A1) = n. Thus when LA = 1 Np, A2/A1 = e. The symbol A is used here to denote the amplitude of a sinusoidal signal, and LA is then called the neperian logarithmic amplitude ratio, or the neperian amplitude level difference.
I note with interest that the Draft of the ninth SI Brochure says:
This borders on being incompatible with this article and Level (logarithmic quantity) (and the ISO 80000-3 standard). Are there substantial examples (outside of a few standards and articles about them) where the Np is used in the sense of loge2 (as opposed to loge)? I know usage of dB for both 10 log10 and 20 log10 is extensive (unfortunately). — Quondum 03:35, 13 November 2018 (UTC)
The initial equations in this article need repair. The Neper is defined as natural log of a ratio of powers. One can take the log of a dimensionless number. One can take the log of the ratio of two powers because that is dimensionless. One cannot equate the log of the ratio of two powers to the difference of the log of the numerator and log of the denominator, since these have dimensions and the log function argument must be dimensionless. Tedweverka ( talk) 18:29, 25 October 2022 (UTC)
If it means "The level of a ratio", then what is "The level of a ratio"?
In my understanding "Neper" and "dB" are ratios
and you only have to write a small number because the number is interpreted differently.
Somehow the whole notation of writing
seems wrong to me. Because,...
then one could conclude,
and then,... is there a Rule that prevents me,...
Shouldn't it be notated like so ?