User talk:Boute/Decibel draft

Boute, you have made an excellent start here (I hope you don't mind me correcting what I assume was a typo). I notice that you do not mention the use of the decibel for field quantities. I have never understood the line taken by the IEC on the distinction between power and field quantities so am curious to see what you plan to include - perhaps the field quantities will make an appearance when you introduce the neper. Anyway, while you seem to have everything under control, I would be pleaed to help if I can - let me know, either here or on my talk page. Dondervogel 2 (talk) 19:54, 13 March 2011 (UTC)[reply]

Thank you for your encouragement. You rightly corrected a typo. The topics in which you expressed interest are covered in the second part of the draft, now complete and added to the first part. The "field quantities" are renamed "root-power quantities" as prescribed in Annex C of ISO 80000-1:2009. Boute (talk) 15:29, 14 March 2011 (UTC)[reply]

I also appreciate your offer to help, which I gladly accept. Could you provide references to the papers by Horton and more recent publications you have in mind that can be used as references for criticism of the sloppy conventions around the decibel? You can put them here or on Talk:Decibel to keep decibel-related material together. Boute (talk) 09:20, 16 March 2011 (UTC)[reply]

confusion and the decibel: some references[edit]

Here are some relevant refs to start with

C S Clay, Underwater sound transmission and SI units, J Acoust Soc Am 106, 3047 (1999).
R Hickling, Noise control and SI units, J Acoust Soc Am 106, 3048 (1999).
D M F Chapman, Decibels, SI units, and standards, J Acoust Soc Am 108, 480 (2000).
D M F Chapman & D D Ellis, The elusive decibel: thoughts on sonars and marine mammals, Acoust Canadienne 26(2), 29-31 (1998).

These ones are relatively recent. The older material, some of which is referred to by Hickling 1999, will take more digging. Dondervogel 2 (talk) 10:35, 16 March 2011 (UTC)[reply]

Afterthought: this search partly duplicates the above list, but there are some new ones as well. Dondervogel 2 (talk) 10:42, 16 March 2011 (UTC)[reply]

... and here are the older ones, both by Horton

J W Horton, The bewildering decibel, Electrical Engineering, 73(6), 550-555 (1954).
J W Horton, Fundamental considerations regarding the use of relative magnitudes, Proc Inst of Radio Engineers, 40 (4), 440-444 (1952).

Dondervogel 2 (talk) 11:10, 17 March 2011 (UTC)[reply]

Interesting references. I could not find a copy of J W Horton, "The bewildering decibel", but Googling shows it is referenced in a recent report Richard A Katz et al., The Decibel Report. Downloading this report succeeded only in HTML (which clobbers formulas), but reveals interesting viewpoints w.r.t. Horton, illustrating the danger of utter confusion. Boute (talk) 17:24, 17 March 2011 (UTC)[reply]

Katz: You are not missing much, but try this.
Horton: His 1954 abstract reads 'The term "decibel" has been used for quantities for which it is not the assigned designation. Confusion and error have resulted. To restore precision and stability to our technical terminology, it is recommended that this term be assigned specifically to unit transmission loss and that the word "logit" be used for standard magnitudes which combine by multiplication. Thus logit would serve as a companion to the word "unit" now used for standard magnitudes which combine by addition'

Horton also defined the decibel once. I don't remember where just now but will look through my records. Dondervogel 2 (talk) 07:05, 18 March 2011 (UTC)[reply]

Another relevant quote, from J Valdes, The unit one, the neper, the bel and the future of the SI, metrologia 2002, 39, 543-549: "when we measure pressures relative to the [pascal] and pressure "levels" in decibels relative to 20 uPa ... a confusing situation arises similar to the adoption of two different units for quantities of the same kind. Even experts in acoustics in acoustical terminology recognize that the consequences of a decibel scale are confusing and that decibel representations can be avoided simply by converting all levels to the underlying physical quantities". Dondervogel 2 (talk) 02:13, 11 June 2012 (UTC)[reply]

Horton's definition[edit]

I found Horton's definition, which turns out not to be completely original. The text (from Horton 1959) reads, verbatim "The decibel, as originally defined, and as it will be used in this book, is that unit transmission loss for which the ratio of the reduced rate of energy flow to the unreduced rate of energy flow is 10^-0.1." The words "as originally defined" point to Martin 1929, which I don't appear to have in my collection. I will request a copy.

W H Martin, Decibel - the name for the Transmission Unit Bell System Technical Journal, New York, 8(1), January 1929, p1.
J. W. Horton, Fundamentals of SONAR, second edition (United States Naval Institute, Annapolis, 1959).

Dondervogel 2 (talk) 08:46, 21 March 2011 (UTC)[reply]

I tried to find the original 1924 and 1929 papers by Martin by Googling BSTJ and discovered the complete BSTJ collection on the Alcatel-Lucent BSTJ site. A real treasure trove! Boute (talk) 14:27, 22 March 2011 (UTC)[reply]

Thanks for this tip. Amazing! Martin 1929 basically defines the decibel (symbol db) as "one transmission unit", which takes us back to Hartley 1924. Hartley's Elec Comms paper gives a long-winded explanation of the nature and intended use of the "transmission unit". At one point it even quotes a numerical value, of log10^0.1, but a quick scan failed to reveal a definition anywhere. Can you see one? Dondervogel 2 (talk) 18:30, 22 March 2011 (UTC)[reply]

10/20 log and base multiplier confusion discussed again[edit]

The issue on 10log or 20log and 10^x multiplier is discussed again. I have seen you have done some work on this. Maybe it would interest you? see "Talk:Decibel##Base 10^x and y*log10 multipliers are missing in the article!". Electron9 (talk) 11:38, 10 June 2012 (UTC)[reply]