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Main article: "Level (logarithmic quantity)

According to Annex A, "[t]he logarithm of the ratio of a quantity, Q, and a reference value of that quantity, Q0, is called a level". For example LP = "ln(P/P0) is the "level of a power quantity P.

Annex B (normative) – "Rounding of numbers[edit]

Annex C (normative) – Logarithmic quantities and their units[edit]

Field, power, and root-power quantities

Annex C introduces the concepts of power quantities and root-power quantities, and deprecates field quantity.

Annex D (informative) – International organizations in the field of quantities and units[edit]


  1. ^ "ISO 80000-1:2009". "International Organization for Standardization. Retrieved 20 July 2013. 
  2. ^ http://www.iso.org/iso/catalogue_detail?csnumber=30669
  3. ^ http://www.bipm.org/en/CGPM/db/22/10
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