It is essential to know which category a measurement belongs to when using decibels (dB) for comparing the levels of such quantities. A change of one bel in the level corresponds to a 10× change in power, so when comparing power quantities x and y, the difference is defined to be 10×log10(y/x) decibel. With root-power quantities, however the difference is defined as 20×log10(y/x) dB.[3]
In the analysis of signals and systems using sinusoids, field quantities and root-power quantities may be complex-valued.[4][5][6][disputed – discuss]
"Root-power quantity" vs. "field quantity"
In justifying the deprecation of the term "field quantity" and instead using "root-power quantity" in the context of levels, ISO 80000 draws attention to the conflicting use of the former term to mean a quantity that depends on the position,[7] which in physics is called a field. Such a field is often called a field quantity in the literature, but is called a field here for clarity. Several types of field (such as the electromagnetic field) meet the definition of a root-power quantity, whereas others (such as the Poynting vector and temperature) do not. Conversely, not every root-power quantity is a field (such as the voltage on a loudspeaker).
Sound level, defined for each of several quantities associated with sound
References
^Ainslie, Michael A. (Winter 2015). "A Century of Sonar: Planetary Oceanography, Underwater Noise Monitoring, and the Terminology of Underwater Sound" (PDF). Acoustics Today. 11 (1): 12–19.
power, root, power, field, quantities, power, quantity, power, quantity, directly, proportional, power, energy, density, acoustic, intensity, luminous, intensity, energy, quantities, also, labelled, power, quantities, this, context, root, power, quantity, quan. A power quantity is a power or a quantity directly proportional to power e g energy density acoustic intensity and luminous intensity 1 Energy quantities may also be labelled as power quantities in this context 2 A root power quantity is a quantity such as voltage current sound pressure electric field strength speed or charge density the square of which in linear systems is proportional to power 3 The term root power quantity refers to the square root that relates these quantities to power The term was introduced in ISO 80000 1 Annex C it replaces and deprecates the term field quantity Contents 1 Implications 2 Root power quantity vs field quantity 3 See also 4 ReferencesImplications EditIt is essential to know which category a measurement belongs to when using decibels dB for comparing the levels of such quantities A change of one bel in the level corresponds to a 10 change in power so when comparing power quantities x and y the difference is defined to be 10 log10 y x decibel With root power quantities however the difference is defined as 20 log10 y x dB 3 In the analysis of signals and systems using sinusoids field quantities and root power quantities may be complex valued 4 5 6 disputed discuss Root power quantity vs field quantity EditIn justifying the deprecation of the term field quantity and instead using root power quantity in the context of levels ISO 80000 draws attention to the conflicting use of the former term to mean a quantity that depends on the position 7 which in physics is called a field Such a field is often called a field quantity in the literature but is called a field here for clarity Several types of field such as the electromagnetic field meet the definition of a root power quantity whereas others such as the Poynting vector and temperature do not Conversely not every root power quantity is a field such as the voltage on a loudspeaker See also EditLevel logarithmic quantity Fresnel reflection field and power equations Sound level defined for each of several quantities associated with soundReferences Edit Ainslie Michael A Winter 2015 A Century of Sonar Planetary Oceanography Underwater Noise Monitoring and the Terminology of Underwater Sound PDF Acoustics Today 11 1 12 19 ISO 80000 1 2009 C 3 a b Brian C J Moore 1995 Hearing Academic Press p 11 ISBN 978 0 08 053386 5 ISO 80000 1 2009 C 2 ISO 80000 3 2006 0 5 IEC 60027 3 2002 ISO 80000 1 2009 C 2 Retrieved from https en wikipedia org w index php title Power root power and field quantities amp oldid 1019286952, wikipedia, wiki, book, books, library,
