Editing Decibel (section)

=== Other measurements ===
; dB{{sub| Hz}} or dB‑Hz : dB(Hz) – bandwidth relative to one hertz. E.g., 20&nbsp;dB{{nbhyph}}Hz corresponds to a bandwidth of 100&nbsp;Hz. Commonly used in [[link budget]] calculations. Also used in [[carrier-to-receiver noise density|carrier-to-noise-density ratio]] (not to be confused with [[carrier-to-noise ratio]], in dB).
; [[dBFS|dB{{sub| ov}} or dB{{sub| O}}]]: dB(overload) – the amplitude of a signal (usually audio) compared with the maximum which a device can handle before [[Clipping (signal processing)|clipping]] occurs. Similar to dB FS, but also applicable to analog systems. According to ITU-T Rec. G.100.1 the level in dB ov of a digital system is defined as: <math display = "block">\ L_\mathsf{ov} = 10 \log_{10} \left( \frac{ P }{\ P_\mathsf{max}\ } \right)\ [\mathsf{dB_{ov}}]\ ,</math> with the maximum signal power <math>\ P_\mathsf{max} = 1.0\ ,</math> for a rectangular signal with the maximum amplitude <math>\ x_\mathsf{over} ~.</math> The level of a tone with a digital amplitude (peak value) of <math>\ x_\mathsf{over}\ </math> is therefore <math>\ L_\mathsf{ov} = -3.01\ \mathsf{dB_{ov}} ~.</math><ref>{{cite report |title=The use of the decibel and of relative levels in speech band telecommunications |date=June 2015 |id=ITU-T Rec. G.100.1 |publisher=[[International Telecommunication Union]] (ITU) |place=Geneva, CH |type=tech spec |url=https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.100.1-201506-I!!PDF-E&type=items }}</ref>
; dB{{sub| r}} : dB(relative) – simply a relative difference from something else, which is made apparent in context.  The difference of a filter's response to nominal levels, for instance.
; [[dBrn|dB{{sub| rn}}]] : dB above [[reference noise]].  See also '''dB{{sub| rnC}}'''
; dB{{sub| rnC}} : '''dB(rnC)''' represents an audio level measurement, typically in a telephone circuit, relative to a −90&nbsp;dB{{sub| m}} reference level, with the measurement of this level frequency-weighted by a standard C-message weighting filter. The C-message weighting filter was chiefly used in North America. The [[psophometric weighting|psophometric]] filter is used for this purpose on international circuits.{{efn|See ''[[psophometric weighting]]'' to see a comparison of frequency response curves for the C-message weighting and psophometric weighting filters.}}<ref>Definition of dB{{sub| rnC}} is given in <br/>{{cite book |editor-first=R.F. |editor-last=Rey |year=1983 |title=Engineering and Operations in the Bell System |edition=2nd |publisher=AT&T Bell Laboratories |place=Murray Hill, NJ |isbn=0-932764-04-5 |page=230 }}</ref>
; dB{{sub| K}} : '''dB(K)''' – decibels relative to 1&nbsp;[[kelvin|K]]; used to express [[noise temperature]].<ref>{{cite book |first=K.N. Raja |last=Rao |date=2013-01-31 |df=dmy-all |title=Satellite Communication: Concepts and applications |page=[{{Google books |plainurl=yes |id=pjEubAt5dk0C |page=126 }} 126] |url={{Google books |plainurl=yes |id=pjEubAt5dk0C }} |via=Google |access-date=2013-09-16 }}</ref>
; dB{{sub| K⁻¹}} or dB{{sub|/K}} : dB(K⁻¹) – decibels relative to 1&nbsp;K⁻¹.<ref>{{cite book |first=Ali Akbar |last=Arabi |year= |title=Comprehensive Glossary of Telecom Abbreviations and Acronyms |page=[{{Google books |plainurl=yes |id=DVoqmlX6048C |page=79 }} 79] |url={{Google books |plainurl=yes |id=DVoqmlX6048C }} |via=Google |access-date=2013-09-16 |df=dmy-all }}</ref> — ''not'' decibels per Kelvin: Used for the {{mvar|{{sfrac| G | T }} }} [[G/T|(G/T) factor]], a [[figure of merit]] used in [[satellite communications]], relating the [[antenna gain]] {{mvar|G}} to the [[receiver (radio)|receiver]] system noise equivalent temperature {{mvar|T}}.<ref>{{cite book |first=Mark E. |last=Long |year=1999 |title=The Digital Satellite TV Handbook |place=Woburn, MA |publisher=Newnes Press |page=[{{Google books |plainurl=yes |id=L4yQ0iztvQEC |page=93 }} 93] |url={{Google books |plainurl=yes |id=L4yQ0iztvQEC }} |access-date=2013-09-16 |df=dmy-all }}</ref><ref>{{cite book |first=Mac E. |last=van&nbsp;Valkenburg |date=2001-10-19 |df=dmy-all |title=Reference Data for Engineers: Radio, electronics, computers, and communications |series=Technology & Engineering |editor-first=Wendy M. |editor-last=Middleton |place=Woburn, MA |publisher=Newness Press |isbn=9780-08051596-0 |page=[{{Google books |plainurl=yes |id=U9RzPGwlic4C |page=SA27-PA14 }} 27·14] |url={{Google books |plainurl=yes |id=U9RzPGwlic4C }} |via=Google |access-date=2013-09-16}}</ref>