Editing Decibel (section)

== List of suffixes ==

=== Voltage ===
Since the decibel is defined with respect to power, not amplitude, conversions of voltage ratios to decibels must square the amplitude, or use the factor of 20 instead of 10, as discussed above.

[[File:Relationship between dBu and dBm.png|thumb|upright=1.25|A schematic showing the relationship between [[dBu|dB{{sub| u}}]] (the [[voltage source]]) and dB{{sub| m}} (the power dissipated as [[heat]] by the 600&nbsp;Ω [[resistor]])]]

; dB{{sub| V}} : dB(V<sub>[[root mean square|RMS]]</sub>)&nbsp;– voltage relative to 1&nbsp;volt, regardless of impedance.<ref name=clqgmk>{{cite web |title=V<sub>RMS</sub> / dBm / dBu / dBV calculator |department=Utilities |publisher=Analog Devices |url=http://designtools.analog.com/dt/dbconvert/dbconvert.html |via=designtools.analog.com |access-date=2016-09-16}}</ref> This is used to measure microphone sensitivity, and also to specify the consumer [[Line level|line-level]] of {{nowrap|−10 dBV}}, in order to reduce manufacturing costs relative to equipment using a {{nowrap|+4 dBu}} line-level signal.<ref>{{cite book |last=Winer |first=Ethan |year=2013 |title=The Audio Expert: Everything you need to know about audio |publisher=Focal Press |isbn=978-0-240-82100-9 |page=[https://books.google.com/books?id=TIfOAwAAQBAJ&q=%22%E2%88%9210+dBV%22+%221+kHz%22 107] |url=https://books.google.com/books?id=TIfOAwAAQBAJ |via=Google }}</ref>

; dB{{sub| u}} or dB{{sub| v}} : RMS voltage relative to {{nowrap|<math>V = \sqrt{600\ \Omega\ \cdot\ 0.001\ \mathsf{W}\;} \approx 0.7746\ \mathsf{V}\ </math>}} (i.e. the voltage that would dissipate 1&nbsp;mW into a 600&nbsp;Ω load). An RMS voltage of 1&nbsp;V therefore corresponds to <math>\ 20\cdot\log_{10} \left( \frac{\ 1\ V_\mathsf{RMS}\ }{ \sqrt{0.6\ }\ V} \right) = 2.218\ \mathsf{dB_u} ~.</math><ref name=clqgmk/> Originally dB{{sub| v }}, it was changed to dB{{sub| u}} to avoid confusion with dB{{sub| V}}.<ref>{{cite web |first=Stas |last=Bekman  |title=3.3 – What is the difference between dBv, dBu, dBV, dBm, dB&nbsp;SPL, and plain old dB? Why not just use regular voltage and power measurements? |website=stason.org |department=Entertainment audio |series=TULARC |url=http://stason.org/TULARC/entertainment/audio/pro/3-3-What-is-the-difference-between-dBv-dBu-dBV-dBm-dB.html }}</ref> The ''v'' comes from ''volt'', while ''u'' comes from the [[volume unit|volume ''unit'']] displayed on a [[VU meter]].<ref>{{cite AV media |first=Rupert |last=Neve |author-link=Rupert Neve |date=9 October 2015 |title=Creation of the dB{{sub| u}} standard level reference |medium=video |url=https://www.youtube.com/watch?v=b02P4f3CBuM | archive-url=https://ghostarchive.org/varchive/youtube/20211030/b02P4f3CBuM |archive-date=2021-10-30 }}{{cbignore}}</ref>{{paragraphbreak}}dB{{sub| u}} can be used as a measure of voltage, regardless of impedance, but is derived from a 600&nbsp;Ω load dissipating 0&nbsp;dB{{sub| m}} (1&nbsp;mW). The reference voltage comes from the computation <math>\ 7 \mathsf{V} = \sqrt{R \cdot P\ }\ </math> where <math>\ R\ </math> is the resistance and <math>\ P\ </math> is the power.

: In [[professional audio]], equipment may be calibrated to indicate a "0" on the VU meters some finite time after a signal has been applied at an amplitude of {{nobr|+4 dBu}}. Consumer equipment typically uses a lower "nominal" signal level of {{nobr|−10 dB{{sub| V}} .}}<ref>{{cite web |title=dB or not dB&nbsp;? |website=deltamedia.com |url=http://www.deltamedia.com/resource/db_or_not_db.html |url-status=dead |access-date=2013-09-16 |archive-url=https://web.archive.org/web/20130620064637/http://www.deltamedia.com/resource/db_or_not_db.html |archive-date=20 June 2013 }}</ref> Therefore, many devices offer dual voltage operation (with different gain or "trim" settings) for interoperability reasons. A switch or adjustment that covers at least the range between {{nobr|+4 dB{{sub| u}}}} and {{nobr|−10 dB{{sub| V}}}} is common in professional equipment.

; dB{{sub| m0s}} : Defined by Recommendation ITU-R V.574&nbsp;; dB{{sub| mV}}: dB(mV<sub>RMS</sub>) – root mean square voltage relative to 1&nbsp;millivolt across 75&nbsp;Ω.<ref>
{{cite book
 |title=The IEEE Standard Dictionary of Electrical and Electronics terms
 |edition=6th
 |year=1996
 |orig-year=1941
 |publisher=[[Institute of Electrical and Electronics Engineers]]
 |isbn=978-1-55937-833-8
}}
</ref> Widely used in [[cable television]] networks, where the nominal strength of a single TV signal at the receiver terminals is about 0&nbsp;dB{{sub| mV}}. Cable&nbsp;TV uses 75&nbsp;Ω coaxial cable, so 0&nbsp;dB{{sub| mV}} corresponds to −78.75&nbsp;dB{{sub| W}} {{nobr|( −48.75 dB{{sub| m}} )}} or approximately 13&nbsp;nW.

; dB{{sub| μV}} or dB{{sub| uV}} : dB(μV<sub>RMS</sub>) – voltage relative to 1&nbsp;microvolt. Widely used in television and aerial amplifier specifications. 60&nbsp;dBμV&nbsp;= 0&nbsp;dB{{sub| mV}}.

=== Acoustics ===
Probably the most common usage of "decibels" in reference to sound level is dB{{sub| SPL}}, sound pressure level referenced to the nominal threshold of human hearing:<ref>
{{cite book
 | title = Audio postproduction for digital video
 | first = Jay  | last = Rose
 | publisher = Focal Press
 | year = 2002
 | isbn = 978-1-57820-116-7
 | page = 25
 | url = {{Google books |plainurl=yes |id=sUcRegHAXdkC |page=25 }}
}}</ref>  The measures of pressure (a root-power quantity) use the factor of 20, and the measures of power (e.g. dB{{sub| SIL}} and dB{{sub| SWL}}) use the factor of 10.
; dB{{sub| SPL}} : dB{{sub| SPL}} (sound pressure level) – for sound in air and other gases, relative to 20&nbsp;micropascals (μPa), or {{val|2|e=-5|u=Pa}}, a level of 0&nbsp;dB{{sub| SPL}} is approximately the quietest sound a human can hear. For [[Underwater acoustics|sound in water]] and other liquids, a reference pressure of 1&nbsp;μPa is used.<ref>Morfey, C. L. (2001). Dictionary of Acoustics. Academic Press, San Diego.</ref>{{paragraphbreak}} An RMS sound pressure of one pascal corresponds to a level of 94&nbsp;dB&nbsp;SPL.
; dB{{sub| SIL}} : dB [[sound intensity level]] – relative to 10<sup>−12</sup>&nbsp;W/m<sup>2</sup>, which is roughly the [[threshold of human hearing]] in air.
; dB{{sub| SWL}} : dB [[sound power level]] – relative to 10<sup>−12</sup>&nbsp;W.
; dB{{sub| A}}, dB{{sub| B}}, and dB{{sub| C}} : These symbols are often used to denote the use of different [[weighting filter]]s, used to approximate the human ear's [[stimulus (psychology)|response]] to sound, although the measurement is still in dB&nbsp;(SPL). These measurements usually refer to noise and its effects on humans and other animals, and they are widely used in industry while discussing noise control issues, regulations and environmental standards. Other variations that may be seen are dB{{sub| A}} or dB(A). According to standards from the International Electro-technical Committee ([[IEC 61672|IEC 61672-2013]])<ref>{{cite book |title=IEC 61672-1:2013 Electroacoustics - Sound Level meters - Part 1: Specifications |date=2013 |publisher=International Electrotechnical Committee |location=Geneva}}</ref> and the American National Standards Institute, [[ANSI S1.4]],<ref>[[ANSI]] [https://law.resource.org/pub/us/cfr/ibr/002/ansi.s1.4.1983.pdf S1.4-19823 Specification for Sound Level Meters], 2.3 Sound Level, p. 2–3.</ref> the preferred usage is to write {{nobr| {{mvar|L}}{{sub| A}} {{=}} {{mvar|x}}&nbsp;dB .}} Nevertheless, the units dB{{sub| A}} and dB(A) are still commonly used as a shorthand for A{{nbhyph}}weighted measurements. Compare [[dBc|dB{{sub| c}}]], used in telecommunications.
; dB{{sub| HL}} : dB [[hearing level]] is used in [[audiogram]]s as a measure of hearing loss. The reference level varies with frequency according to a [[minimum audibility curve]] as defined in ANSI and other standards, such that the resulting audiogram shows deviation from what is regarded as 'normal' hearing.{{Citation needed|date=March 2008}}
; dB{{sub| Q}} : sometimes used to denote weighted noise level, commonly using the [[ITU-R 468 noise weighting]]{{Citation needed|date=March 2008}}
; dB{{sub| pp}} : relative to the peak to peak sound pressure.<ref>{{cite journal |last1=Zimmer |first1=Walter M.X. |first2=Mark P. |last2=Johnson |first3=Peter T. |last3=Madsen |first4=Peter L. |last4=Tyack |year=2005 |title=Echolocation clicks of free-ranging Cuvier's beaked whales (''Ziphius cavirostris'') |journal=[[The Journal of the Acoustical Society of America]] |volume=117 |issue=6 |pages=3919–3927 |doi=10.1121/1.1910225 |pmid=16018493 |bibcode=2005ASAJ..117.3919Z |hdl=1912/2358 |hdl-access=free }}</ref>
; dB{{sub| G}} : G‑weighted spectrum<ref>{{cite web | title = Turbine sound measurements |via=wustl.edu | url = http://oto2.wustl.edu/cochlea/wt4.html | url-status = dead | archive-url = https://web.archive.org/web/20101212221829/http://oto2.wustl.edu/cochlea/wt4.html | archive-date = 12 December 2010 }}</ref>

=== Audio electronics ===
See also dB{{sub| V}} and dB{{sub| u}} above.

; [[dBm|dB{{sub| m}}]] : dB(mW) – power relative to 1&nbsp;[[milliwatt]]. In audio and telephony, dB{{sub| m}} is typically referenced relative to a 600&nbsp;Ω impedance,<ref>{{cite book|last=Bigelow |first=Stephen |year=2001 |title=Understanding Telephone Electronics |publisher=Newnes Press |place=Boston, MA |isbn=978-0750671750 |page=[https://archive.org/details/isbn_9780750671750/page/16 16] |url-access=registration |url=https://archive.org/details/isbn_9780750671750/page/16 }}</ref> which corresponds to a voltage level of 0.775&nbsp;volts or 775&nbsp;millivolts.
; [[dBm0|dB{{sub| m0}}]] : Power in dB{{sub| m}} (described above) measured at a [[zero transmission level point]].
; [[dBFS|dB{{sub| FS}}]] : dB([[full scale]]) – the amplitude of a signal compared with the maximum which a device can handle before [[Clipping (signal processing)|clipping]] occurs. Full-scale may be defined as the power level of a full-scale [[Sine wave|sinusoid]] or alternatively a full-scale [[Square wave (waveform)|square wave]]. A signal measured with reference to a full-scale sine-wave appears 3&nbsp;dB weaker when referenced to a full-scale square wave, thus: 0&nbsp;dBFS(fullscale sine wave) = −3&nbsp;dB{{sub| FS}} (fullscale square wave).
; dB{{sub| VU}} : dB [[volume unit]]<ref>{{cite journal |last=Thar |first=D. |year=1998 |title=Case Studies: Transient sounds through communication headsets |journal=Applied Occupational and Environmental Hygiene |volume=13 |issue=10 |pages=691–697 |doi=10.1080/1047322X.1998.10390142 }}</ref>
; dB{{sub| TP}} : dB(true peak) – [[peak amplitude]] of a signal compared with the maximum which a device can handle before clipping occurs.<ref>[[ITU-R BS.1770]]</ref> In digital systems, 0&nbsp;dB{{sub| TP}} would equal the highest level (number) the processor is capable of representing.  Measured values are always negative or zero, since they are less than or equal to full-scale.

=== Radar ===
; [[dBZ (meteorology)|dB{{sub| Z}}]] : dB(Z) – decibel relative to Z&nbsp;= 1&nbsp;mm{{sup|6 }}⋅m{{sup|−3 }}:<ref>{{cite web |title=Terms starting with&nbsp;'''D''' |department=Glossary |publisher=U.S. [[National Weather Service]] |website=weather.gov |url=https://www.weather.gov/jetstream/glossary_d<!-- Former URL: http://www.srh.noaa.gov/jetstream/append/glossary_d.htm --> |access-date=2013-04-25 |archive-url=https://web.archive.org/web/20190808140856/https://www.weather.gov/jetstream/glossary_d |archive-date=2019-08-08 |url-status=live}}</ref> energy of reflectivity (weather radar), related to the amount of transmitted power returned to the radar receiver. Values above 20&nbsp;dB{{sub| Z}} usually indicate falling precipitation.<ref>{{cite web |title=Frequently Asked Questions |department=RIDGE Radar |publisher=U.S. [[National Weather Service]] |website=weather.gov |url=https://www.weather.gov/jetstream/radarfaq#reflcolor |access-date=2019-08-08 |archive-url=https://web.archive.org/web/20190331123302/https://www.weather.gov/jetstream/radarfaq#reflcolor |archive-date=2019-03-31 |url-status=live }}</ref>
; dB{{sub| sm}} : dB(m²) – decibel relative to one square meter: measure of the [[radar cross section]] (RCS) of a target. The power reflected by the target is proportional to its RCS. "Stealth" aircraft and insects have negative RCS measured in dB{{sub| sm }}, large flat plates or non-stealthy aircraft have positive values.<ref>{{cite web |title=dBsm |department=Definition |website=Everything&nbsp;2 |url=http://everything2.com/title/dBsm |access-date=2019-08-08 |archive-url=https://web.archive.org/web/20190610170944/https://everything2.com/title/dBsm?%2F |archive-date=10 June 2019 |url-status=live }}</ref>

=== Radio power, energy, and field strength ===
; [[dBc|dB{{sub| c}}]] : relative to carrier – in [[telecommunications]], this indicates the relative levels of noise or sideband power, compared with the carrier power. Compare dB{{sub| C}}, used in acoustics.
; dB{{sub| pp}} : relative to the maximum value of the peak power.
; dB{{sub| J}} : energy relative to 1&nbsp;[[joule]]. 1&nbsp;joule&nbsp;= 1&nbsp;watt second&nbsp;= 1&nbsp;watt per hertz, so power spectral density can be expressed in dB{{sub| J }}.
; [[dBm|dB{{sub| m}}]] : dB(mW) – power relative to 1&nbsp;[[milliwatt]]. In the radio field, dB{{sub| m}} is usually referenced to a 50&nbsp;Ω load, with the resultant voltage being 0.224&nbsp;volts.<ref>{{cite book |last=Carr |first=Joseph |author-link=Joseph Carr |year=2002 |title=RF Components and Circuits |publisher=Newnes |isbn=978-0750648448 |pages=45–46 }}</ref>
; dB{{sub| μV/m }}, dB{{sub| uV/m }}, or dB{{sub| μ }} :<ref name="dBμ">{{cite web |title=The dBμ vs. dBu mystery: Signal strength vs. field strength? |date=24 February 2015 |website=Radio Time Traveller (radio-timetraveller.blogspot.com) |type=blog |via=blogspot.com |url=http://radio-timetraveller.blogspot.com/2015/02/the-db-versus-dbu-mystery-signal.html |access-date=13 October 2016 }}</ref> dB(μV/m) – [[electric field strength]] relative to 1&nbsp;[[microvolt]] per [[meter]]. The unit is often used to specify the signal strength of a [[television]] [[broadcast]] at a receiving site (the signal measured ''at the antenna output'' is reported in dBμ{{sub| V}}).
; dB{{sub| f}} : dB(fW) – power relative to 1&nbsp;[[femtowatt]].
; dB{{sub| W}} : dB(W) – power relative to 1&nbsp;[[watt]].
; dB{{sub| k}} : dB(kW) – power relative to 1&nbsp;[[kilowatt]].
; dB{{sub| e}} : dB electrical.
; dB{{sub| o}} : dB optical. A change of 1&nbsp;dB{{sub| o}} in optical power can result in a change of up to 2&nbsp;dB{{sub| e}} in electrical signal power in a system that is thermal noise limited.<ref>{{cite journal |last1=Chand |first1=N. |last2=Magill |first2=P.D. |last3=Swaminathan |first3=S.V. |last4=Daugherty |first4=T.H. |year=1999 |title=Delivery of digital video and other multimedia services {{nobr|( > 1 Gb/s}} bandwidth) in passband above the 155&nbsp;Mb/s baseband services on a FTTx full service access network |journal=Journal of Lightwave Technology |volume=17 |issue=12 |pages=2449–2460 |doi=10.1109/50.809663 }}</ref>

=== Antenna measurements ===
; dB{{sub| i}} : dB(isotropic) <span id="dBi_anchor" class="anchor"></span> – the [[antenna gain|gain]] of an antenna compared with the gain of a theoretical [[isotropic antenna]], which uniformly distributes energy in all directions. [[Linear polarization]] of the EM field is assumed unless noted otherwise.
; dB{{sub| d}} : dB(dipole) – the [[antenna gain|gain]] of an [[antenna (electronics)|antenna]] compared with the gain a half-wave [[dipole antenna]]. 0&nbsp;dBd&nbsp;= 2.15&nbsp;dBi
; dB{{sub| iC}} : dB(isotropic circular) – the gain of an antenna compared to the gain of a theoretical [[Circular polarization|circularly polarized]] isotropic antenna. There is no fixed conversion rule between dB{{sub|iC}} and dB{{sub|i}}, as it depends on the receiving antenna and the field polarization.
; dB{{sub| q}} : dB(quarterwave) – the [[antenna gain|gain]] of an antenna compared to the gain of a quarter wavelength whip. Rarely used, except in some marketing material; {{nobr|0 dB{{sub|q}}}}&nbsp;= {{nobr|−0.85 dB{{sub|i}}}}
; dB{{sub| sm}} : dB{{sub| m²}}, dB(m²) – decibels relative to one square meter: A measure of the [[antenna effective area|effective area]] for capturing signals of the antenna.<ref>{{cite book |first=David |last=Adamy |year=2004 |title=EW&nbsp;102: A second course in electronic warfare |series=Artech House Radar Library |place=Boston, MA |publisher=Artech House |isbn=9781-58053687-5 |page=[{{Google books |plainurl=yes |id=-AkfVZskc64C |page=118 }} 118] |url={{Google books |plainurl=yes |id=-AkfVZskc64C }} |via=Google |access-date=2013-09-16}}</ref>
; dB{{sub| m⁻¹}} : dB(m{{sup|−1}}) – decibels relative to reciprocal of meter: measure of the [[antenna factor]].

=== 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>

=== List of suffixes in alphabetical order ===

==== Unpunctuated suffixes ====
; dB{{sub| A}} : see [[dB(A)]].
; dB{{sub| a}} : see [[dBrn adjusted|dB{{sub| rn}} adjusted]].
; dB{{sub| B}} : see [[dB(B)]].
; [[dBc|dB{{sub| c}}]] : relative to carrier – in [[telecommunications]], this indicates the relative levels of noise or sideband power, compared with the carrier power. 
; dB{{sub| C}} : see [[dB(C)]].
; dB{{sub| D}} : see [[dB(D)]].
; dB{{sub| d}} : dB(dipole) – the forward gain of an [[antenna (electronics)|antenna]] compared with a half-wave [[dipole antenna]]. 0&nbsp;dBd = 2.15&nbsp;dB{{sub| i}}
; dB{{sub| e}} : dB electrical.
; dB{{sub| f}} : dB(fW) – power relative to 1&nbsp;[[femtowatt]].
; [[dBFS|dB{{sub| FS}}]] : dB([[full scale]]) – the amplitude of a signal compared with the maximum which a device can handle before [[clipping (signal processing)|clipping]] occurs. Full-scale may be defined as the power level of a full-scale [[Sine wave|sinusoid]] or alternatively a full-scale [[Square wave (waveform)|square wave]]. A signal measured with reference to a full-scale sine-wave appears 3&nbsp;dB weaker when referenced to a full-scale square wave, thus: 0&nbsp;dB{{sub| FS}} (fullscale sine wave)&nbsp;= −3&nbsp;dB{{sub| FS}} (full-scale square wave).
; dB{{sub| G}} : [[G-weighted]] spectrum
; dB{{sub| i}} : dB(isotropic) – the forward [[antenna gain|gain of an antenna]] compared with the hypothetical [[isotropic antenna]], which uniformly distributes energy in all directions. [[Linear polarization]] of the EM field is assumed unless noted otherwise.
; dB{{sub| iC}} : dB(isotropic circular) – the forward gain of an antenna compared to a [[Circular polarization|circularly polarized]] isotropic antenna. There is no fixed conversion rule between dB{{sub| iC}} and dB{{sub| i }}, as it depends on the receiving antenna and the field polarization.
; dB{{sub| J}} : energy relative to 1&nbsp;[[joule]]: 1&nbsp;joule&nbsp;= 1&nbsp;watt-second&nbsp;= 1 watt per hertz, so power spectral density can be expressed in dB{{sub| J }}.
; dB{{sub| k}} : dB(kW) – power relative to 1&nbsp;[[kilowatt]].
; dB{{sub| K}} :'''dB(K)''' – decibels relative to [[kelvin]]: Used to express [[noise temperature]].
; [[dBm|dB{{sub| m}}]] : dB(mW) – power relative to 1 [[milliwatt]]. 
; dB{{sub| m²}} or dB{{sub| sm}} : dB(m²) – decibel relative to one square meter
; [[dBm0|dB{{sub| m0}}]] : Power in dB{{sub| m}} measured at a zero transmission level point.
; dB{{sub| m0s}} : Defined by ''Recommendation ITU-R V.574''.
; dB{{sub| mV}} : dB(mV<sub>RMS</sub>) – voltage relative to 1&nbsp;millivolt across 75&nbsp;Ω.
; dB{{sub| o}} : dB optical. A change of 1&nbsp;dB{{sub| o}} in optical power can result in a change of up to 2&nbsp;dB{{sub| e}} in electrical signal power in system that is thermal noise limited.
; dB{{sub| O}} : see dB{{sub| ov}} 
; 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.
; dB{{sub| pp}} : relative to the peak to peak [[sound pressure]].
; dB{{sub| pp}} : relative to the maximum value of the peak [[electrical power]].
; dB{{sub| q}} : dB(quarterwave) – the forward gain of an antenna compared to a quarter wavelength whip. Rarely used, except in some marketing material. 0&nbsp;dBq&nbsp;= −0.85&nbsp;dB{{sub| i}}
; 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{{sub| rnC}}''' represents an audio level measurement, typically in a telephone circuit, relative to the [[circuit noise 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.
; dB{{sub| sm}} : see dB{{sub| m²}}
; dB{{sub| TP}} : dB(true peak) – [[peak amplitude]] of a signal compared with the maximum which a device can handle before clipping occurs.
; dB{{sub| u}} or dB{{sub| v}} : RMS voltage relative to <math>\ \sqrt{0.6\; }\ \mathsf{V}\ \approx 0.7746\ \mathsf{V}\ \approx -2.218\ \mathsf{dB_V} ~.</math>
; dB{{sub| u0s}} : Defined by ''Recommendation ITU-R V.574''.
; dB{{sub| uV}} : see dB{{sub| μV}}
; dB{{sub| uV/m}} : see dB{{sub| μV/m}}
; dB{{sub| v}} : see dB{{sub| u}}
; dB{{sub| V}} : dB(V<sub>RMS</sub>) – voltage relative to 1 volt, regardless of impedance.
; dB{{sub| VU}} : dB(VU) dB [[volume unit]]
; dB{{sub| W}} : dB(W) – power relative to 1&nbsp;[[watt]].
; dB{{sub| W·m⁻²·Hz⁻¹}} : [[Jansky#dBW·m−2·Hz−1|spectral density]] relative to 1 W·m⁻²·Hz⁻¹<ref>{{cite web |title=Units and calculations |website=iucaf.org |url=http://www.iucaf.org/sschool/mike/Units_and_Calculations.ppt |last1=Davis |first1=Mike |format=PPT |date=June 2002 |access-date=2025-03-12 |url-status=live |archive-url=https://web.archive.org/web/20160303223821/http://www.iucaf.org/sschool/mike/Units_and_Calculations.ppt |archive-date=2016-03-03 }}</ref>
; [[DBZ (meteorology)|dB{{sub| Z}}]] : dB(Z) – decibel relative to Z&nbsp;= 1&nbsp;mm<sup>6</sup>⋅m<sup>−3</sup>
; dB{{sub| μ}} : see dB{{sub| μV/m}}
; dB{{sub| μV}} or dB{{sub| uV}} : dB(μV<sub>RMS</sub>) – voltage relative to 1&nbsp;root mean square microvolt.
; dB{{sub| μV/m }}, dB{{sub| uV/m }}, or dB{{sub| μ }} : dB(μV/m) – [[electric field strength]] relative to 1&nbsp;[[microvolt]] per [[meter]].

==== Suffixes preceded by a space ====
; dB HL : dB hearing level is used in [[audiogram]]s as a measure of hearing loss. 
; dB Q : sometimes used to denote weighted noise level
; dB SIL : dB [[sound intensity level]] – relative to 10<sup>−12</sup>&nbsp;W/m<sup>2</sup> 
; dB SPL : dB SPL (sound pressure level) – for sound in air and other gases, relative to 20&nbsp;μPa in air or 1&nbsp;μPa in water
; dB SWL : dB [[sound power level]] – relative to 10<sup>−12</sup>&nbsp;W.

==== Suffixes within parentheses ====
; [[dB(A)]], [[dB(B)]], [[dB(C)]], [[dB(D)]], [[dB(G)]],<!-- possibly also dB(M), but I haven't seen this in practise yet --> and [[dB(Z)]] : These symbols are often used to denote the use of different [[weighting filter]]s, used to approximate the human ear's [[Stimulus (psychology)|response]] to sound, although the measurement is still in dB (SPL). These measurements usually refer to noise and its effects on humans and other animals, and they are widely used in industry while discussing noise control issues, regulations and environmental standards. Other variations that may be seen are dB<sub>A</sub> or dBA.

==== Other suffixes ====
; dB{{sub| Hz}} or dB-Hz : dB(Hz) – bandwidth relative to one [[Hertz (unit)|Hertz]]
;  dB{{sub| K⁻¹}} or dB{{sub| /K}} : dB(K⁻¹) – decibels relative to [[multiplicative inverse|reciprocal]] of [[kelvin]]
; dB{{sub| m⁻¹}} : dB(m⁻¹) – decibel relative to reciprocal of meter: measure of the [[antenna factor]]

; mB{{sub| m}} : {{anchor|Millibel}} mB(mW) – power relative to 1&nbsp;[[milliwatt]], in millibels (one hundredth of a decibel). 100&nbsp;mB{{sub| m}} = 1&nbsp;dB{{sub| m }}. This unit is in the Wi-Fi drivers of the [[Linux]] kernel<ref>{{cite web |title=Setting {{sc|TX}} power |series=en:users:documentation:iw |website=wireless.kernel.org |url=http://wireless.kernel.org/en/users/Documentation/iw#Setting_TX_power }}</ref> and the regulatory domain sections.<ref>{{cite web |title=Is your Wi Fi ap missing channels&nbsp;12 and 13&nbsp;? |date=16 May 2013 |website=Pentura Labs |via=wordpress.com  |url=http://penturalabs.wordpress.com/2013/05/16/is-your-wifi-ap-missing-channels-12-13/ }}</ref>