Knowledge (XXG)

Decibel

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3048:
found to be 87 dBA but when the machine is switched off the background noise alone is measured as 83 dBA. the machine noise may be obtained by 'subtracting' the 83 dBA background noise from the combined level of 87 dBA; i.e., 84.8 dBA.; in order to find a representative value of the sound level in a room a number of measurements are taken at different positions within the room, and an average value is calculated. Compare the logarithmic and arithmetic averages of 70 dB and 90 dB:
3528: 4183: 213:(TU). 1 TU was defined such that the number of TUs was ten times the base-10 logarithm of the ratio of measured power to a reference power. The definition was conveniently chosen such that 1 TU approximated 1 MSC; specifically, 1 MSC was 1.056 TU. In 1928, the Bell system renamed the TU into the decibel, being one tenth of a newly defined unit for the base-10 logarithm of the power ratio. It was named the 8258: 3202: 2194:. An example might be an amplifier with unity voltage gain independent of load and frequency driving a load with a frequency-dependent impedance: the relative voltage gain of the amplifier is always 0 dB, but the power gain depends on the changing spectral composition of the waveform being amplified. Frequency-dependent impedances may be analyzed by considering the quantities 4158:
of μV for microvolt), sometimes it is an acronym for the unit's name ("sm" for square meter, "m" for milliwatt), other times it is a mnemonic for the type of quantity being calculated ("i" for antenna gain with respect to an isotropic antenna, "λ" for anything normalized by the EM wavelength), or otherwise a general attribute or identifier about the nature of the quantity ("A" for
3523:{\displaystyle {\begin{aligned}M_{\text{lm}}(70,90)&=\left(70\,{\text{dBA}}+90\,{\text{dBA}}\right)/2\\&=10\cdot \log _{10}\left({\bigl (}10^{70/10}+10^{90/10}{\bigr )}/2\right)\,{\text{dBA}}\\&=10\cdot \left(\log _{10}{\bigl (}10^{70/10}+10^{90/10}{\bigr )}-\log _{10}2\right)\,{\text{dBA}}\approx 87\,{\text{dBA}}\end{aligned}}} 1703: 233:
thereafter. This unit was employed up to 1923 when a new unit was adopted as being more suitable for modern telephone work. The new transmission unit is widely used among the foreign telephone organizations and recently it was termed the "decibel" at the suggestion of the International Advisory Committee on Long Distance Telephony.
2937:). Practically, this means that, armed only with the knowledge that 1 dB is a power gain of approximately 26%, 3 dB is approximately 2× power gain, and 10 dB is 10× power gain, it is possible to determine the power ratio of a system from the gain in dB with only simple addition and multiplication. For example: 3064:, and can be defined by taking exponentials to convert to a linear scale, adding there, and then taking logarithms to return. For example, where operations on decibels are logarithmic addition/subtraction and logarithmic multiplication/division, while operations on the linear scale are the usual operations: 3038:
According to Mitschke, "The advantage of using a logarithmic measure is that in a transmission chain, there are many elements concatenated, and each has its own gain or attenuation. To obtain the total, addition of decibel values is much more convenient than multiplication of the individual factors."
7461:
Chand, N., Magill, P. D., Swaminathan, S. V., & Daugherty, T. H. (1999). Delivery of digital video and other multimedia services (> 1 Gb/s bandwidth) in passband above the 155 Mb/s baseband services on a FTTx full service access network. Journal of lightwave technology, 17(12),
4157:
Outside of documents adhering to SI units, the practice is very common as illustrated by the following examples. There is no general rule, with various discipline-specific practices. Sometimes the suffix is a unit symbol ("W","K","m"), sometimes it is a transliteration of a unit symbol ("uV" instead
4041:
quoted as 40 dB represents a ratio of 100:1 between optical signal intensity and optical-equivalent dark-noise intensity, not a 10,000:1 intensity (power) ratio as 40 dB might suggest. Sometimes the 20 log ratio definition is applied to electron counts or photon counts directly, which
240:
decibels when they are in the ratio of 10. The number of transmission units expressing the ratio of any two powers is therefore ten times the common logarithm of that ratio. This method of designating the gain or loss of power in telephone circuits permits direct addition or subtraction of the units
90:
The unit represents a relative value, expressed as a ratio. The relative value can sometimes represent an absolute value by using a fixed reference value in the denominator; when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. For example, for
5289:
represents an audio level measurement, typically in a telephone circuit, relative to a -90 dBm 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 filter
4640:
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
3047:
level of, say, 90 dB at a certain point, then when both are operating together we should expect the combined sound pressure level to increase to 93 dB, but certainly not to 180 dB!; suppose that the noise from a machine is measured (including the contribution of background noise) and
5978:
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
2868:
The decibel is useful for representing large ratios and for simplifying representation of multiplicative effects, such as attenuation from multiple sources along a signal chain. Its application in systems with additive effects is less intuitive, such as in the combined sound pressure level of two
232:
Since the earliest days of the telephone, the need for a unit in which to measure the transmission efficiency of telephone facilities has been recognized. The introduction of cable in 1896 afforded a stable basis for a convenient unit and the "mile of standard" cable came into general use shortly
3196: 4045:
However, as mentioned above, the 10 log intensity convention prevails more generally in physical optics, including fiber optics, so the terminology can become murky between the conventions of digital photographic technology and physics. Most commonly, quantities called "dynamic range" or
6140:"When one gives the value of a quantity, any information concerning the quantity or its conditions of measurement must be presented in such a way as not to be associated with the unit. This means that quantities must be defined so that they can be expressed solely in acceptable units..." 4046:"signal-to-noise" (of the camera) would be specified in 20 log dB, but in related contexts (e.g. attenuation, gain, intensifier SNR, or rejection ratio) the term should be interpreted cautiously, as confusion of the two units can result in very large misunderstandings of the value. 1335: 4782:
of a signal compared with the maximum which a device can handle before clipping occurs. In digital systems, 0 dBTP 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
114:
of the root-power quantity by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude.
4153:
relative to 1 μV/m reference value. If the measurement result 20 dB is presented separately, it can be specified using the information in parentheses, which is then part of the surrounding text and not a part of the unit: 20 dB (re: 1 μV/m) or 20 dB (1 μV/m).
2210:
Since logarithm differences measured in these units often represent power ratios and root-power ratios, values for both are shown below. The bel is traditionally used as a unit of logarithmic power ratio, while the neper is used for logarithmic root-power (amplitude) ratio.
4069:
This form of attaching suffixes to dB is widespread in practice, albeit being against the rules promulgated by standards bodies (ISO and IEC), given the "unacceptability of attaching information to units" and the "unacceptability of mixing information with units". The
1533: 4029:, decibels generally represent ratios of video voltages or digitized light intensities, using 20 log of the ratio, even when the represented intensity (optical power) is directly proportional to the voltage generated by the sensor, not to its square, as in a 6131:"When one gives the value of a quantity, it is incorrect to attach letters or other symbols to the unit in order to provide information about the quantity or its conditions of measurement. Instead, the letters or other symbols should be attached to the quantity." 2474: 3854:
in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is equal to or greater than 1 trillion (10). Such large measurement ranges are conveniently expressed in
2588: 3859:: the base-10 logarithm of 10 is 12, which is expressed as a sound intensity level of 120 dB re 1 pW/m. The reference values of I and p in air have been chosen such that this corresponds approximately to a sound pressure level of 120 dB re 20  2712: 4404: 2950:
Calculated precisely, the output is 1 W × 10 ≈ 316.2 W. The approximate value has an error of only +0.4% with respect to the actual value, which is negligible given the precision of the values supplied and the accuracy of most measurement
3730: 1885: 4065:
In cases where the unit value of the reference is stated, the decibel value is known as "absolute". If the unit value of the reference is not explicitly stated, as in the dB gain of an amplifier, then the decibel value is considered relative.
5766: 186:
per second (795.8 Hz), and matched closely the smallest attenuation detectable to a listener. A standard telephone cable was "a cable having uniformly distributed resistance of 88 ohms per loop-mile and uniformly distributed
3845: 4307: 2941:
A system consists of 3 amplifiers in series, with gains (ratio of power out to in) of 10 dB, 8 dB, and 7 dB respectively, for a total gain of 25 dB. Broken into combinations of 10, 3, and 1 dB, this is:
4546:
networks, where the nominal strength of a single TV signal at the receiver terminals is about 0 dBmV. Cable TV uses 75 Ω coaxial cable, so 0 dBmV corresponds to −78.75 dBW (−48.75 dBm) or approximately
7251:
Zimmer, Walter MX, Mark P. Johnson, Peter T. Madsen, and Peter L. Tyack. "Echolocation clicks of free-ranging Cuvier’s beaked whales (Ziphius cavirostris)." The Journal of the Acoustical Society of America 117, no. 6 (2005):
3070: 2161: 4798:
dB(Z) – decibel relative to Z = 1 mm⋅m: energy of reflectivity (weather radar), related to the amount of transmitted power returned to the radar receiver. Values above 20 dBZ usually indicate falling
5133: 2039: 1217: 4006:, and the losses, in dB (decibels), of each component (e.g., connectors, splices, and lengths of fiber) are known, the overall link loss may be quickly calculated by addition and subtraction of decibel quantities. 2781: 4809:(RCS) of a target. The power reflected by the target is proportional to its RCS. "Stealth" aircraft and insects have negative RCS measured in dBsm, large flat plates or non-stealthy aircraft have positive values. 3951:
The decibel unit can also be combined with a reference level, often indicated via a suffix, to create an absolute unit of electric power. For example, it can be combined with "m" for "milliwatt" to produce the
3928:) can be calculated simply by summing the decibel gains of the individual components. Similarly, in telecommunications, decibels denote signal gain or loss from a transmitter to a receiver through some medium ( 4578:
referenced to the nominal threshold of human hearing: The measures of pressure (a root-power quantity) use the factor of 20, and the measures of power (e.g. dB SIL and dB SWL) use the factor of 10.
5482:. A signal measured with reference to a full-scale sine-wave appears 3 dB weaker when referenced to a full-scale square wave, thus: 0 dBFS(fullscale sine wave) = −3 dBFS(fullscale square wave). 4766:. A signal measured with reference to a full-scale sine-wave appears 3 dB weaker when referenced to a full-scale square wave, thus: 0 dBFS(fullscale sine wave) = −3 dBFS(fullscale square wave). 2605:
has the same value, 30 dB, regardless of whether it is obtained from powers or from amplitudes, provided that in the specific system being considered power ratios are equal to amplitude ratios squared.
4166:, as in "dB‑Hz", or with a space, as in "dB HL", or enclosed in parentheses, as in "dB(sm)", or with no intervening character, as in "dBm" (which is non-compliant with international standards). 2377: 2495: 4061:
Suffixes are commonly attached to the basic dB unit in order to indicate the reference value by which the ratio is calculated. For example, dBm indicates power measurement relative to 1 milliwatt.
2621: 1772: 1500: 7701:
Tuffentsammer, Karl (1956). "Das Dezilog, eine Brücke zwischen Logarithmen, Dezibel, Neper und Normzahlen" [The decilog, a bridge between logarithms, decibel, neper and preferred numbers].
1527:(reference). This is because the definitions were originally formulated to give the same value for relative ratios for both power and root-power quantities. Thus, the following definition is used: 1698:{\displaystyle L_{F}=\ln \!\left({\frac {F}{F_{0}}}\right)\,{\text{Np}}=10\log _{10}\!\left({\frac {F^{2}}{F_{0}^{2}}}\right)\,{\text{dB}}=20\log _{10}\left({\frac {F}{F_{0}}}\right)\,{\text{dB}}} 4179:
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.
3599:
or ratio to distance of transmission. In this case, dB/m represents decibel per meter, dB/mi represents decibel per mile, for example. These quantities are to be manipulated obeying the rules of
3207: 1939:
Although power and root-power quantities are different quantities, their respective levels are historically measured in the same units, typically decibels. A factor of 2 is introduced to make
1340:
The base-10 logarithm of the ratio of the two power quantities is the number of bels. The number of decibels is ten times the number of bels (equivalently, a decibel is one-tenth of a bel).
4426:.dBu can be used as a measure of voltage, regardless of impedance, but is derived from a 600 Ω load dissipating 0 dBm (1 mW). The reference voltage comes from the computation 4516:. 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 4317: 5257: 4461: 7508:
dBrnC is defined on page 230 in "Engineering and Operations in the Bell System," (2ed), R.F. Rey (technical editor), copyright 1983, AT&T Bell Laboratories, Murray Hill, NJ,
209:
received a favorable response to a new unit definition among members of the International Advisory Committee on Long Distance Telephony in Europe and replaced the MSC with the
5220: 5193: 3650: 2905:
Level values in decibels can be added instead of multiplying the underlying power values, which means that the overall gain of a multi-component system, such as a series of
4986:
dB(quarterwave) – the gain of an antenna compared to the gain of a quarter wavelength whip. Rarely used, except in some marketing material. 0 dBq = −0.85 dBi
3571: 5652:
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.
5265:
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.
1808: 4726:. In audio and telephony, dBm is typically referenced relative to a 600 Ω impedance, which corresponds to a voltage level of 0.775 volts or 775 millivolts. 1947:
waveform is under consideration with changes in amplitude, or the medium impedance is linear and independent of both frequency and time. This relies on the relationship
5712: 272:(ISO). The IEC permits the use of the decibel with root-power quantities as well as power and this recommendation is followed by many national standards bodies, such as 5166: 257: 5680:, 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. 4931:
dB optical. A change of 1 dBo in optical power can result in a change of up to 2 dBe in electrical signal power in a system that is thermal noise limited.
5646:
dB(quarterwave) – the forward gain of an antenna compared to a quarter wavelength whip. Rarely used, except in some marketing material. 0 dBq = −0.85 dBi
5050: 269: 236:
The decibel may be defined by the statement that two amounts of power differ by 1 decibel when they are in the ratio of 10 and any two amounts of power differ by
225: 4502: 4482: 3896:. Similarly to the use in acoustics, a frequency weighted power is often used. For audio noise measurements in electrical circuits, the weightings are called 3772: 4254: 2827:. Likewise, a doubling or halving of the voltage, corresponding to a quadrupling or quartering of the power, is commonly described as 6 dB rather than ± 1107:
Therefore, the bel represents the logarithm of a ratio between two power quantities of 10:1, or the logarithm of a ratio between two root-power quantities of
2723: 8233: 3191:{\displaystyle 87\,{\text{dBA}}\ominus 83\,{\text{dBA}}=10\cdot \log _{10}{\bigl (}10^{87/10}-10^{83/10}{\bigr )}\,{\text{dBA}}\approx 84.8\,{\text{dBA}}} 7647: 5608:
dB optical. A change of 1 dBo in optical power can result in a change of up to 2 dBe in electrical signal power in system that is thermal noise limited.
245:
In 1954, J. W. Horton argued that the use of the decibel as a unit for quantities other than transmission loss led to confusion, and suggested the name
6502:. International Electrotechnical Commission. 19 July 2002. Part 3: Logarithmic and related quantities, and their units. IEC 60027-3, Ed. 3.0. 5047:
occurs. Similar to dBFS, but also applicable to analog systems. According to ITU-T Rec. G.100.1 the level in dBov of a digital system is defined as:
265: 3616:
The human perception of the intensity of sound and light more nearly approximates the logarithm of intensity rather than a linear relationship (see
2083: 1104:. Finally, the level of a quantity is the logarithm of the ratio of the value of that quantity to a reference value of the same kind of quantity. 8297: 7095:"3.3 – What is the difference between dBv, dBu, dBV, dBm, dB SPL, and plain old dB? Why not just use regular voltage and power measurements?" 2909:
stages, can be calculated by summing the gains in decibels of the individual components, rather than multiply the amplification factors; that is,
1953: 1511: 1165: 68: 7312:
Tharr, D. (1998). Case Studies: Transient Sounds Through Communication Headsets. Applied Occupational and Environmental Hygiene, 13(10), 691–697.
4602:
and other liquids, a reference pressure of 1 μPa is used. An RMS sound pressure of one pascal corresponds to a level of 94 dB SPL.
3039:
However, for the same reason that humans excel at additive operation over multiplication, decibels are awkward in inherently additive operations:
1330:{\displaystyle L_{P}={\frac {1}{2}}\ln \!\left({\frac {P}{P_{0}}}\right)\,{\text{Np}}=10\log _{10}\!\left({\frac {P}{P_{0}}}\right)\,{\text{dB}}} 170:
The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was
6058: 7094: 7198: 7171: 7077: 7050: 7021: 6994: 6967: 6907: 6584: 6337: 6287: 6210: 5519:
isotropic antenna. There is no fixed conversion rule between dBiC and dBi, as it depends on the receiving antenna and the field polarization.
4980:
isotropic antenna. There is no fixed conversion rule between dBiC and dBi, as it depends on the receiving antenna and the field polarization.
4661: = x dB. Nevertheless, the units dBA and dB(A) are still commonly used as a shorthand for A‑weighted measurements. Compare 8292: 7625: 2869:
machines operating together. Care is also necessary with decibels directly in fractions and with the units of multiplicative operations.
2063:
For differences in level, the required relationship is relaxed from that above to one of proportionality (i.e., the reference quantities
2060:
is frequency- or time-dependent, this relationship does not hold in general, for example if the energy spectrum of the waveform changes.
2814: dB, but this is almost universally rounded to 3 dB in technical writing. This implies an increase in voltage by a factor of 7949: 7420: 7297: 7496: 4508:, 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 7797: 7513: 6940: 6852:
Chapman, D. M., & Ellis, D. D. (1998). Elusive decibel: Thoughts on sonars and marine mammals. Canadian Acoustics, 26(2), 29-31.
5024: 4683:
as defined in ANSI and other standards, such that the resulting audiogram shows deviation from what is regarded as 'normal' hearing.
3874:
being the most common standard) to get the weighted acoustic power before converting to a sound level or noise level in decibels.
6479: 4224:
relative to 1 volt, regardless of impedance. This is used to measure microphone sensitivity, and also to specify the consumer
7363: 7137: 4828:, this indicates the relative levels of noise or sideband power, compared with the carrier power. Compare dBC, used in acoustics. 8139: 5019:
dB(Hz) – bandwidth relative to one hertz. E.g., 20 dB‑Hz corresponds to a bandwidth of 100 Hz. Commonly used in
3929: 2881:
nature of the decibel means that a very large range of ratios can be represented by a convenient number, in a manner similar to
2202:, which allows elimination of the frequency dependence in the analysis by analyzing the system at each frequency independently. 1714: 1442: 102:
Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the
4565:
relative to 1 microvolt. Widely used in television and aerial amplifier specifications. 60 dBμV = 0 dBmV.
4042:
are proportional to sensor signal amplitude without the need to consider whether the voltage response to intensity is linear.
8243: 6702: 6559: 2968: 2959:
than to modern digital processing, and is cumbersome and difficult to interpret. Quantities in decibels are not necessarily
3024:. However, the linear-scale units still simplify in the implied fraction, so that the results would be expressed in dB-Hz. 7958: 7729: 7337: 6381: 6066: 4735: 3978:. When used in a 600-ohm circuit (historically, the standard reference impedance in telephone circuits), dBu and dBm are 3640:. The reference pressure for sound in air is set at the typical threshold of perception of an average human and there are 261: 7764: 7436: 7067: 5625: 5471: 5044: 4755: 1184: 1060: 76: 6263: 4860:. In the radio field, dBm is usually referenced to a 50 Ω load, with the resultant voltage being 0.224 volts. 2469:{\displaystyle L_{G}=10\log _{10}\left({\frac {1\,000\,{\text{W}}}{1\,{\text{W}}}}\right)\,{\text{dB}}=30\,{\text{dB}}} 7679: 3760:
Use of the decibel in underwater acoustics leads to confusion, in part because of this difference in reference value.
2583:{\displaystyle L_{G}=20\log _{10}\left({\frac {31.62\,{\text{V}}}{1\,{\text{V}}}}\right)\,{\text{dB}}=30\,{\text{dB}}} 6261:
Thompson and Taylor 2008, Guide for the Use of the International System of Units (SI), NIST Special Publication SP811
2044:
holding. In a nonlinear system, this relationship does not hold by the definition of linearity. However, even in a
264:(SI), but decided against the proposal. However, the decibel is recognized by other international bodies such as the 7389: 7262: 2955:
However, according to its critics, the decibel creates confusion, obscures reasoning, is more related to the era of
8287: 4613: 2897:. For example, 120 dB SPL may be clearer than "a trillion times more intense than the threshold of hearing". 2707:{\displaystyle L_{G}=10\log _{10}\left({\frac {10{\text{W}}}{0.001{\text{W}}}}\right)\,{\text{dB}}=40\,{\text{dB}}} 6680:
Andrew Clennel Palmer (2008), Dimensional Analysis and Intelligent Experimentation, World Scientific, 154 pp, p.13
3866:
Since the human ear is not equally sensitive to all sound frequencies, the acoustic power spectrum is modified by
3603:, e.g., a 100-meter run with a 3.5 dB/km fiber yields a loss of 0.35 dB = 3.5 dB/km × 0.1 km. 110:
by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in
6034:, in millibels (one hundredth of a decibel). 100 mBm = 1 dBm. This unit is in the Wi-Fi drivers of the 4690: 4399:{\displaystyle 20\cdot \log _{10}\left({\frac {1\,V_{\text{RMS}}}{{\sqrt {0.6}}\,V}}\right)=2.218\,{\text{dBu}}.} 3956:". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW). 2314: 1068: 6659:
Hickling, R. (2006). Decibels and octaves, who needs them?. Journal of sound and vibration, 291(3-5), 1202-1207.
5294:
to see a comparison of frequency response curves for the C-message weighting and Psophometric weighting filters.
8197: 5332: 4680: 3925: 39: 3766:
is proportional to the square of sound pressure. Therefore the sound intensity level can also be defined as:
1516:
When referring to measurements of root-power quantities, it is usual to consider the ratio of the squares of
130:, but the bel is seldom used. Instead, the decibel is used for a wide variety of measurements in science and 8302: 8238: 6871: 6107: 5871: 5225: 4867: 4147: 2960: 7942: 6007: 5530: 5291: 5028: 4993: 4845: 4430: 3897: 3596: 2986: 2354:
The unit dBW is often used to denote a ratio for which the reference is 1 W, and similarly dBm for a
2195: 3617: 7790: 7661: 5975: 5912: 5516: 5431: 4977: 4963: 4637: 4609: 4034: 2166:
must hold to allow the power level difference to be equal to the root-power level difference from power
218: 159: 127: 3725:{\displaystyle L_{p}=20\log _{10}\!\left({\frac {p_{\text{rms}}}{p_{\text{ref}}}}\right)\,{\text{dB}},} 6282:(7th ed.). New York: The Institute of Electrical and Electronics Engineering. 2000. p. 288. 3644:. As sound pressure is a root-power quantity, the appropriate version of the unit definition is used: 1155:
The method of expressing a ratio as a level in decibels depends on whether the measured property is a
6618: 6169: 5922: 5198: 5171: 4599: 4587: 4575: 3637: 3600: 3061: 3033: 2964: 2057: 1943:
in the respective levels match under restricted conditions such as when the medium is linear and the
1880:{\displaystyle L_{G}=20\log _{10}\!\left({\frac {V_{\text{out}}}{V_{\text{in}}}}\right)\,{\text{dB}}} 1790: 35: 7598: 6668:
Nicholas P. Cheremisinoff (1996) Noise Control in Industry: A Practical Guide, Elsevier, 203 pp, p.
4182: 8223: 6900:
The Impact of A-weighting Sound Pressure Level Measurements during the Evaluation of Noise Exposure
6759: 6609:
I M Mills; B N Taylor; A J Thor (2001), "Definitions of the units radian, neper, bel and decibel",
6308: 5761:{\displaystyle {\sqrt {0.6}}\,{\text{V}}\,\approx 0.7746\,{\text{V}}\,\approx -2.218\,{\text{dBV}}} 5677: 5506: 4953: 4806: 3867: 3540: 3049: 2882: 2835: 1064: 56: 6898: 2834:
Should it be necessary to make the distinction, the number of decibels is written with additional
1152:. Thus, five one-thousandths of a bel would normally be written 0.05 dB, and not 5 mB. 8282: 7916: 7239: 7116: 6634: 6454: 6077: 6048: 5404:, this indicates the relative levels of noise or sideband power, compared with the carrier power. 5401: 4825: 4505: 3909: 3053: 1778: 1351:
must measure the same type of quantity, and have the same units before calculating the ratio. If
188: 151: 1117:
Two signals whose levels differ by one decibel have a power ratio of 10, which is approximately
276:, which justifies the use of the decibel for voltage ratios. In spite of their widespread use, 7621: 6519:
Thompson, A. and Taylor, B. N. sec 8.7, "Logarithmic quantities and units: level, neper, bel",
5138: 4654: 8261: 8147: 7935: 7854: 7641: 7526: 7509: 7473: 7416: 7293: 7194: 7167: 7073: 7046: 7017: 7011: 6990: 6984: 6963: 6957: 6936: 6827: 6793: 6776: 6742: 6698: 6580: 6555: 6400: 6333: 6283: 6206: 6202: 5932: 5837: 5557: 5502: 5308: 4949: 4793: 4623: 3856: 3633: 3589: 2878: 2199: 1188: 1078: 118:
The definition of the decibel originated in the measurement of transmission loss and power in
72: 7574: 7550: 7188: 7038: 6810: 6694: 6499: 6323: 7901: 7842: 7837: 7783: 6669: 6626: 6446: 6353: 6234: 6092: 5971: 5856: 5801: 5702: 5594: 5343: 4633: 4557: 4543: 4534: 4311: 4244: 4216: 3964: 3743: 3534: 2807: 2053: 1898: 1786: 103: 5925:) – for sound in air and other gases, relative to 20 μPa in air or 1 μPa in water 1793:
is constant. Taking voltage as an example, this leads to the equation for power gain level
8014: 6267: 5661: 5328: 5274: 4014: 3840:{\displaystyle L_{p}=10\log _{10}\!\left({\frac {I}{I_{\text{ref}}}}\right)\,{\text{dB}},} 3763: 1179: 7759: 7289: 7282: 5676:
represents an audio level measurement, typically in a telephone circuit, relative to the
4574:
Probably the most common usage of "decibels" in reference to sound level is dB SPL,
4302:{\displaystyle V={\sqrt {600\,\Omega \cdot 0.001\,{\text{W}}}}\approx 0.7746\,{\text{V}}} 7760:
Conversion of sound level units: dBSPL or dBA to sound pressure p and sound intensity J
6861:
C. S. Clay (1999), Underwater sound transmission and SI units, J Acoust Soc Am 106, 3047
6622: 6472: 6173: 8167: 8099: 7359: 7141: 6572: 6072: 6020: 5696:
of a signal compared with the maximum which a device can handle before clipping occurs.
5693: 5624:
of a signal (usually audio) compared with the maximum which a device can handle before
5435: 5043:
of a signal (usually audio) compared with the maximum which a device can handle before
5003: 4967: 4779: 4679:
as a measure of hearing loss. The reference level varies with frequency according to a
4487: 4467: 4191: 3908:
In electronics, the decibel is often used to express power or amplitude ratios (as for
3878: 3641: 3044: 147: 6540:. International Electrotechnical Commission. Part 3: Logarithmic quantities and units. 4976:
dB(isotropic circular) – the gain of an antenna compared to the gain of a theoretical
8276: 8228: 8152: 8089: 8079: 7321: 6638: 6195: 5379: 4672: 4038: 4003: 3937: 3860: 3851: 3585: 2893: 2045: 1916: 1135: 249:
for "standard magnitudes which combine by multiplication", to contrast with the name
6458: 6069:(Ldl), European and American standards for expressing noise level over an entire day 2048:
in which the power quantity is the product of two linearly related quantities (e.g.
8172: 8129: 8114: 8069: 8049: 7966: 7911: 7827: 6832: 6815: 6798: 6781: 6764: 6747: 6630: 6405: 6053: 5498: 5336: 4945: 4026: 3991: 3941: 3893: 6305:
Transmission Circuits for Telephonic Communication: Methods of analysis and design
3920:. One advantage is that the total decibel gain of a series of components (such as 6357: 4590:) – for sound in air and other gases, relative to 20 micropascals (μPa), or 8044: 7999: 7906: 7849: 7112: 6379:
Martin, W. H. (January 1929). "DeciBel—The New Name for the Transmission Unit".
6329: 5984: 5479: 5020: 4763: 4646: 4159: 4071: 3945: 3871: 3754: 3581: 281: 191: 155: 143: 135: 131: 123: 7715: 7333: 7224:
IEC 61672-1:2013 Electroacoustics - Sound Level meters - Part 1: Specifications
1020:
ISO 80000-3 describes definitions for quantities and units of space and time.
7600:
Reference Data for Engineers: Radio, Electronics, Computers and Communications
7497:
The use of the decibel and of relative levels in speechband telecommunications
7122: 5488: 5463: 4879: 4747: 4225: 4030: 4010: 3913: 2967:". Thus, units require special care in decibel operations. Take, for example, 2956: 2786:
A change in power ratio by a factor of 10 corresponds to a change in level of
2156:{\displaystyle {\frac {P_{2}}{P_{1}}}=\left({\frac {F_{2}}{F_{1}}}\right)^{2}} 199: 195: 4649:. According to standards from the International Electro-technical Committee ( 2853:. Similarly, an increase of 6.000 dB corresponds to the power ratio is 1191:
of the ratio of the measured quantity to reference value. Thus, the ratio of
8109: 8024: 7769: 6524: 6450: 6260: 6031: 5896: 5875: 5621: 5569: 5475: 5467: 5451: 5128:{\displaystyle L_{\text{ov}}=10\log _{10}\left({\frac {P}{P_{0}}}\right)\ ,} 5040: 4896: 4882: 4871: 4857: 4759: 4751: 4723: 4676: 4650: 3933: 3921: 3889: 3629: 3592: 2906: 2887: 2034:{\displaystyle {\frac {P(t)}{P_{0}}}=\left({\frac {F(t)}{F_{0}}}\right)^{2}} 1024: 206: 139: 119: 1211:, that ratio expressed in decibels, which is calculated using the formula: 260:(CIPM) considered a recommendation for the inclusion of the decibel in the 4844:. 1 joule = 1 watt second = 1 watt per hertz, so 3967:
voltage which delivers 1 mW (0 dBm) into a 600-ohm resistor, or
2885:. This allows one to clearly visualize huge changes of some quantity. See 1027:
defines the following quantities. The decibel (dB) is one-tenth of a bel:
178:(approximately 1.6 km) of standard telephone cable at a frequency of 7989: 7754: 7266: 7213:
Morfey, C. L. (2001). Dictionary of Acoustics. Academic Press, San Diego.
6650:
R. Hickling (1999), Noise Control and SI Units, J Acoust Soc Am 106, 3048
6082: 5540: 4916: 4423: 4203: 4050: 7775: 7722:
Logarithms, preferred numbers, decibel, neper, phon - naturally related!
6521:
Guide for the Use of the International System of Units (SI) 2008 Edition
4406:
Originally dBv, it was changed to dBu to avoid confusion with dBV. The
4310:(i.e. the voltage that would dissipate 1 mW into a 600 Ω load). An 3642:
common comparisons used to illustrate different levels of sound pressure
2944:
25 dB = 10 dB + 10 dB + 3 dB + 1 dB + 1 dB
221:. The bel is seldom used, as the decibel was the proposed working unit. 8177: 8104: 8034: 8029: 7979: 5470:
of a signal compared with the maximum which a device can handle before
4754:
of a signal compared with the maximum which a device can handle before
4232:, in order to reduce manufacturing costs relative to equipment using a 3917: 2049: 1782: 5515:
dB(isotropic circular) – the forward gain of an antenna compared to a
4512:. Consumer equipment typically uses a lower "nominal" signal level of 2776:{\displaystyle G=10^{\frac {3}{10}}\times 1=1.995\,26\ldots \approx 2} 8192: 8094: 8004: 7984: 7974: 6418:
Harrison, William H. (1931). "Standards for Transmission of Speech".
6011: 5831: 5553: 5474:
occurs. Full-scale may be defined as the power level of a full-scale
5304: 4758:
occurs. Full-scale may be defined as the power level of a full-scale
4163: 3995: 2995:(in W/Hz). Expressed in decibels, this ratio would be a subtraction ( 2215:
Conversion between units of level and a list of corresponding ratios
183: 17: 7385: 6523:, NIST Special Publication 811, 2nd printing (November 2008), SP811 241:
expressing the efficiency of different parts of the circuit ...
30:
This article is about the logarithmic unit. For use of this unit in
7717:
Logarithmen, Normzahlen, Dezibel, Neper, Phon - natürlich verwandt!
224:
The naming and early definition of the decibel is described in the
8207: 8202: 8187: 8064: 8059: 8054: 8039: 7994: 6087: 6035: 5965: 5961: 5957: 5953: 5949: 5945: 5879: 5526: 5421: 5411: 5389: 5369: 4875: 4841: 4689:
sometimes used to denote weighted noise level, commonly using the
4181: 2230: 1140: 1042: 31: 8182: 8124: 8119: 7880: 7875: 7236: 7164:
The IEEE Standard Dictionary of Electrical and Electronics terms
6112: 6102: 6019:
dB(m) – decibel relative to reciprocal of meter: measure of the
5861: 5822: 5806: 5705: 5655: 5599: 5575: 5457: 5268: 5034: 5002:
dB(m) – decibel relative to reciprocal of meter: measure of the
4906: 4741: 4729: 4562: 4539: 4247: 4221: 4199: 4049:
Photographers typically use an alternative base-2 log unit, the
273: 175: 92: 7931: 7779: 5195:. The level of a tone with a digital amplitude (peak value) of 2842:, about 0.24% different from exactly 2, and a voltage ratio of 2596:, illustrating the consequence from the definitions above that 1908:
is the rms input voltage. A similar formula holds for current.
1416:
Rearranging the above equation gives the following formula for
8157: 8084: 8074: 7865: 7821: 7437:"The dBμ vs. dBu Mystery: Signal Strength vs. Field Strength?" 6897:
Richard L. St. Pierre, Jr. and Daniel J. Maguire (July 2004),
5563: 5395: 5323: 4851: 4819: 4717: 4662: 4542:
relative to 1 millivolt across 75 Ω. Widely used in
4195: 4187: 4033:
where response voltage is linear in intensity. Thus, a camera
3999: 3960: 3953: 1781:, dissipated power is typically proportional to the square of 79:
differ by one decibel have a power ratio of 10 (approximately
7043:
Image sensors and signal processing for digital still cameras
4992:
dB(m) – decibel relative to one square meter: measure of the
4878:. The unit is often used to specify the signal strength of a 4805:
dB(m) – decibel relative to one square meter: measure of the
174:(MSC). 1 MSC corresponded to the loss of power over one 7552:
Comprehensive Glossary of Telecom Abbreviations and Acronyms
6933:
Subscriber Loop Signaling and Transmission Handbook – Analog
6878:. Centers for Disease Control and Prevention. 7 October 2019 6426:. National Bureau of Standards, U. S. Govt. Printing Office. 5970:
These symbols are often used to denote the use of different
4632:
These symbols are often used to denote the use of different
4162:
sound pressure level). The suffix is often connected with a
3959:
In professional audio specifications, a popular unit is the
27:
Logarithmic unit expressing the ratio of physical quantities
7927: 6280:
IEEE Standard 100: a dictionary of IEEE standards and terms
6178:
the decibel represents a reduction in power of 1.258 times
6097: 4598:, approximately the quietest sound a human can hear. For 1767:{\displaystyle F=10^{\frac {L_{F}}{20\,{\text{dB}}}}F_{0}} 1495:{\displaystyle P=10^{\frac {L_{P}}{10\,{\text{dB}}}}P_{0}} 7226:. Geneva: International Electrotechnical Committee. 2013. 7069:
The Audio Expert: Everything You Need to Know About Audio
5580:
Power in dBm measured at a zero transmission level point.
5290:
is used for this purpose on international circuits. See
5505:, which uniformly distributes energy in all directions. 4952:, which uniformly distributes energy in all directions. 2838:. 3.000 dB corresponds to a power ratio of 10, or 6201:(Second ed.). Holt, Rinehart and Winston. p.  4053:, to describe light intensity ratios or dynamic range. 1134:
The bel is rarely used either without a prefix or with
6777:
Visual Perception: Physiology, Psychology, and Ecology
6536:"Letter symbols to be used in electrical technology". 5168:, for a rectangular signal with the maximum amplitude 1124:, and an amplitude (root-power quantity) ratio of 10 ( 1077:, thereby relating all of the units as nondimensional 5715: 5228: 5201: 5174: 5141: 5053: 4490: 4470: 4433: 4320: 4257: 3775: 3653: 3543: 3205: 3073: 2946:
With an input of 1 watt, the output is approximately
2726: 2624: 2498: 2380: 2086: 1956: 1811: 1717: 1536: 1445: 1220: 253:
for "standard magnitudes which combine by addition".
7662:"en:users:documentation:iw [Linux Wireless]" 6732:, Routledge, 12 November 2013, 400 pages, p. 13 6500:"Letter symbols to be used in electrical technology" 3573:, since logarithmic division is linear subtraction. 3537:
is obtained from the logarithmic sum by subtracting
2948:
1 W × 10 × 10 × 2 × 1.26 × 1.26 ≈ 317.5 W
1067:
when the root-power quantity changes by a factor of
126:
in the United States. The bel was named in honor of
8216: 8138: 8013: 7965: 5317:dB(K) – decibels relative to 1 K. — 4532:
Defined by Recommendation ITU-R V.574.; dBmV: dB(mV
7755:What is a decibel? With sound files and animations 7528:Satellite Communication: Concepts And Applications 7281: 6983:Stephen J. Sangwine and Robin E. N. Horne (1998). 6194: 5760: 5509:of the EM field is assumed unless noted otherwise. 5251: 5214: 5187: 5160: 5127: 4956:of the EM field is assumed unless noted otherwise. 4496: 4476: 4455: 4398: 4301: 3839: 3724: 3565: 3522: 3190: 2775: 2706: 2582: 2468: 2155: 2033: 1879: 1766: 1697: 1494: 1329: 277: 198:per mile" (approximately corresponding to 19  6437:Horton, J. W. (1954). "The bewildering decibel". 5529:. 1 joule = 1 watt second = 1 watt per hertz, so 4653:) and the American National Standards Institute, 3802: 3680: 2198:and the associated root-power quantities via the 1838: 1601: 1553: 1295: 1247: 7016:. Cambridge University Press. pp. 102–103. 6760:Introduction to Understandable Physics, Volume 2 5640:relative to the maximum value of the peak power. 4834:relative to the maximum value of the peak power. 4612:– relative to 10 W/m, which is roughly the 3879:Sound pressure § Examples of sound pressure 1935:Relationship between power and root-power levels 258:International Committee for Weights and Measures 7765:OSHA Regulations on Occupational Noise Exposure 7680:"Is your WiFi AP Missing Channels 12 & 13?" 7240:S1.4-19823 Specification for Sound Level Meters 6478:. Consultative Committee for Units. Section 3. 3753:is the standard reference sound pressure of 20 2963:, thus being "of unacceptable form for use in 230: 6962:. McGraw-Hill Professional. pp. 123–126. 4122:is the value of the reference quantity, e.g., 4002:(referenced to 1 mW), is launched into a 2790:. A change in power ratio by a factor of 2 or 2618:(one milliwatt) is obtained with the formula: 284:or dBV) are not recognized by the IEC or ISO. 270:International Organization for Standardization 7943: 7791: 7475:EW 102: A Second Course in Electronic Warfare 6494: 6492: 5905:sometimes used to denote weighted noise level 4734:Power in dBm (described above) measured at a 4314:voltage of 1 V therefore corresponds to 4186:A schematic showing the relationship between 3469: 3423: 3363: 3317: 3165: 3119: 217:, in honor of the telecommunications pioneer 67:). It expresses the ratio of two values of a 8: 7118:Creation of the dBu standard level reference 7010:Francis T. S. Yu and Xiangyang Yang (1997). 5809:relative to 1 volt, regardless of impedance. 5686:dB(m) – decibel relative to one square meter 5634:relative to the peak to peak sound pressure. 4698:relative to the peak to peak sound pressure. 3043:if two machines each individually produce a 8234:Historical definitions of the SI base units 6515: 6513: 6511: 6509: 5842:dB(Z) – decibel relative to Z = 1 mm⋅m 2901:Representation of multiplication operations 83:) or root-power ratio of 10 (approximately 7950: 7936: 7928: 7798: 7784: 7776: 6217:a pressure ratio of 1.122 equals + 1.0 dB 6038:kernel and the regulatory domain sections. 4074:standard recommends the following format: 3060:Addition on a logarithmic scale is called 1183:quantities, a ratio can be expressed as a 291: 7870: 7597:Mac E. Van Valkenburg (19 October 2001). 5753: 5752: 5742: 5737: 5736: 5729: 5724: 5723: 5716: 5714: 5244: 5227: 5206: 5200: 5179: 5173: 5146: 5140: 5114: 5096: 5087: 5074: 5058: 5052: 4885:at a receiving site (the signal measured 4489: 4469: 4440: 4432: 4388: 4387: 4370: 4363: 4355: 4350: 4344: 4331: 4319: 4294: 4293: 4280: 4279: 4269: 4264: 4256: 3829: 3828: 3816: 3807: 3796: 3780: 3774: 3714: 3713: 3701: 3691: 3685: 3674: 3658: 3652: 3620:), making the dB scale a useful measure. 3551: 3542: 3511: 3510: 3499: 3498: 3481: 3468: 3467: 3457: 3453: 3436: 3432: 3422: 3421: 3412: 3382: 3381: 3368: 3362: 3361: 3351: 3347: 3330: 3326: 3316: 3315: 3301: 3273: 3263: 3262: 3251: 3250: 3214: 3206: 3204: 3183: 3182: 3171: 3170: 3164: 3163: 3153: 3149: 3132: 3128: 3118: 3117: 3108: 3090: 3089: 3078: 3077: 3072: 2760: 2737: 2725: 2699: 2698: 2687: 2686: 2674: 2664: 2658: 2645: 2629: 2623: 2575: 2574: 2563: 2562: 2550: 2549: 2539: 2538: 2532: 2519: 2503: 2497: 2461: 2460: 2449: 2448: 2436: 2435: 2425: 2424: 2420: 2414: 2401: 2385: 2379: 2147: 2135: 2125: 2119: 2103: 2093: 2087: 2085: 2025: 2013: 1993: 1977: 1957: 1955: 1872: 1871: 1859: 1849: 1843: 1832: 1816: 1810: 1758: 1745: 1744: 1734: 1728: 1716: 1690: 1689: 1677: 1668: 1655: 1640: 1639: 1627: 1622: 1612: 1606: 1595: 1580: 1579: 1567: 1558: 1541: 1535: 1486: 1473: 1472: 1462: 1456: 1444: 1322: 1321: 1309: 1300: 1289: 1274: 1273: 1261: 1252: 1234: 1225: 1219: 266:International Electrotechnical Commission 7360:"RIDGE Radar Frequently Asked Questions" 6229: 6227: 6225: 6197:Fundamentals of Hearing: An Introduction 6166:Physical Properties of Polymers Handbook 6000:dB(Hz) – bandwidth relative to one hertz 4948:compared with the gain of a theoretical 2213: 1187:in decibels by evaluating ten times the 7885: 6408:, Robert J. Chapuis, Amos E. Joel, 2003 6188: 6186: 6153: 6124: 4814:Radio power, energy, and field strength 2077:need not be related), or equivalently, 1512:Power, root-power, and field quantities 1166:Power, root-power, and field quantities 1144:; it is preferred, for example, to use 7646:: CS1 maint: archived copy as title ( 7639: 7190:Audio postproduction for digital video 6159: 6157: 5974:, used to approximate the human ear's 5775:Defined by Recommendation ITU-R V.574. 5586:Defined by Recommendation ITU-R V.574. 5355:List of suffixes in alphabetical order 5252:{\displaystyle L=-3.01\ {\text{dBov}}} 4636:, used to approximate the human ear's 3028:Representation of addition operations 1708:The formula may be rearranged to give 994:An example scale showing power ratios 7735:from the original on 18 December 2016 6913:from the original on 22 December 2015 4025:In connection with video and digital 2362:Calculating the ratio in decibels of 300: 297: 7: 6986:The Colour Image Processing Handbook 6959:Fiber optic installer's field manual 6552:Fiber Optics: Physics and Technology 6485:from the original on 6 October 2014. 5602:relative to 1 millivolt across 75 Ω. 5430:dB(dipole) – the forward gain of an 5346:system noise equivalent temperature 5303: – decibels relative to 1  4524:is common in professional equipment. 4456:{\displaystyle V={\sqrt {R\cdot P}}} 2981:(in hertz), involving carrier power 1202:(reference power) is represented by 7284:Understanding Telephone Electronics 7013:Introduction to optical engineering 6872:"Loud Noise Can Cause Hearing Loss" 6579:(3rd ed.). Wiley. p. 63. 6538:International Standard CEI-IEC 27-3 6322:Davis, Don; Davis, Carolyn (1997). 4966:compared with the gain a half-wave 4657:, the preferred usage is to write L 3746:of the measured sound pressure and 2716:The power ratio corresponding to a 1927:is deprecated by that standard and 7714:Paulin, Eugen (1 September 2007). 7525:K. N. Raja Rao (31 January 2013). 7366:from the original on 31 March 2019 7340:from the original on 8 August 2019 5321:decibels per kelvin: Used for the 4915:dB(kW) – power relative to 1  4895:dB(fW) – power relative to 1  4856:dB(mW) – power relative to 1  4722:dB(mW) – power relative to 1  4270: 3757:in air or 1 micropascal in water. 1177:When referring to measurements of 25: 7628:from the original on 3 March 2016 7576:The Digital Satellite TV Handbook 7392:from the original on 10 June 2019 6303:Johnson, Kenneth Simonds (1944). 4970:. 0 dBd = 2.15 dBi 4905:dB(W) – power relative to 1  2810:. More precisely, the change is ± 1931:is used throughout this article. 1059:. The neper is the change in the 162:are often expressed in decibels. 122:of the early 20th century in the 8257: 8256: 7441:radio-timetraveller.blogspot.com 7140:. Deltamedia.com. Archived from 6401:100 Years of Telephone Switching 4009:In spectrometry and optics, the 3628:The decibel is commonly used in 1007:, and dB equivalents 10 log 7772:(RF signal and field strengths) 6093:One-third octave § Base 10 5501:compared with the hypothetical 5215:{\displaystyle x_{\text{over}}} 5188:{\displaystyle x_{\text{over}}} 3979: 2860:, about 0.5% different from 4. 2846:, 0.12% different from exactly 1084:of root-power-quantity ratios, 8298:Telecommunications engineering 8244:System of units of measurement 6989:. Springer. pp. 127–130. 5478:or alternatively a full-scale 5135:with the maximum signal power 5119: 5111: 5025:carrier-to-noise-density ratio 4762:or alternatively a full-scale 4057:Suffixes and reference values 3232: 3220: 2969:carrier-to-noise-density ratio 2005: 1999: 1969: 1963: 1915:is introduced by ISO Standard 91:the reference value of 1  1: 7809: 7166:(6th ed.). IEEE. 1996 . 7045:. CRC Press. pp. 79–83. 7041:. In Junichi Nakamura (ed.). 6828:Fitting The Task To The Human 6382:Bell System Technical Journal 6067:day-night average sound level 6059:Day–evening–night noise level 6030:mB(mW) – power relative to 1 6006:dB(K) – decibels relative to 5899:as a measure of hearing loss. 5568:dB(mW) – power relative to 1 5539:dB(kW) – power relative to 1 5450:dB(fW) – power relative to 1 4736:zero transmission level point 4665:, used in telecommunications. 3584:constants, in topics such as 3566:{\displaystyle 10\log _{10}2} 2720:change in level is given by: 1506:Root-power (field) quantities 262:International System of Units 228:Standard's Yearbook of 1931: 7832: 7336:. National Weather Service. 7263:"Turbine Sound Measurements" 7072:. Focal Press. p. 107. 6935:(1st ed.). IEEE Press. 6240:/ dBm / dBu / dBV calculator 5895:dB hearing level is used in 5887:Suffixes preceded by a space 5821:dB(W) – power relative to 1 5497:dB(isotropic) – the forward 5438:. 0 dBd = 2.15 dBi 4962:dB(dipole) – the gain of an 4713:See also dBV and dBu above. 4134: = 20 dB or 4017:is equivalent to −1 B. 2594:(31.62 V / 1 V) ≈ 1 kW / 1 W 1364:in the above equation, then 96: 69:power or root-power quantity 8293:Radio frequency propagation 7386:"Definition at Everything2" 7193:. Focal Press. p. 25. 6730:Acoustics and Noise Control 5940:Suffixes within parentheses 5023:calculations. Also used in 4115:is the quantity symbol and 3963:. This is relative to the 3595:, are often expressed as a 207:Bell Telephone Laboratories 8319: 7860: 7415:. Newnes. pp. 45–46. 7413:RF Components and Circuits 7242:, 2.3 Sound Level, p. 2–3. 6931:Reeve, William D. (1992). 6168:. Springer. p. 1025. 5434:compared with a half-wave 4840:energy relative to 1  4704:G‑weighted spectrum 4614:threshold of human hearing 4146:= 20 dB for the 3971:1 mW×600 Ω 3876: 3850:The human ear has a large 3031: 1509: 29: 8252: 7894: 7817: 7280:Bigelow, Stephen (2001). 7039:"Basics of Image Sensors" 7037:Junichi Nakamura (2006). 6811:Foundations of Perception 5915:– relative to 10 W/m 5400:relative to carrier – in 5161:{\displaystyle P_{0}=1.0} 5027:(not to be confused with 4824:relative to carrier – in 4691:ITU-R 468 noise weighting 4198:(the power dissipated as 4021:Video and digital imaging 2610:The ratio in decibels of 2478:The ratio in decibels of 993: 294: 99:" (e.g., "20 dBV"). 8198:minute and second of arc 6743:Sensation and Perception 6631:10.1088/0026-1394/38/4/8 6362:Bell Laboratories Record 6358:"'TU' becomes 'Decibel'" 6325:Sound system engineering 5935:– relative to 10 W. 5864:relative to 1 microvolt. 5533:can be expressed in dBJ. 5333:satellite communications 4848:can be expressed in dBJ. 4681:minimum audibility curve 4626:– relative to 10 W. 256:In April 2003, the 59:equal to one tenth of a 40:Decibel (disambiguation) 8239:2019 revision of the SI 6451:10.1109/EE.1954.6438830 6368:(4). AT&T: 137–139. 6164:Mark, James E. (2007). 6108:Richter magnitude scale 5872:electric field strength 5552:– decibels relative to 4868:electric field strength 4148:electric field strength 3994:, if a known amount of 3898:psophometric weightings 3888:The decibel is used in 1146:hundredths of a decibel 172:miles of standard cable 134:, most prominently for 106:. That is, a change in 6439:Electrical Engineering 6193:Yost, William (1985). 5867:dBμV/m, dBuV/m, or dBμ 5762: 5531:power spectral density 5292:Psophometric weighting 5253: 5216: 5189: 5162: 5129: 5029:carrier-to-noise ratio 4994:antenna effective area 4863:dBμV/m, dBuV/m, or dBμ 4846:power spectral density 4498: 4484:is the resistance and 4478: 4457: 4418:comes from the volume 4400: 4303: 4207: 3841: 3726: 3567: 3524: 3192: 3058: 2987:power spectral density 2873:Reporting large ratios 2777: 2708: 2584: 2470: 2196:power spectral density 2157: 2035: 1901:(rms) output voltage, 1881: 1768: 1699: 1496: 1331: 243: 160:signal-to-noise ratios 150:. In electronics, the 104:logarithm with base 10 95:, a common suffix is " 38:. For other uses, see 7770:Working with Decibels 7495:ITU-T Rec. G.100.1, " 7411:Carr, Joseph (2002). 7066:Winer, Ethan (2013). 6956:Chomycz, Bob (2000). 6577:Microwave Engineering 5913:sound intensity level 5763: 5525:energy relative to 1 5360:Unpunctuated suffixes 5254: 5217: 5190: 5163: 5130: 4889:is reported in dBμV). 4887:at the antenna output 4610:sound intensity level 4499: 4479: 4458: 4401: 4304: 4185: 4035:signal-to-noise ratio 3877:Further information: 3842: 3727: 3568: 3525: 3193: 3041: 3032:Further information: 2985:(in watts) and noise 2778: 2709: 2585: 2471: 2158: 2036: 1882: 1769: 1700: 1497: 1332: 219:Alexander Graham Bell 128:Alexander Graham Bell 8140:Other accepted units 7269:on 12 December 2010. 6691:Dimensional Analysis 5923:sound pressure level 5834:relative to 1 W·m·Hz 5713: 5517:circularly polarized 5226: 5199: 5172: 5139: 5051: 4978:circularly polarized 4944:dB(isotropic) – the 4936:Antenna measurements 4588:sound pressure level 4576:sound pressure level 4488: 4468: 4431: 4318: 4255: 3773: 3651: 3638:sound pressure level 3601:dimensional analysis 3541: 3203: 3071: 3062:logarithmic addition 3034:Logarithmic addition 2965:dimensional analysis 2724: 2622: 2496: 2378: 2084: 1954: 1809: 1715: 1534: 1443: 1218: 1195:(measured power) to 75:. Two signals whose 36:Sound pressure level 8224:Conversion of units 7666:wireless.kernel.org 6794:Exercise Psychology 6623:2001Metro..38..353M 6309:D. Van Nostrand Co. 6174:2007ppph.book.....M 5678:circuit noise level 5620:dB(overload) – the 5507:Linear polarization 5039:dB(overload) – the 4954:Linear polarization 4870:relative to 1  4807:radar cross section 3912:) in preference to 3868:frequency weighting 3050:logarithmic average 2883:scientific notation 2836:significant figures 2808:change of 3 dB 2806:is approximately a 2343:10 ≈ 3.162 28 2216: 1919:as a substitute of 1913:root-power quantity 1779:electrical circuits 1632: 1161:root-power quantity 1065:root-power quantity 998:, amplitude ratios 57:unit of measurement 8017:with special names 7917:telecommunications 7443:. 24 February 2015 7288:. Newnes. p.  7125:on 30 October 2021 6763:, p. SA19-PA9, at 6420:Standards Yearbook 6266:2016-06-03 at the 6236:Utilities : V 6078:Decade (log scale) 6049:Apparent magnitude 5758: 5556:: Used to express 5499:gain of an antenna 5402:telecommunications 5307:; used to express 5249: 5212: 5185: 5158: 5125: 5011:Other measurements 4946:gain of an antenna 4826:telecommunications 4506:professional audio 4494: 4474: 4453: 4396: 4299: 4236:line-level signal. 4208: 4202:by the 600 Ω 3837: 3722: 3588:communication and 3563: 3520: 3518: 3188: 3054:arithmetic average 2773: 2704: 2580: 2466: 2366:(one kilowatt, or 2214: 2153: 2031: 1877: 1764: 1695: 1618: 1492: 1327: 34:measurements, see 8288:Audio electronics 8270: 8269: 8148:astronomical unit 7925: 7924: 7549:Ali Akbar Arabi. 7200:978-1-57820-116-7 7187:Jay Rose (2002). 7173:978-1-55937-833-8 7079:978-0-240-82100-9 7052:978-0-8493-3545-7 7023:978-0-521-57493-8 6996:978-0-412-80620-9 6969:978-0-07-135604-6 6718:. Springer. 2010. 6697:, Springer, 2011 6586:978-0-471-44878-5 6554:, Springer, 2010 6473:"Meeting minutes" 6356:(December 1928). 6354:Hartley, R. V. L. 6339:978-0-240-80305-0 6289:978-0-7381-2601-2 6212:978-0-12-772690-8 5972:weighting filters 5933:sound power level 5756: 5740: 5727: 5721: 5558:noise temperature 5503:isotropic antenna 5309:noise temperature 5247: 5243: 5209: 5182: 5117: 5110: 5102: 5061: 4950:isotropic antenna 4709:Audio electronics 4634:weighting filters 4629:dBA, dBB, and dBC 4624:sound power level 4504:is the power. In 4497:{\displaystyle P} 4477:{\displaystyle R} 4451: 4391: 4375: 4368: 4358: 4297: 4285: 4283: 3857:logarithmic scale 3832: 3822: 3819: 3717: 3707: 3704: 3694: 3634:sound power level 3618:Weber–Fechner law 3590:radio propagation 3514: 3502: 3385: 3266: 3254: 3217: 3186: 3174: 3093: 3081: 2879:logarithmic scale 2745: 2702: 2690: 2680: 2677: 2667: 2578: 2566: 2556: 2553: 2542: 2464: 2452: 2442: 2439: 2428: 2358:reference point. 2347: 2346: 2238:Root-power ratio 2200:Fourier transform 2141: 2109: 2019: 1983: 1875: 1865: 1862: 1852: 1751: 1748: 1693: 1683: 1643: 1633: 1583: 1573: 1479: 1476: 1325: 1315: 1277: 1267: 1242: 1189:base-10 logarithm 1031:. The bel (B) is 1023:The IEC Standard 1018: 1017: 211:Transmission Unit 73:logarithmic scale 16:(Redirected from 8310: 8260: 8259: 7952: 7945: 7938: 7929: 7902:logarithmic unit 7800: 7793: 7786: 7777: 7744: 7742: 7740: 7734: 7727: 7710: 7688: 7687: 7676: 7670: 7669: 7658: 7652: 7651: 7645: 7637: 7635: 7633: 7618: 7612: 7611: 7609: 7607: 7594: 7588: 7587: 7585: 7583: 7570: 7564: 7563: 7561: 7559: 7546: 7540: 7539: 7537: 7535: 7522: 7516: 7506: 7500: 7493: 7487: 7486: 7484: 7482: 7469: 7463: 7459: 7453: 7452: 7450: 7448: 7433: 7427: 7426: 7408: 7402: 7401: 7399: 7397: 7382: 7376: 7375: 7373: 7371: 7356: 7350: 7349: 7347: 7345: 7330: 7324: 7319: 7313: 7310: 7304: 7303: 7287: 7277: 7271: 7270: 7265:. Archived from 7259: 7253: 7249: 7243: 7234: 7228: 7227: 7220: 7214: 7211: 7205: 7204: 7184: 7178: 7177: 7160: 7154: 7153: 7151: 7149: 7136:deltamedia.com. 7133: 7127: 7126: 7121:, archived from 7109: 7103: 7102: 7090: 7084: 7083: 7063: 7057: 7056: 7034: 7028: 7027: 7007: 7001: 7000: 6980: 6974: 6973: 6953: 6947: 6946: 6928: 6922: 6921: 6920: 6918: 6912: 6905: 6894: 6888: 6887: 6885: 6883: 6868: 6862: 6859: 6853: 6850: 6844: 6841: 6835: 6824: 6818: 6807: 6801: 6790: 6784: 6773: 6767: 6756: 6750: 6739: 6733: 6726: 6720: 6719: 6712: 6706: 6689:J. C. Gibbings, 6687: 6681: 6678: 6672: 6666: 6660: 6657: 6651: 6648: 6642: 6641: 6606: 6600: 6599:IEC 60027-3:2002 6597: 6591: 6590: 6569: 6563: 6550:Fedor Mitschke, 6548: 6542: 6541: 6533: 6527: 6517: 6504: 6503: 6496: 6487: 6486: 6484: 6477: 6469: 6463: 6462: 6434: 6428: 6427: 6415: 6409: 6397: 6391: 6390: 6376: 6370: 6369: 6350: 6344: 6343: 6328:(2nd ed.). 6319: 6313: 6312: 6300: 6294: 6293: 6276: 6270: 6258: 6252: 6251: 6250: 6248: 6243:, Analog Devices 6231: 6220: 6219: 6200: 6190: 6181: 6180: 6161: 6141: 6138: 6132: 6129: 5832:spectral density 5768: 5767: 5765: 5764: 5759: 5757: 5754: 5741: 5738: 5728: 5725: 5722: 5717: 5692:dB(true peak) – 5258: 5256: 5255: 5250: 5248: 5245: 5241: 5221: 5219: 5218: 5213: 5211: 5210: 5207: 5194: 5192: 5191: 5186: 5184: 5183: 5180: 5167: 5165: 5164: 5159: 5151: 5150: 5134: 5132: 5131: 5126: 5118: 5115: 5108: 5107: 5103: 5101: 5100: 5088: 5079: 5078: 5063: 5062: 5059: 4778:dB(true peak) – 4597: 4595: 4544:cable television 4523: 4519: 4515: 4511: 4503: 4501: 4500: 4495: 4483: 4481: 4480: 4475: 4463: 4462: 4460: 4459: 4454: 4452: 4441: 4405: 4403: 4402: 4397: 4392: 4389: 4380: 4376: 4374: 4369: 4364: 4361: 4360: 4359: 4356: 4345: 4336: 4335: 4309: 4308: 4306: 4305: 4300: 4298: 4295: 4286: 4284: 4281: 4265: 4235: 4231: 4170:List of suffixes 4145: 4133: 4110: 4092: 4013:used to measure 3973: 3972: 3965:root mean square 3944:, etc.) using a 3846: 3844: 3843: 3838: 3833: 3830: 3827: 3823: 3821: 3820: 3817: 3808: 3801: 3800: 3785: 3784: 3744:root mean square 3731: 3729: 3728: 3723: 3718: 3715: 3712: 3708: 3706: 3705: 3702: 3696: 3695: 3692: 3686: 3679: 3678: 3663: 3662: 3572: 3570: 3569: 3564: 3556: 3555: 3535:logarithmic mean 3529: 3527: 3526: 3521: 3519: 3515: 3512: 3503: 3500: 3497: 3493: 3486: 3485: 3473: 3472: 3466: 3465: 3461: 3445: 3444: 3440: 3427: 3426: 3417: 3416: 3390: 3386: 3383: 3380: 3376: 3372: 3367: 3366: 3360: 3359: 3355: 3339: 3338: 3334: 3321: 3320: 3306: 3305: 3284: 3277: 3272: 3268: 3267: 3264: 3255: 3252: 3219: 3218: 3215: 3197: 3195: 3194: 3189: 3187: 3184: 3175: 3172: 3169: 3168: 3162: 3161: 3157: 3141: 3140: 3136: 3123: 3122: 3113: 3112: 3094: 3091: 3082: 3079: 2951:instrumentation. 2924: 2859: 2856: 2852: 2851: 2845: 2841: 2830: 2826: 2823: 2821: 2820: 2813: 2805: 2803: 2802: 2799: 2796: 2789: 2782: 2780: 2779: 2774: 2747: 2746: 2738: 2719: 2713: 2711: 2710: 2705: 2703: 2700: 2691: 2688: 2685: 2681: 2679: 2678: 2675: 2669: 2668: 2665: 2659: 2650: 2649: 2634: 2633: 2617: 2613: 2595: 2589: 2587: 2586: 2581: 2579: 2576: 2567: 2564: 2561: 2557: 2555: 2554: 2551: 2544: 2543: 2540: 2533: 2524: 2523: 2508: 2507: 2491: 2487: 2485: 2484: 2475: 2473: 2472: 2467: 2465: 2462: 2453: 2450: 2447: 2443: 2441: 2440: 2437: 2430: 2429: 2426: 2415: 2406: 2405: 2390: 2389: 2373: 2369: 2365: 2357: 2323: 2322: 2311: 2310: 2298: 2297: 2289: 2288: 2276: 2275: 2267: 2266: 2257: 2256: 2217: 2162: 2160: 2159: 2154: 2152: 2151: 2146: 2142: 2140: 2139: 2130: 2129: 2120: 2110: 2108: 2107: 2098: 2097: 2088: 2040: 2038: 2037: 2032: 2030: 2029: 2024: 2020: 2018: 2017: 2008: 1994: 1984: 1982: 1981: 1972: 1958: 1899:root-mean-square 1886: 1884: 1883: 1878: 1876: 1873: 1870: 1866: 1864: 1863: 1860: 1854: 1853: 1850: 1844: 1837: 1836: 1821: 1820: 1773: 1771: 1770: 1765: 1763: 1762: 1753: 1752: 1750: 1749: 1746: 1739: 1738: 1729: 1704: 1702: 1701: 1696: 1694: 1691: 1688: 1684: 1682: 1681: 1669: 1660: 1659: 1644: 1641: 1638: 1634: 1631: 1626: 1617: 1616: 1607: 1600: 1599: 1584: 1581: 1578: 1574: 1572: 1571: 1559: 1546: 1545: 1501: 1499: 1498: 1493: 1491: 1490: 1481: 1480: 1478: 1477: 1474: 1467: 1466: 1457: 1393:is positive; if 1377:is greater than 1363: 1336: 1334: 1333: 1328: 1326: 1323: 1320: 1316: 1314: 1313: 1301: 1294: 1293: 1278: 1275: 1272: 1268: 1266: 1265: 1253: 1243: 1235: 1230: 1229: 1173:Power quantities 1136:SI unit prefixes 1130: 1129: 1123: 1122: 1113: 1112: 1103: 1101: 1095: 1093: 1087: 1076: 1075:1 Np = ln(e) = 1 1058: 1056: 1055: 1051: 1040: 1039: 1035: 1030: 1006: 1005: 989: 988: 978: 977: 974: 971: 956: 955: 952: 942: 941: 938: 923: 922: 912: 911: 908: 893: 892: 889: 879: 878: 875: 854: 853: 838: 837: 827: 826: 805: 804: 789: 788: 750: 749: 728: 726: 725: 722: 719: 707: 705: 704: 701: 698: 681: 680: 679: 677: 676: 673: 670: 655: 653: 652: 649: 646: 580: 579: 501: 500: 481: 480: 460: 459: 445: 444: 435: 434: 431: 417: 416: 407: 406: 403: 389: 388: 379: 378: 375: 361: 360: 351: 350: 347: 344: 330: 329: 320: 319: 316: 313: 301:Amplitude ratio 292: 181: 158:of signals, and 86: 82: 55:) is a relative 21: 8318: 8317: 8313: 8312: 8311: 8309: 8308: 8307: 8273: 8272: 8271: 8266: 8248: 8229:Metric prefixes 8212: 8134: 8016: 8009: 7961: 7956: 7926: 7921: 7890: 7813: 7804: 7751: 7738: 7736: 7732: 7725: 7713: 7703:VDI-Zeitschrift 7700: 7697: 7695:Further reading 7692: 7691: 7678: 7677: 7673: 7660: 7659: 7655: 7638: 7631: 7629: 7622:"Archived copy" 7620: 7619: 7615: 7605: 7603: 7596: 7595: 7591: 7581: 7579: 7572: 7571: 7567: 7557: 7555: 7548: 7547: 7543: 7533: 7531: 7524: 7523: 7519: 7507: 7503: 7494: 7490: 7480: 7478: 7471: 7470: 7466: 7460: 7456: 7446: 7444: 7435: 7434: 7430: 7423: 7410: 7409: 7405: 7395: 7393: 7384: 7383: 7379: 7369: 7367: 7358: 7357: 7353: 7343: 7341: 7334:"Glossary: D's" 7332: 7331: 7327: 7320: 7316: 7311: 7307: 7300: 7279: 7278: 7274: 7261: 7260: 7256: 7250: 7246: 7235: 7231: 7222: 7221: 7217: 7212: 7208: 7201: 7186: 7185: 7181: 7174: 7162: 7161: 7157: 7147: 7145: 7144:on 20 June 2013 7135: 7134: 7130: 7111: 7110: 7106: 7092: 7091: 7087: 7080: 7065: 7064: 7060: 7053: 7036: 7035: 7031: 7024: 7009: 7008: 7004: 6997: 6982: 6981: 6977: 6970: 6955: 6954: 6950: 6943: 6930: 6929: 6925: 6916: 6914: 6910: 6903: 6896: 6895: 6891: 6881: 6879: 6870: 6869: 6865: 6860: 6856: 6851: 6847: 6842: 6838: 6825: 6821: 6808: 6804: 6791: 6787: 6774: 6770: 6757: 6753: 6740: 6736: 6727: 6723: 6714: 6713: 6709: 6688: 6684: 6679: 6675: 6667: 6663: 6658: 6654: 6649: 6645: 6608: 6607: 6603: 6598: 6594: 6587: 6573:Pozar, David M. 6571: 6570: 6566: 6549: 6545: 6535: 6534: 6530: 6518: 6507: 6498: 6497: 6490: 6482: 6475: 6471: 6470: 6466: 6436: 6435: 6431: 6417: 6416: 6412: 6398: 6394: 6378: 6377: 6373: 6352: 6351: 6347: 6340: 6321: 6320: 6316: 6302: 6301: 6297: 6290: 6278: 6277: 6273: 6268:Wayback Machine 6259: 6255: 6246: 6244: 6239: 6233: 6232: 6223: 6213: 6192: 6191: 6184: 6163: 6162: 6155: 6150: 6145: 6144: 6139: 6135: 6130: 6126: 6121: 6064: 6045: 5994: 5982: 5942: 5889: 5859: 5804: 5711: 5710: 5709: 5662:reference noise 5597: 5362: 5357: 5335:, relating the 5329:figure of merit 5275:reference noise 5224: 5223: 5202: 5197: 5196: 5175: 5170: 5169: 5142: 5137: 5136: 5092: 5083: 5070: 5054: 5049: 5048: 5013: 4938: 4816: 4790: 4711: 4660: 4644: 4593: 4591: 4572: 4560: 4537: 4521: 4517: 4513: 4509: 4486: 4485: 4466: 4465: 4429: 4428: 4427: 4362: 4351: 4346: 4340: 4327: 4316: 4315: 4253: 4252: 4251: 4233: 4229: 4219: 4177: 4172: 4144: 4135: 4131: 4123: 4121: 4109: 4108: 4094: 4090: 4083: 4075: 4059: 4023: 4015:optical density 3988: 3977: 3970: 3968: 3906: 3886: 3881: 3812: 3803: 3792: 3776: 3771: 3770: 3764:Sound intensity 3752: 3741: 3697: 3687: 3681: 3670: 3654: 3649: 3648: 3626: 3614: 3609: 3579: 3547: 3539: 3538: 3517: 3516: 3477: 3449: 3428: 3408: 3407: 3403: 3388: 3387: 3343: 3322: 3314: 3310: 3297: 3282: 3281: 3246: 3242: 3235: 3210: 3201: 3200: 3145: 3124: 3104: 3069: 3068: 3036: 3030: 3023: 3016: 3009: 3005: 2994: 2980: 2949: 2945: 2910: 2903: 2875: 2866: 2857: 2854: 2849: 2847: 2843: 2839: 2828: 2824: 2818: 2816: 2815: 2811: 2800: 2797: 2794: 2793: 2791: 2787: 2733: 2722: 2721: 2717: 2670: 2660: 2654: 2641: 2625: 2620: 2619: 2615: 2611: 2604: 2593: 2545: 2534: 2528: 2515: 2499: 2494: 2493: 2489: 2482: 2480: 2479: 2431: 2416: 2410: 2397: 2381: 2376: 2375: 2371: 2367: 2363: 2355: 2352: 2337:1.151 3 Np 2320: 2318: 2308: 2306: 2295: 2293: 2286: 2284: 2273: 2271: 2264: 2262: 2254: 2252: 2208: 2193: 2186: 2179: 2172: 2131: 2121: 2115: 2114: 2099: 2089: 2082: 2081: 2076: 2069: 2009: 1995: 1989: 1988: 1973: 1959: 1952: 1951: 1937: 1907: 1896: 1855: 1845: 1839: 1828: 1812: 1807: 1806: 1801: 1754: 1740: 1730: 1724: 1713: 1712: 1673: 1664: 1651: 1608: 1602: 1591: 1563: 1554: 1537: 1532: 1531: 1526: 1520:(measured) and 1514: 1508: 1482: 1468: 1458: 1452: 1441: 1440: 1435: 1426: 1412: 1403: 1392: 1383: 1372: 1362: 1352: 1350: 1305: 1296: 1285: 1257: 1248: 1221: 1216: 1215: 1210: 1201: 1175: 1127: 1125: 1120: 1118: 1110: 1108: 1099: 1097: 1091: 1089: 1085: 1074: 1053: 1049: 1048: 1046: 1037: 1033: 1032: 1028: 1010: 1001: 999: 986: 984: 975: 972: 969: 967: 953: 950: 948: 939: 936: 934: 920: 918: 909: 906: 904: 890: 887: 885: 876: 873: 871: 851: 849: 835: 833: 824: 822: 802: 800: 786: 784: 747: 745: 723: 720: 717: 716: 714: 702: 699: 696: 695: 693: 674: 671: 668: 667: 665: 664: 662: 650: 647: 644: 643: 641: 577: 575: 498: 496: 478: 476: 457: 455: 442: 440: 432: 429: 427: 414: 412: 404: 401: 399: 386: 384: 376: 373: 371: 358: 356: 348: 345: 342: 340: 327: 325: 317: 314: 311: 309: 290: 179: 168: 154:of amplifiers, 84: 80: 43: 28: 23: 22: 15: 12: 11: 5: 8316: 8314: 8306: 8305: 8303:Units of level 8300: 8295: 8290: 8285: 8275: 8274: 8268: 8267: 8265: 8264: 8253: 8250: 8249: 8247: 8246: 8241: 8236: 8231: 8226: 8220: 8218: 8214: 8213: 8211: 8210: 8205: 8200: 8195: 8190: 8185: 8180: 8175: 8170: 8165: 8160: 8155: 8150: 8144: 8142: 8136: 8135: 8133: 8132: 8127: 8122: 8117: 8112: 8107: 8102: 8097: 8092: 8087: 8082: 8077: 8072: 8067: 8062: 8057: 8052: 8047: 8042: 8037: 8035:degree Celsius 8032: 8027: 8021: 8019: 8015:Derived units 8011: 8010: 8008: 8007: 8002: 7997: 7992: 7987: 7982: 7977: 7971: 7969: 7963: 7962: 7957: 7955: 7954: 7947: 7940: 7932: 7923: 7922: 7920: 7919: 7914: 7909: 7904: 7899: 7895: 7892: 7891: 7889: 7888: 7883: 7878: 7873: 7868: 7863: 7858: 7852: 7847: 7846: 7845: 7835: 7830: 7825: 7818: 7815: 7814: 7805: 7803: 7802: 7795: 7788: 7780: 7774: 7773: 7767: 7762: 7757: 7750: 7749:External links 7747: 7746: 7745: 7711: 7696: 7693: 7690: 7689: 7686:. 16 May 2013. 7671: 7653: 7613: 7589: 7573:Mark E. Long. 7565: 7541: 7517: 7501: 7488: 7464: 7454: 7428: 7422:978-0750648448 7421: 7403: 7377: 7351: 7325: 7314: 7305: 7299:978-0750671750 7298: 7272: 7254: 7244: 7229: 7215: 7206: 7199: 7179: 7172: 7155: 7138:"DB or Not DB" 7128: 7104: 7085: 7078: 7058: 7051: 7029: 7022: 7002: 6995: 6975: 6968: 6948: 6941: 6923: 6889: 6863: 6854: 6845: 6836: 6819: 6802: 6785: 6768: 6751: 6734: 6728:R. J. Peters, 6721: 6707: 6682: 6673: 6661: 6652: 6643: 6601: 6592: 6585: 6564: 6543: 6528: 6505: 6488: 6464: 6445:(6): 550–555. 6429: 6410: 6392: 6371: 6345: 6338: 6332:. p. 35. 6314: 6295: 6288: 6271: 6253: 6237: 6221: 6211: 6182: 6152: 6151: 6149: 6146: 6143: 6142: 6133: 6123: 6122: 6120: 6117: 6116: 6115: 6110: 6105: 6100: 6095: 6090: 6085: 6080: 6075: 6073:dB drag racing 6070: 6062: 6056: 6051: 6044: 6041: 6040: 6039: 6028: 6024: 6023: 6021:antenna factor 6017: 6014: 6004: 6001: 5998: 5993: 5992:Other suffixes 5990: 5989: 5988: 5980: 5968: 5941: 5938: 5937: 5936: 5929: 5926: 5919: 5916: 5909: 5906: 5903: 5900: 5893: 5888: 5885: 5884: 5883: 5874:relative to 1 5868: 5865: 5855: 5852: 5849: 5846: 5843: 5840: 5835: 5829: 5826: 5819: 5816: 5815:dB volume unit 5813: 5810: 5800: 5797: 5794: 5791: 5788: 5785: 5782: 5779: 5776: 5773: 5770: 5751: 5748: 5745: 5735: 5732: 5720: 5700: 5697: 5694:peak amplitude 5690: 5687: 5684: 5681: 5671: 5668: 5658: 5653: 5650: 5647: 5644: 5641: 5638: 5635: 5632: 5629: 5618: 5615: 5612: 5609: 5606: 5603: 5593: 5590: 5587: 5584: 5581: 5578: 5573: 5566: 5561: 5547: 5544: 5537: 5534: 5523: 5520: 5513: 5510: 5495: 5492: 5486: 5483: 5460: 5455: 5448: 5445: 5444:dB electrical. 5442: 5439: 5436:dipole antenna 5428: 5425: 5418: 5415: 5408: 5405: 5398: 5393: 5386: 5383: 5376: 5373: 5366: 5361: 5358: 5356: 5353: 5352: 5351: 5315: 5312: 5298: 5295: 5284: 5281: 5271: 5266: 5263: 5260: 5240: 5237: 5234: 5231: 5205: 5178: 5157: 5154: 5149: 5145: 5124: 5121: 5113: 5106: 5099: 5095: 5091: 5086: 5082: 5077: 5073: 5069: 5066: 5057: 5037: 5032: 5017: 5012: 5009: 5008: 5007: 5004:antenna factor 5000: 4997: 4990: 4987: 4984: 4981: 4974: 4971: 4968:dipole antenna 4960: 4957: 4942: 4937: 4934: 4933: 4932: 4929: 4926: 4925:dB electrical. 4923: 4920: 4913: 4910: 4903: 4900: 4893: 4890: 4864: 4861: 4854: 4849: 4838: 4835: 4832: 4829: 4822: 4815: 4812: 4811: 4810: 4803: 4800: 4799:precipitation. 4796: 4789: 4786: 4785: 4784: 4780:peak amplitude 4776: 4773: 4772:dB volume unit 4770: 4767: 4744: 4739: 4732: 4727: 4720: 4710: 4707: 4706: 4705: 4702: 4699: 4696: 4693: 4687: 4684: 4669: 4666: 4658: 4651:IEC 61672-2013 4642: 4630: 4627: 4620: 4617: 4606: 4603: 4600:sound in water 4584: 4571: 4568: 4567: 4566: 4556: 4553: 4549: 4548: 4533: 4530: 4526: 4525: 4493: 4473: 4450: 4447: 4444: 4439: 4436: 4395: 4386: 4383: 4379: 4373: 4367: 4354: 4349: 4343: 4339: 4334: 4330: 4326: 4323: 4292: 4289: 4278: 4275: 4272: 4268: 4263: 4260: 4242: 4238: 4237: 4215: 4212: 4192:voltage source 4176: 4173: 4171: 4168: 4139: 4127: 4119: 4106: 4098: 4088: 4079: 4058: 4055: 4022: 4019: 3987: 3984: 3975: 3974:≈ 0.775 V 3905: 3902: 3885: 3882: 3848: 3847: 3836: 3826: 3815: 3811: 3806: 3799: 3795: 3791: 3788: 3783: 3779: 3750: 3739: 3733: 3732: 3721: 3711: 3700: 3690: 3684: 3677: 3673: 3669: 3666: 3661: 3657: 3625: 3622: 3613: 3610: 3608: 3605: 3578: 3575: 3562: 3559: 3554: 3550: 3546: 3531: 3530: 3509: 3506: 3496: 3492: 3489: 3484: 3480: 3476: 3471: 3464: 3460: 3456: 3452: 3448: 3443: 3439: 3435: 3431: 3425: 3420: 3415: 3411: 3406: 3402: 3399: 3396: 3393: 3391: 3389: 3379: 3375: 3371: 3365: 3358: 3354: 3350: 3346: 3342: 3337: 3333: 3329: 3325: 3319: 3313: 3309: 3304: 3300: 3296: 3293: 3290: 3287: 3285: 3283: 3280: 3276: 3271: 3261: 3258: 3249: 3245: 3241: 3238: 3236: 3234: 3231: 3228: 3225: 3222: 3213: 3209: 3208: 3198: 3181: 3178: 3167: 3160: 3156: 3152: 3148: 3144: 3139: 3135: 3131: 3127: 3121: 3116: 3111: 3107: 3103: 3100: 3097: 3088: 3085: 3076: 3052:= 87 dB; 3045:sound pressure 3029: 3026: 3021: 3014: 3007: 3003: 2992: 2978: 2953: 2952: 2947: 2943: 2902: 2899: 2874: 2871: 2865: 2862: 2784: 2783: 2772: 2769: 2766: 2763: 2759: 2756: 2753: 2750: 2744: 2741: 2736: 2732: 2729: 2714: 2697: 2694: 2684: 2673: 2663: 2657: 2653: 2648: 2644: 2640: 2637: 2632: 2628: 2600: 2591: 2590: 2573: 2570: 2560: 2548: 2537: 2531: 2527: 2522: 2518: 2514: 2511: 2506: 2502: 2476: 2459: 2456: 2446: 2434: 2423: 2419: 2413: 2409: 2404: 2400: 2396: 2393: 2388: 2384: 2351: 2348: 2345: 2344: 2341: 2338: 2335: 2332: 2329: 2325: 2324: 2312: 2303: 2300: 2291: 2282: 2278: 2277: 2268: 2259: 2250: 2247: 2244: 2240: 2239: 2236: 2233: 2227: 2224: 2221: 2207: 2204: 2191: 2184: 2177: 2170: 2164: 2163: 2150: 2145: 2138: 2134: 2128: 2124: 2118: 2113: 2106: 2102: 2096: 2092: 2074: 2067: 2042: 2041: 2028: 2023: 2016: 2012: 2007: 2004: 2001: 1998: 1992: 1987: 1980: 1976: 1971: 1968: 1965: 1962: 1936: 1933: 1925:field quantity 1921:field quantity 1905: 1894: 1888: 1887: 1869: 1858: 1848: 1842: 1835: 1831: 1827: 1824: 1819: 1815: 1797: 1777:Similarly, in 1775: 1774: 1761: 1757: 1743: 1737: 1733: 1727: 1723: 1720: 1706: 1705: 1687: 1680: 1676: 1672: 1667: 1663: 1658: 1654: 1650: 1647: 1637: 1630: 1625: 1621: 1615: 1611: 1605: 1598: 1594: 1590: 1587: 1577: 1570: 1566: 1562: 1557: 1552: 1549: 1544: 1540: 1524: 1510:Main article: 1507: 1504: 1503: 1502: 1489: 1485: 1471: 1465: 1461: 1455: 1451: 1448: 1431: 1424: 1408: 1401: 1388: 1381: 1368: 1360: 1348: 1338: 1337: 1319: 1312: 1308: 1304: 1299: 1292: 1288: 1284: 1281: 1271: 1264: 1260: 1256: 1251: 1246: 1241: 1238: 1233: 1228: 1224: 1206: 1199: 1174: 1171: 1157:power quantity 1016: 1015: 1008: 991: 990: 982: 979: 965: 962: 958: 957: 946: 943: 932: 929: 925: 924: 916: 913: 902: 899: 895: 894: 883: 880: 869: 866: 862: 861: 858: 855: 847: 844: 840: 839: 831: 828: 820: 817: 813: 812: 809: 806: 798: 795: 791: 790: 782: 779: 776: 773: 769: 768: 765: 762: 759: 756: 752: 751: 743: 740: 737: 734: 730: 729: 711: 708: 690: 687: 683: 682: 659: 656: 638: 635: 631: 630: 627: 624: 621: 618: 614: 613: 611: 608: 606: 603: 599: 598: 595: 592: 589: 586: 582: 581: 572: 569: 566: 563: 559: 558: 555: 552: 549: 546: 542: 541: 538: 535: 533: 530: 526: 525: 523: 520: 518: 515: 511: 510: 507: 504: 502: 494: 490: 489: 487: 484: 482: 474: 470: 469: 466: 463: 461: 453: 449: 448: 446: 438: 436: 425: 421: 420: 418: 410: 408: 397: 393: 392: 390: 382: 380: 369: 365: 364: 362: 354: 352: 338: 334: 333: 331: 323: 321: 307: 303: 302: 299: 296: 289: 286: 194:of 0.054  167: 164: 148:control theory 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 8315: 8304: 8301: 8299: 8296: 8294: 8291: 8289: 8286: 8284: 8281: 8280: 8278: 8263: 8255: 8254: 8251: 8245: 8242: 8240: 8237: 8235: 8232: 8230: 8227: 8225: 8222: 8221: 8219: 8215: 8209: 8206: 8204: 8201: 8199: 8196: 8194: 8191: 8189: 8186: 8184: 8181: 8179: 8176: 8174: 8171: 8169: 8168:degree of arc 8166: 8164: 8161: 8159: 8156: 8154: 8151: 8149: 8146: 8145: 8143: 8141: 8137: 8131: 8128: 8126: 8123: 8121: 8118: 8116: 8113: 8111: 8108: 8106: 8103: 8101: 8098: 8096: 8093: 8091: 8088: 8086: 8083: 8081: 8078: 8076: 8073: 8071: 8068: 8066: 8063: 8061: 8058: 8056: 8053: 8051: 8048: 8046: 8043: 8041: 8038: 8036: 8033: 8031: 8028: 8026: 8023: 8022: 8020: 8018: 8012: 8006: 8003: 8001: 7998: 7996: 7993: 7991: 7988: 7986: 7983: 7981: 7978: 7976: 7973: 7972: 7970: 7968: 7964: 7960: 7953: 7948: 7946: 7941: 7939: 7934: 7933: 7930: 7918: 7915: 7913: 7910: 7908: 7905: 7903: 7900: 7897: 7896: 7893: 7887: 7884: 7882: 7879: 7877: 7874: 7872: 7869: 7867: 7864: 7862: 7859: 7856: 7853: 7851: 7848: 7844: 7841: 7840: 7839: 7836: 7834: 7831: 7829: 7826: 7823: 7820: 7819: 7816: 7811: 7808: 7801: 7796: 7794: 7789: 7787: 7782: 7781: 7778: 7771: 7768: 7766: 7763: 7761: 7758: 7756: 7753: 7752: 7748: 7731: 7728:(in German). 7723: 7719: 7718: 7712: 7708: 7705:(in German). 7704: 7699: 7698: 7694: 7685: 7684:wordpress.com 7681: 7675: 7672: 7667: 7663: 7657: 7654: 7649: 7643: 7627: 7623: 7617: 7614: 7602: 7601: 7593: 7590: 7578: 7577: 7569: 7566: 7554: 7553: 7545: 7542: 7530: 7529: 7521: 7518: 7515: 7514:0-932764-04-5 7511: 7505: 7502: 7498: 7492: 7489: 7477: 7476: 7472:David Adamy. 7468: 7465: 7458: 7455: 7442: 7438: 7432: 7429: 7424: 7418: 7414: 7407: 7404: 7391: 7387: 7381: 7378: 7365: 7361: 7355: 7352: 7339: 7335: 7329: 7326: 7323: 7322:ITU-R BS.1770 7318: 7315: 7309: 7306: 7301: 7295: 7291: 7286: 7285: 7276: 7273: 7268: 7264: 7258: 7255: 7248: 7245: 7241: 7238: 7233: 7230: 7225: 7219: 7216: 7210: 7207: 7202: 7196: 7192: 7191: 7183: 7180: 7175: 7169: 7165: 7159: 7156: 7143: 7139: 7132: 7129: 7124: 7120: 7119: 7114: 7108: 7105: 7100: 7096: 7093:Stas Bekman. 7089: 7086: 7081: 7075: 7071: 7070: 7062: 7059: 7054: 7048: 7044: 7040: 7033: 7030: 7025: 7019: 7015: 7014: 7006: 7003: 6998: 6992: 6988: 6987: 6979: 6976: 6971: 6965: 6961: 6960: 6952: 6949: 6944: 6942:0-87942-274-2 6938: 6934: 6927: 6924: 6909: 6902: 6901: 6893: 6890: 6877: 6873: 6867: 6864: 6858: 6855: 6849: 6846: 6843:ISO 1683:2015 6840: 6837: 6834: 6831:, p. 304, at 6830: 6829: 6823: 6820: 6817: 6813: 6812: 6806: 6803: 6800: 6797:, p. 407, at 6796: 6795: 6789: 6786: 6783: 6780:, p. 356, at 6779: 6778: 6772: 6769: 6766: 6762: 6761: 6755: 6752: 6749: 6746:, p. 268, at 6745: 6744: 6738: 6735: 6731: 6725: 6722: 6717: 6711: 6708: 6704: 6700: 6696: 6692: 6686: 6683: 6677: 6674: 6671: 6665: 6662: 6656: 6653: 6647: 6644: 6640: 6636: 6632: 6628: 6624: 6620: 6616: 6612: 6605: 6602: 6596: 6593: 6588: 6582: 6578: 6574: 6568: 6565: 6561: 6557: 6553: 6547: 6544: 6539: 6532: 6529: 6526: 6522: 6516: 6514: 6512: 6510: 6506: 6501: 6495: 6493: 6489: 6481: 6474: 6468: 6465: 6460: 6456: 6452: 6448: 6444: 6440: 6433: 6430: 6425: 6421: 6414: 6411: 6407: 6404:, p. 276, at 6403: 6402: 6396: 6393: 6388: 6384: 6383: 6375: 6372: 6367: 6363: 6359: 6355: 6349: 6346: 6341: 6335: 6331: 6327: 6326: 6318: 6315: 6310: 6306: 6299: 6296: 6291: 6285: 6281: 6275: 6272: 6269: 6265: 6262: 6257: 6254: 6242: 6241: 6230: 6228: 6226: 6222: 6218: 6214: 6208: 6204: 6199: 6198: 6189: 6187: 6183: 6179: 6175: 6171: 6167: 6160: 6158: 6154: 6147: 6137: 6134: 6128: 6125: 6118: 6114: 6111: 6109: 6106: 6104: 6101: 6099: 6096: 6094: 6091: 6089: 6086: 6084: 6081: 6079: 6076: 6074: 6071: 6068: 6060: 6057: 6055: 6052: 6050: 6047: 6046: 6042: 6037: 6033: 6029: 6026: 6025: 6022: 6018: 6015: 6013: 6009: 6005: 6002: 5999: 5996: 5995: 5991: 5986: 5977: 5973: 5969: 5967: 5963: 5959: 5955: 5951: 5947: 5944: 5943: 5939: 5934: 5930: 5927: 5924: 5920: 5917: 5914: 5910: 5907: 5904: 5901: 5898: 5894: 5891: 5890: 5886: 5881: 5877: 5873: 5869: 5866: 5863: 5858: 5853: 5850: 5847: 5844: 5841: 5839: 5836: 5833: 5830: 5827: 5824: 5820: 5817: 5814: 5811: 5808: 5803: 5798: 5795: 5792: 5789: 5786: 5783: 5780: 5777: 5774: 5771: 5749: 5746: 5743: 5733: 5730: 5718: 5707: 5704: 5701: 5698: 5695: 5691: 5688: 5685: 5682: 5679: 5675: 5672: 5669: 5667: 5663: 5659: 5657: 5654: 5651: 5648: 5645: 5642: 5639: 5636: 5633: 5630: 5627: 5623: 5619: 5616: 5613: 5610: 5607: 5604: 5601: 5596: 5591: 5588: 5585: 5582: 5579: 5577: 5574: 5571: 5567: 5565: 5562: 5559: 5555: 5551: 5548: 5545: 5542: 5538: 5535: 5532: 5528: 5524: 5521: 5518: 5514: 5511: 5508: 5504: 5500: 5496: 5493: 5490: 5487: 5484: 5481: 5477: 5473: 5469: 5465: 5461: 5459: 5456: 5453: 5449: 5446: 5443: 5440: 5437: 5433: 5429: 5426: 5423: 5419: 5416: 5413: 5409: 5406: 5403: 5399: 5397: 5394: 5391: 5387: 5384: 5381: 5380:dBrn adjusted 5377: 5374: 5371: 5367: 5364: 5363: 5359: 5354: 5349: 5345: 5341: 5338: 5334: 5330: 5326: 5325: 5320: 5316: 5313: 5310: 5306: 5302: 5299: 5296: 5293: 5288: 5285: 5282: 5280: 5276: 5272: 5270: 5267: 5264: 5261: 5238: 5235: 5232: 5229: 5222:is therefore 5203: 5176: 5155: 5152: 5147: 5143: 5122: 5104: 5097: 5093: 5089: 5084: 5080: 5075: 5071: 5067: 5064: 5055: 5046: 5042: 5038: 5036: 5033: 5030: 5026: 5022: 5018: 5015: 5014: 5010: 5005: 5001: 4998: 4995: 4991: 4988: 4985: 4982: 4979: 4975: 4972: 4969: 4965: 4961: 4958: 4955: 4951: 4947: 4943: 4940: 4939: 4935: 4930: 4927: 4924: 4921: 4918: 4914: 4911: 4908: 4904: 4901: 4898: 4894: 4891: 4888: 4884: 4881: 4877: 4873: 4869: 4865: 4862: 4859: 4855: 4853: 4850: 4847: 4843: 4839: 4836: 4833: 4830: 4827: 4823: 4821: 4818: 4817: 4813: 4808: 4804: 4801: 4797: 4795: 4792: 4791: 4787: 4781: 4777: 4774: 4771: 4768: 4765: 4761: 4757: 4753: 4749: 4745: 4743: 4740: 4737: 4733: 4731: 4728: 4725: 4721: 4719: 4716: 4715: 4714: 4708: 4703: 4700: 4697: 4694: 4692: 4688: 4685: 4682: 4678: 4674: 4673:hearing level 4670: 4667: 4664: 4656: 4652: 4648: 4639: 4635: 4631: 4628: 4625: 4621: 4618: 4615: 4611: 4607: 4604: 4601: 4589: 4586:dB SPL ( 4585: 4582: 4581: 4580: 4577: 4569: 4564: 4559: 4554: 4551: 4550: 4545: 4541: 4536: 4531: 4528: 4527: 4507: 4491: 4471: 4448: 4445: 4442: 4437: 4434: 4425: 4421: 4417: 4413: 4409: 4393: 4384: 4381: 4377: 4371: 4365: 4352: 4347: 4341: 4337: 4332: 4328: 4324: 4321: 4313: 4290: 4287: 4276: 4273: 4266: 4261: 4258: 4249: 4246: 4243: 4240: 4239: 4227: 4223: 4218: 4213: 4210: 4209: 4205: 4201: 4197: 4193: 4189: 4184: 4180: 4174: 4169: 4167: 4165: 4161: 4155: 4152: 4149: 4142: 4138: 4130: 4126: 4118: 4114: 4105: 4101: 4097: 4087: 4082: 4078: 4073: 4067: 4063: 4056: 4054: 4052: 4047: 4043: 4040: 4039:dynamic range 4036: 4032: 4028: 4027:image sensors 4020: 4018: 4016: 4012: 4011:blocking unit 4007: 4005: 4001: 3997: 3993: 3985: 3983: 3981: 3966: 3962: 3957: 3955: 3949: 3947: 3943: 3939: 3938:coaxial cable 3935: 3931: 3927: 3923: 3919: 3915: 3911: 3903: 3901: 3899: 3895: 3891: 3883: 3880: 3875: 3873: 3869: 3864: 3862: 3858: 3853: 3852:dynamic range 3834: 3824: 3813: 3809: 3804: 3797: 3793: 3789: 3786: 3781: 3777: 3769: 3768: 3767: 3765: 3761: 3758: 3756: 3749: 3745: 3738: 3719: 3709: 3698: 3688: 3682: 3675: 3671: 3667: 3664: 3659: 3655: 3647: 3646: 3645: 3643: 3639: 3635: 3632:as a unit of 3631: 3623: 3621: 3619: 3611: 3606: 3604: 3602: 3598: 3594: 3591: 3587: 3586:optical fiber 3583: 3576: 3574: 3560: 3557: 3552: 3548: 3544: 3536: 3507: 3504: 3494: 3490: 3487: 3482: 3478: 3474: 3462: 3458: 3454: 3450: 3446: 3441: 3437: 3433: 3429: 3418: 3413: 3409: 3404: 3400: 3397: 3394: 3392: 3377: 3373: 3369: 3356: 3352: 3348: 3344: 3340: 3335: 3331: 3327: 3323: 3311: 3307: 3302: 3298: 3294: 3291: 3288: 3286: 3278: 3274: 3269: 3259: 3256: 3247: 3243: 3239: 3237: 3229: 3226: 3223: 3211: 3199: 3179: 3176: 3158: 3154: 3150: 3146: 3142: 3137: 3133: 3129: 3125: 3114: 3109: 3105: 3101: 3098: 3095: 3086: 3083: 3074: 3067: 3066: 3065: 3063: 3057: 3056:= 80 dB. 3055: 3051: 3046: 3040: 3035: 3027: 3025: 3020: 3013: 3002: 2998: 2991: 2988: 2984: 2977: 2973: 2970: 2966: 2962: 2958: 2940: 2939: 2938: 2936: 2932: 2928: 2922: 2918: 2914: 2908: 2900: 2898: 2896: 2895: 2894:Semi-log plot 2890: 2889: 2884: 2880: 2872: 2870: 2863: 2861: 2837: 2832: 2809: 2770: 2767: 2764: 2761: 2757: 2754: 2751: 2748: 2742: 2739: 2734: 2730: 2727: 2715: 2695: 2692: 2682: 2671: 2661: 2655: 2651: 2646: 2642: 2638: 2635: 2630: 2626: 2609: 2608: 2607: 2603: 2599: 2571: 2568: 2558: 2546: 2535: 2529: 2525: 2520: 2516: 2512: 2509: 2504: 2500: 2477: 2457: 2454: 2444: 2432: 2421: 2417: 2411: 2407: 2402: 2398: 2394: 2391: 2386: 2382: 2361: 2360: 2359: 2349: 2342: 2339: 2336: 2333: 2330: 2327: 2326: 2316: 2313: 2304: 2301: 2292: 2283: 2280: 2279: 2269: 2260: 2251: 2248: 2245: 2242: 2241: 2237: 2234: 2232: 2228: 2225: 2222: 2219: 2218: 2212: 2205: 2203: 2201: 2197: 2190: 2183: 2176: 2169: 2148: 2143: 2136: 2132: 2126: 2122: 2116: 2111: 2104: 2100: 2094: 2090: 2080: 2079: 2078: 2073: 2066: 2061: 2059: 2055: 2051: 2047: 2046:linear system 2026: 2021: 2014: 2010: 2002: 1996: 1990: 1985: 1978: 1974: 1966: 1960: 1950: 1949: 1948: 1946: 1942: 1934: 1932: 1930: 1926: 1922: 1918: 1914: 1909: 1904: 1900: 1893: 1867: 1856: 1846: 1840: 1833: 1829: 1825: 1822: 1817: 1813: 1805: 1804: 1803: 1800: 1796: 1792: 1788: 1784: 1780: 1759: 1755: 1741: 1735: 1731: 1725: 1721: 1718: 1711: 1710: 1709: 1685: 1678: 1674: 1670: 1665: 1661: 1656: 1652: 1648: 1645: 1635: 1628: 1623: 1619: 1613: 1609: 1603: 1596: 1592: 1588: 1585: 1575: 1568: 1564: 1560: 1555: 1550: 1547: 1542: 1538: 1530: 1529: 1528: 1523: 1519: 1513: 1505: 1487: 1483: 1469: 1463: 1459: 1453: 1449: 1446: 1439: 1438: 1437: 1434: 1430: 1423: 1419: 1414: 1413:is negative. 1411: 1407: 1400: 1397:is less than 1396: 1391: 1387: 1380: 1376: 1371: 1367: 1359: 1355: 1347: 1343: 1317: 1310: 1306: 1302: 1297: 1290: 1286: 1282: 1279: 1269: 1262: 1258: 1254: 1249: 1244: 1239: 1236: 1231: 1226: 1222: 1214: 1213: 1212: 1209: 1205: 1198: 1194: 1190: 1186: 1182: 1181: 1172: 1170: 1169:for details. 1168: 1167: 1162: 1158: 1153: 1151: 1147: 1143: 1142: 1137: 1132: 1115: 1105: 1083: 1082: 1072: 1071: 1066: 1062: 1044: 1041: ln(10) 1026: 1021: 1014: 1004: 997: 992: 983: 980: 966: 963: 960: 959: 947: 944: 933: 930: 927: 926: 917: 914: 903: 900: 897: 896: 884: 881: 870: 867: 864: 863: 859: 856: 848: 845: 842: 841: 832: 829: 821: 818: 815: 814: 810: 807: 799: 796: 793: 792: 783: 780: 777: 774: 771: 770: 766: 763: 760: 757: 754: 753: 744: 741: 738: 735: 732: 731: 712: 709: 691: 688: 685: 684: 660: 657: 639: 636: 633: 632: 628: 625: 622: 619: 616: 615: 612: 609: 607: 604: 601: 600: 596: 593: 590: 587: 584: 583: 573: 570: 567: 564: 561: 560: 556: 553: 550: 547: 544: 543: 539: 536: 534: 531: 528: 527: 524: 521: 519: 516: 513: 512: 508: 505: 503: 495: 492: 491: 488: 485: 483: 475: 472: 471: 467: 464: 462: 454: 451: 450: 447: 439: 437: 426: 423: 422: 419: 411: 409: 398: 395: 394: 391: 383: 381: 370: 367: 366: 363: 355: 353: 339: 336: 335: 332: 324: 322: 308: 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Index

DBrnC
sound
Sound pressure level
Decibel (disambiguation)
unit of measurement
power or root-power quantity
logarithmic scale
levels
volt
V
logarithm with base 10
telephony
Bell System
Alexander Graham Bell
engineering
sound power
acoustics
electronics
control theory
gains
attenuation
signal-to-noise ratios
mile
radians
shunt
capacitance
microfarads
gauge
Bell Telephone Laboratories
Alexander Graham Bell

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