| 释义 |
decibel
 decibelrange of human hearing in decibelsde·ci·bel D0071800 (dĕs′ə-bəl, -bĕl′)n. Abbr. dB A unit used to express relative difference in power or intensity, usually between two acoustic or electric signals, equal to ten times the common logarithm of the ratio of the two levels.
[deci- + bel.]decibel (ˈdɛsɪˌbɛl) n1. (Units) a unit for comparing two currents, voltages, or power levels, equal to one tenth of a bel2. (Units) a similar unit for measuring the intensity of a sound. It is equal to ten times the logarithm to the base ten of the ratio of the intensity of the sound to be measured to the intensity of some reference sound, usually the lowest audible note of the same frequencyAbbreviation: dB dec•i•bel (ˈdɛs əˌbɛl, -bəl)
n. a unit used to express differences in power, esp. in acoustics or electronics: equal to ten times the common logarithm of the ratio of two signals. Abbr.: dB [1925–30; deci- + bel] de·ci·bel (dĕs′ə-bəl) A unit used to measure the loudness or intensity of a sound. The speaking voice of most people ranges from 45 to 75 decibels. See Note at sound1.decibel1. A logarithmic unit of sound intensity.2. (dB) A measure of relative sound intensity.Thesaurus| Noun | 1. | decibel - a logarithmic unit of sound intensity; 10 times the logarithm of the ratio of the sound intensity to some reference intensitydBsound unit - any acoustic unit of measurement |
Translationsdecibel (ˈdesibel) , (ˈdesibəl) noun (abbreviation db) the main unit of measurement of the loudness of a sound. Traffic noise is measured in decibels. 分貝 分贝decibel
decibel (dĕs`əbĕl', –bəl), abbr. dB, unit used to measure the loudness of soundsound,
any disturbance that travels through an elastic medium such as air, ground, or water to be heard by the human ear. When a body vibrates, or moves back and forth (see vibration), the oscillation causes a periodic disturbance of the surrounding air or other medium that
..... Click the link for more information. . It is one tenth of a bel (named for A. G. Bell), but the larger unit is rarely used. The decibel is a measure of sound intensity as a function of power ratio, with the difference in decibels between two sounds being given by dB=10 log10(P1/P2), where P1 and P2 are the power levels of the two sounds. The faintest audible sound, corresponding to a sound pressure of about 0.0002 dyne per sq cm, is arbitrarily assigned a value of 0 dB. The loudest sounds that can be tolerated by the human ear are about 120 dB. The level of normal conversation is about 50 to 60 dB. The decibel is also used to measure certain other quantities, such as power loss in telephone lines.Decibel A logarithmic unit used to express the magnitude of a change in level of power, voltage, current, or sound intensity. A decibel (dB) is 1/10 bel. In acoustics a step of 1 bel is too large for most uses. It is therefore the practice to express sound intensity in decibels. The level of a sound of intensity I in decibels relative to a reference intensity IR is given by notation (1). (1)  Because sound intensity is proportional to the square of sound pressure P, the level in decibels is given by Eq. (2). (2)  The reference pressure is usually taken as 0.0002 dyne/cm2 or 0.0002 microbar. (The pressure of the Earth's atmosphere at sea level is approximately 1 bar.) See Sound pressure The neper is similar to the decibel but is based upon natural (napierian) logarithms. One neper is equal to 8.686 dB. Decibel a fractional unit of the bel (a unit of relative logarithmic value—the common logarithm of the ratio of two synonymous physical quantities, such as energy, power, or sound pressure). The decibel is equal to 0.1 bel. Symbols: Russian, db; international, dB. In practice the decibel is more often used than the bel, the basic unit. decibel[′des·ə‚bel] (physics) A unit for describing the ratio of two powers or intensities, or the ratio of a power to a reference power; in the measurement of sound intensity, the pressure of the reference sound is usually taken as 2 × 10-4 dyne per square centimeter; equal to one-tenth bel; if P1 and P2 are two amounts of power, the first is said to be n decibels greater, where n = 10 log10(P1/ P2). Abbreviated dB. decibelThe unit in which the level, 4 of various acoustical quantities is expressed.decibel1. a unit for comparing two currents, voltages, or power levels, equal to one tenth of a bel 2. a similar unit for measuring the intensity of a sound. It is equal to ten times the logarithm to the base ten of the ratio of the intensity of the sound to be measured to the intensity of some reference sound, usually the lowest audible note of the same frequency deciBelA unit of measurement of the loudness or strength of a signal. One deciBel is considered the smallest difference in sound level that the human ear can discern. Created in the early days of telephony as a way to measure cable and equipment performance and named after Alexander Graham Bell, deciBels (dBs) are a relative measurement derived from two signal levels: a reference input level and an observed output level. A deciBel is the logarithm of the ratio of the two levels. One Bel is when the output signal is 10x that of the input, and one deciBel is 1/10th of a Bel.
A whisper is about 20 dB. A normal conversation is typically from 60 to 70 dB, and a noisy factory from 90 to 100 dB. Loud thunder is approximately 110 dB, and 120 dB borders on the threshold of pain. See dBm.
INCREASE IN POWER LEVELS (WATTS)Formula is dB=10*log(P1/P2)DeciBels Output Signal Strength 3dB 2x 6dB 4x 10dB (1 Bel) 10x 20dB 100x 30dB 1,000x 40db 10,000x ATTENUATION OF AMPLITUDE (VOLTS or AMPS)Formula is dB=20*log(A1/A2)DeciBels Output Signal Strength -3dB 0.707x -6dB 0.5x -10dB 0.316x -20dB 0.1x -30dB 0.032x -40db 0.010x
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| Quite a lot was named after Alexander Graham Bell. Throughout the 20th century, the Bell name was ubiquitous. It will live on with the deciBel. |
decibel
decibel [des´ĭ-bel] a unit of relative power intensity equal to one tenth of a bel, used for electric or acoustic power measurements; one decibel equals approximately the smallest difference in acoustic power the human ear can detect and an increase of 10 decibels approximately doubles the loudness of a sound. Abbreviated dB or db. Examples of decibel levels in everyday situations. From Frazier et al., 1996.dec·i·bel (dB, db), (des'i-bel), Avoid the mispronunciation des'i-b'l.One tenth of a bel; unit for expressing the relative intensity of sound on a logarithmic scale. [L. decimus, tenth, + bel] dec·i·bel (dB) (des'i-bĕl) One tenth of a bel; unit for expressing the relative loudness of sound on a logarithmic scale. [L. decimus, tenth, + bel]decibel A logarithmic unit of comparison between a standard power level and an observed level. The decibel is not a unit of sound intensity but is widely used to compare a noise level with a very low standard reference level near the limit of audibility, and to compare electrical power levels. A tenth of a bel.DecibelA unit of measure for expressing the loudness of a sound. Normal speech is typically spoken in the range of about 20-50 decibels.Mentioned in: Audiometry, Hearing Lossdecibel (dB)1. Unit used for the measurement of the intensity of a sound. 2. Light intensities are often presented on a logarithmic (rather than linear) scale. This is done, in particular, to abbreviate large numbers. Moreover, it has become common, especially in perimetry, to use decibels rather than log units. A decibel scale is a logarithmic scale where 10 decibels are equal to 1 log unit; 20 decibels, to 2 log units, etc. In perimetry, decibels are used to indicate the attenuation of brightness of the stimulus. Thus, a 20 dB stimulus is equal to one-tenth the brightness of a 10 dB stimulus.dec·i·bel (dB) (des'i-bĕl) One tenth of a bel. [L. decimus, tenth, + bel]FinancialSeeBELSee DBF
See DOSBoxdecibel
Synonyms for decibelnoun a logarithmic unit of sound intensitySynonymsRelated Words |