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  2. Noise curve - Wikipedia

    en.wikipedia.org/wiki/Noise_curve

    Noise curves are a common way to characterise background noise in unoccupied buildings and spaces. [1] Their purpose is to produce a single-value representation of a complete sound spectrum. International standards organizations ( ISO , [ 2 ] ANSI [ 3 ] and ASA ) recognize the need to objectify judgements on the amount of ambient noise in ...

  3. Dynamic range - Wikipedia

    en.wikipedia.org/wiki/Dynamic_range

    Multiple noise processes determine the noise floor of a system. Noise can be picked up from microphone self-noise, preamp noise, wiring and interconnection noise, media noise, etc. Early 78 rpm phonograph discs had a dynamic range of up to 40 dB, [24] soon reduced to 30 dB and worse due to wear from repeated play. Vinyl microgroove phonograph ...

  4. Decibel - Wikipedia

    en.wikipedia.org/wiki/Decibel

    The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was miles of standard cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a ...

  5. Sound exposure - Wikipedia

    en.wikipedia.org/wiki/Sound_exposure

    Sound exposure level (SEL) is a logarithmic measure of the sound exposure of a sound relative to a reference value. Sound exposure level, denoted L E and measured in dB , is defined by [ 1 ]

  6. Noise figure - Wikipedia

    en.wikipedia.org/wiki/Noise_figure

    The noise figure is the difference in decibel (dB) between the noise output of the actual receiver to the noise output of an "ideal" receiver with the same overall gain and bandwidth when the receivers are connected to matched sources at the standard noise temperature T 0 (usually 290 K).

  7. Ambient noise level - Wikipedia

    en.wikipedia.org/wiki/Ambient_noise_level

    Ambient noise level is measured with a sound level meter. [4] It is usually measured in dB relative to a reference pressure of 0.00002 Pa, i.e., 20 μPa (micropascals) in SI units. [5] This is because 20 μPa is the faintest sound the human ear can detect. [5] A pascal is a newton per square meter. The centimeter-gram-second system of units ...

  8. Signal-to-noise ratio - Wikipedia

    en.wikipedia.org/wiki/Signal-to-noise_ratio

    Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise.

  9. Noise level - Wikipedia

    en.wikipedia.org/wiki/Noise_level

    The noise level is the level of noise. Specifically, it may refer to: Noise (electronics) Ambient noise level; Environmental noise This page was last edited on 24 ...