Noise

In common use, the word noise means any unwanted sound.

In physics and analog electronics, noise is a mostly unwanted random addition to a signal; it is called noise as a generalisation of the acoustic noise ("static") heard when listening to a weak radio transmission with significant electrical noise. Signal noise is heard as acoustic noise if the signal is converted into sound (e.g., played through a loudspeaker); it manifests as "snow" on a television or video image. High noise levels can block, distort, change or interfere with the meaning of a message in human, animal and electronic communication.

In signal processing or computing it can be considered random unwanted data without meaning; that is, data that is not being used to transmit a signal, but is simply produced as an unwanted by-product of other activities. "Signal-to-noise ratio" is sometimes used to refer to the ratio of useful to irrelevant information in an exchange.

In biology, many different forms of cellular noise exist, where a measurement displays substantial variance around its mean: for example, transcriptional noise describes the variability in gene activity between cells in a population.

In many cases, the special case of thermal noise arises, which sets a fundamental lower limit to what can be measured or signaled and is related to basic physical processes described by thermodynamics, some of which are expressible by simple formulae.

In some fields, noise means unwanted information or data that is not relevant to the hypothesis or theory being investigated or tested.

Read more about Noise:  Acoustic Noise, Use in Music

Other articles related to "noise":

Noise FM 876
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Non-acoustic Noise - Noisy Genes
... Main article Cellular noise The activity and regulation of our genes are also subject to noise ... Transcriptional noise refers to the variability in gene activity between cells in genetically identical populations (even identical twins are non-identical) ... Noise in gene activity has tremendous consequences on cell behaviour, and must be mitigated or integrated ...
Underwater Acoustics - Measurements - Ambient Noise
... processing used and partly by the level of background noise ... Ambient noise is that part of the received noise that is independent of the source, receiver and platform characteristics ... This it excludes reverberation and towing noise for example ...
Bourbon Street - Issues
... Historically noise violations were the responsibility of the party making the noise. 615 Bourbon Street." The case ruled that the property owner, not the noise-maker is responsible for noise violations ... Besides being difficult to enforce, music aficionados claim that noise ordinances threaten the city's music culture ...

Famous quotes containing the word noise:

    The English may not like music, but they absolutely love the noise it makes.
    Thomas Beecham (1879–1961)

    I wonder about the trees.
    Why do we wish to bear
    Forever the noise of these
    More than another noise
    So close to our dwelling place?
    Robert Frost (1874–1963)

    For twenty-five centuries, Western knowledge has tried to look upon the world. It has failed to understand that the world is not for the beholding. It is for hearing. It is not legible, but audible. Our science has always desired to monitor, measure, abstract, and castrate meaning, forgetting that life is full of noise and that death alone is silent: work noise, noise of man, and noise of beast. Noise bought, sold, or prohibited. Nothing essential happens in the absence of noise.
    Jacques Attali (b. 1943)