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.
Other articles related to "signal, noise, signals, noise signal":
... panel can be broken up into 3 sections The signal generators (the 3 VCO's or Voltage-controlled oscillator and pink or white noise) The filter (the VCF or voltage-controlled filter) The amplifier (the ... first choose a sound shape to be generated from the VCO(s) and/or the type of Noise (White or Pink) ... wave in oscillator 3) square wave 2 different width pulse waves The signals are routed through the Mixer to the VCF (Voltage Controlled Filter) where ...
... the transmitted message is modelled as an analog signal ... errors), time-invariant or time-variant (also resulting in burst errors), baseband, passband (RF signal model), real-valued or complex-valued signal model ... The model may reflect the following channel impairments Noise model, for example Additive white Gaussian noise (AWGN) channel, a linear continuous memoryless model Phase ...
... transmissions multiply the data being transmitted by a "noise" signal ... This noise signal is a pseudorandom sequence of 1 and −1 values, at a frequency much higher than that of the original signal ... The resulting signal resembles white noise, like an audio recording of "static" ...
Famous quotes related to noise:
“I hate the noise and hurry inseparable from great Estates and Titles, and look upon both as blessings that ought only to be given to fools, for tis only to them that they are blessings.”
—Mary Wortley, Lady Montagu (16891762)
“Sweet bird, that shunnst the noise of folly,
Most musical, most melancholy!”
—John Milton (16081674)
“With the noise of the mourning of the Swattish nation!
Fallen is at length
Its tower of strength;
Its sun is dimmed ere it had nooned;
Dead lies the great Ahkoond,
The great Ahkoond of Swat
—George Thomas Lanigan (18451886)
“At length I heard a ragged noise and mirth
Of thieves and murderers: there I him espied
Who straight, Your suit is granted,said, and died.”
—George Herbert (15931633)
“The filth and noise of the crowded streets soon destroy the elasticity of health which belongs to the country boy.”
—Rutherford Birchard Hayes (18221893)