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Encyclopedia > Analog signal

An analog or analogue signal is any time continuous signal where some time varying feature of the signal is a representation of some other time varying quantity. It differs from a digital signal in that small fluctuations in the signal are meaningful. Analog is usually thought of in an electrical context, however mechanical, pneumatic, hydraulic, and other systems may also convey analog signals. In mathematics, a continuous function is a function for which, intuitively, small changes in the input result in small changes in the output. ... The term digital signal is used to refer to more than one concept. ... Electric redirects here. ... Classical mechanics (commonly confused with Newtonian mechanics, which is a subfield thereof) is used for describing the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. ... Pneumatics, from the Greek πνευματικός (pneumatikos, coming from the wind) is the use of pressurized air in science and technology. ... Hydraulics is a branch of science and engineering concerned with the use of liquids to perform mechanical tasks. ...


An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. Electrically, the property most commonly used is voltage followed closely by frequency, current, and charge. Schematic drawing of a simple mercury barometer with vertical mercury column and reservoir at base A barometer is an instrument used to measure atmospheric pressure. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... For other uses, see Frequency (disambiguation). ... In electricity, current refers to electric current, which is the flow of electric charge. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ...


Any information may be conveyed by an analog signal, often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure, and is achieved using a transducer. A response is the following: Often a response is the result of a stimulus. ... Sound is a disturbance of mechanical energy that propagates through matter as a wave. ... This article does not cite any references or sources. ... For other uses, see Temperature (disambiguation). ... Look up position in Wiktionary, the free dictionary. ... This article is about pressure in the physical sciences. ... A transducer is a device, usually electrical or electronic, that converts one type of energy to another. ...


For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which causes corresponding fluctuations in a voltage or the current in an electric circuit. The voltage or the current is said to be an "analog" of the sound. This article is about pressure in the physical sciences. ... Sound is a disturbance of mechanical energy that propagates through matter as a wave. ... “Microphones” redirects here. ...


Since an analogue signal has a theoretically infinite resolution, it will always have a higher resolution than any digital system where the resolution is in discrete steps. In practice, as analogue systems become more complex, effects such as non linearity and noise ultimately degrade analogue resolution such that digital systems surpass it. In analogue systems it is difficult to detect when such degradation occurs, but in digital systems, degradation can not only be detected, but corrected as well.


Disadvantage

The primary disadvantage of analog signaling is that any system has noise – i.e., random variation. As the signal is copied and re-copied, or transmitted over long distances, these random variations become dominant. Electrically, these losses can be diminished by shielding, good connections, and several cable types such as coaxial or twisted pair. In science, and especially in physics and telecommunication, noise is fluctuations in and the addition of external factors to the stream of target information (signal) being received at a detector. ... Coaxial Cable For the weapon, see coaxial weapon. ... 25 Pair Color Code Chart 10BASE-T UTP Cable Twisted pair cabling is a common form of wiring in which two conductors are wound around each other for the purposes of cancelling out electromagnetic interference known as crosstalk. ...


The effects of noise make signal loss and distortion impossible to recover, since amplifying the signal to recover attenuated parts of the signal amplifies the noise as well. Even if the resolution of an analog signal is higher than a comparable digital signal, in many cases, the difference is overshadowed by the noise in the signal. In science, and especially in physics and telecommunication, noise is fluctuations in and the addition of external factors to the stream of target information (signal) being received at a detector. ...


  Results from FactBites:
 
Analog (485 words)
Analog is usually thought of in an electrical context, however mechanical, pneumatic, hydraulic and other systems also use analog signals.
In this, some base signal (eg a sinusoidal carrier wave) has one of its properties altered: amplitude modulation involves altering the amplitude of a sinusoidal voltage waveform by the source information, frequency modulation changes the frequency.
Any information may be conveyed by an analog signal, often such a signal is a measured response to changes in physical phenomena, such as sound, light, temperature, position, or pressure and is achieved using a transducer.
analog signal: Definition and Much More from Answers.com (639 words)
Analog is usually thought of in an electrical context, however mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.
For example, in an analog sound recording, the variation in pressure of a sound striking a microphone creates a corresponding variation in the voltage amplitude of a current passing through it.
In this, some base signal (e.g., a sinusoidal carrier wave) has one of its properties modulated: amplitude modulation involves altering the amplitude of a sinusoidal voltage waveform by the source information, frequency modulation changes the frequency.
  More results at FactBites »

 
 

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