Analog signal
hideAn Analog or analogue signal is any continuous signal for which the time varying feature (variable) of the signal is a representation of some other time varying quantity, i.e analogous to another time varying signal. 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.
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.
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.
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.
Any measured analog signal must theoretically have noise and a finite slew rate. Therefore, both analog and digital systems are subject to limitations in resolution and bandwidth. In practice, as analog systems become more complex, effects such as non-linearity and noise ultimately degrade analog resolution to such extent that the performance of digital systems may surpass it. In analog systems, it is difficult to detect when such degradation occurs. However, in digital systems, degradation can not only be detected but corrected as well.
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News tagged with analog signals
700,000 callers phone digital TV hot line
Jun 13, 2009 |
2.7 / 5 (3) |
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(AP) -- Nearly 700,000 calls were received by a federal hot line this week from people confused about the nationwide switch from analog to digital TV broadcasts that occurred Friday.
Digital TV likes clear signal path
Dec 31, 2008 |
1.3 / 5 (3) |
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Question: If I buy a new digital TV, can I just plug it in and use it, as I do the old TV now? My son insists that it has to be hooked to an antenna, but the old televisions worked fine without one.
Search results for analog signals
'Self-seeding' of cancer cells may play a critical role in tumor progression
Dec 24, 2009 |
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Cancer progression is commonly thought of as a process involving the growth of a primary tumor followed by metastasis, in which cancer cells leave the primary tumor and spread to distant organs. A new study by researchers ...
What connects the elderly and sports people? Smart sensor technology
Dec 24, 2009 |
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Innovative smart sensing devices promise to boost mobility and quality of life for the elderly, reduce healthcare costs and even give sports people an edge through more effective training.
A novel gene found for childhood-onset asthma
Dec 23, 2009 |
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Pediatric researchers have identified a novel gene involved in childhood asthma, in one of the largest gene studies to date of the common respiratory disease. Because the gene, called DENND1B, affects cells and signaling ...
Research yields new agent for some drug-resistant non-small cell lung cancers
Dec 23, 2009 |
5 / 5 (1) |
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The ability to make, test, and map the atomic structure of new anti-cancer agents has enabled a team of Dana-Farber Cancer Institute scientists to discover a compound capable of halting a common type of drug-resistant ...
Bees show off the perfect landing
Dec 23, 2009 |
4.6 / 5 (7) |
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(PhysOrg.com) -- Honey bees undergo a sudden transition from speeding aircraft to hovering helicopter as they perform the delicate art of landing on a flower.
Study shows a key protein helps control blood pressure
Dec 23, 2009 |
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University of Iowa researchers have shown that a protein channel helps nerve sensors in blood vessels keep blood pressure in check. Without the protein channel, known as ASIC2, the sensors are unable to send the brain the ...
How do you improve mammogram accuracy? Add noise
Technology / Computer Sciences
Dec 22, 2009 |
5 / 5 (1) |
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Members of a Syracuse University research team have shown that an obscure phenomenon called stochastic resonance (SR) can improve the clarity of signals in systems such as radar, sonar and even radiography, used in medical ...
How nurses can better support families of dying children
Dec 22, 2009 |
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Most nurses that work in a children's critical care unit feel prepared and trained to help parents during the final moments of their child's life and the difficult hours that follow.
We now know that the brain controls the formation of bone
Dec 22, 2009 |
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The brain acts as a profound regulatory centre, controlling myriad processes throughout the body in ways we are only just beginning to understand. In new findings, Australian scientists have shown surprising connections between ...
Researchers crack part of the neuronal code
Medicine & Health / Neuroscience
Dec 22, 2009 |
4.9 / 5 (7) |
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(PhysOrg.com) -- Prostheses for paralysed patients, communication with patients who have lost all capacity for normal communication - the hopes for modern brain research are high. However, such brain-machine ...
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