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Analog devices are a combination of both analog machine and analog media that can together measure, record, reproduce, receive or broadcast continuous information, for example, the almost infinite number of grades of transparency, voltage, resistance, rotation, or pressure. [1] In theory, the continuous information in an analog signal has an infinite number of possible values with the only limitation on resolution being the accuracy of the analog device.
Analog media are materials with analog properties, such as photographic film, which are used in analog devices, such as cameras.
There are notable non-electrical analog devices, such as some clocks (sundials, water clocks), the astrolabe, slide rules, the governor of a steam engine, the planimeter (a simple device that measures the surface area of a closed shape), Kelvin's mechanical tide predictor, acoustic rangefinders, servomechanisms (e.g. the thermostat), a simple mercury thermometer, a weighing scale, and the speedometer.
The telautograph is an analogue precursor to the modern fax machine. It transmits electrical impulses recorded by potentiometers to stepping motors attached to a pen, thus being able to reproduce a drawing or signature made by the sender at the receiver's station. It was the first such device to transmit drawings to a stationary sheet of paper; previous inventions in Europe used rotating drums to make such transmissions.
An analog synthesizer is a synthesizer that uses analog circuits and analog computer techniques to generate sound electronically.
The analog television encodes television and transports the picture and sound information as an analog signal, that is, by varying the amplitude and/or frequencies of the broadcast signal. All systems preceding digital television, such as NTSC, PAL, and SECAM are analog television systems.
An analog computer is a form of computer that uses electrical, mechanical, or hydraulic phenomena to model the problem being solved. More generally an analog computer uses one kind of physical quantity to represent the behavior of another physical system, or mathematical function. Modeling a real physical system in a computer is called simulation.
The chemical reactions in photographic film and film stock involve analog processes, with camera as machinery.
In electronics, a digital-to-analog converter is a circuit for converting a digital signal (usually binary) to an analog signal (current, voltage or electric charge). Digital-to-analog converters are interfaces between the digital world and analog worlds. An analog-to-digital converter is an electronic circuit that converts continuous signals to discrete digital numbers.
An analog signal or analogue signal is any continuous-time signal representing some other quantity, i.e., analogous to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies continuously with the pressure of the sound waves.
An analog computer or analogue computer is a type of computation machine (computer) that uses the continuous variation aspect of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude.
Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other electrically charged particles. It is a subfield of physics and electrical engineering which uses active devices such as transistors, diodes, and integrated circuits to control and amplify the flow of electric current and to convert it from one form to another, such as from alternating current (AC) to direct current (DC) or from analog signals to digital signals.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays of several types.
In electronics, an analog-to-digital converter is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an analog input voltage or current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities.
A communications system or communication system is a collection of individual telecommunications networks systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperation to form an integrated whole. The components of a communications system serve a common purpose, are technically compatible, use common procedures, respond to controls, and operate in union.
In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significant, and usually undesired, factor in the design of almost all communications links.
Pulse-width modulation (PWM), also known as pulse-duration modulation (PDM) or pulse-length modulation (PLM), is any method of representing a signal as a rectangular wave with a varying duty cycle.
In electronics, a digital-to-analog converter is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function.
Signal refers to both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology.
This is an index of articles relating to electronics and electricity or natural electricity and things that run on electricity and things that use or conduct electricity.
In electronics, a sample and hold circuit is an analog device that samples the voltage of a continuously varying analog signal and holds its value at a constant level for a specified minimum period of time. Sample and hold circuits and related peak detectors are the elementary analog memory devices. They are typically used in analog-to-digital converters to eliminate variations in input signal that can corrupt the conversion process. They are also used in electronic music, for instance to impart a random quality to successively-played notes.
An integrator in measurement and control applications is an element whose output signal is the time integral of its input signal. It accumulates the input quantity over a defined time to produce a representative output.
The following outline is provided as an overview of and topical guide to electrical engineering.
Analogue electronics are electronic systems with a continuously variable signal, in contrast to digital electronics where signals usually take only two levels. The term analogue describes the proportional relationship between a signal and a voltage or current that represents the signal. The word analogue is derived from the Greek word ανάλογος analogos meaning proportional.
This is an alphabetical list of articles pertaining specifically to electrical and electronics engineering. For a thematic list, please see List of electrical engineering topics. For a broad overview of engineering, see List of engineering topics. For biographies, see List of engineers.
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electrical circuit. For a circuit to be referred to as electronic, rather than electrical, generally at least one active component must be present. The combination of components and wires allows various simple and complex operations to be performed: signals can be amplified, computations can be performed, and data can be moved from one place to another.
A digital signal is a signal that represents data as a sequence of discrete values; at any given time it can only take on, at most, one of a finite number of values. This contrasts with an analog signal, which represents continuous values; at any given time it represents a real number within a continuous range of values.
The following outline is provided as an overview of and topical guide to electronics:
This glossary of electrical and electronics engineering is a list of definitions of terms and concepts related specifically to electrical engineering and electronics engineering. For terms related to engineering in general, see Glossary of engineering.