signal
Quick Summary
Signals are a fundamental aspect of communication, existing independently of spoken or written language. They function by interrupting a constant energy transfer, such as the dots and dashes in a telegraph circuit, to attract attention and convey meaning. These interruptions can occur naturally, like a pencil tapping in a quiet room, or be man-made.1
While signals themselves may have a limited direct meaning, they can be coded to refer to language, greatly expanding their communicative potential. In telecommunications, signals are crucial for transmitting information. They can be analog, like voice signals, or digital, representing information as binary numbers. Modulation is a key process where a characteristic of a carrier wave is altered according to an information signal, allowing it to travel through a transmission medium. This process is essential for fitting signals to specific communication channels and enabling multiple users to share a channel without interference.1234
- communication - Signals
- communication - Signs
- telecommunication - Analog modulation
- telecommunication - Phase-shift keying
- signal
- signal
- radio technology - Radio noise, fading, and interference
- animal communication - Senders and receivers
- integrated circuit - Digital signal processors
- animal communication - Signal transmission
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military intelligenceSignalsGained from intercepting, processing, and analyzing foreign electrical communications and other signals, signals intelligence (often called SIGINT) comprises three elements: communications, electronics, and telemetry.
Read MoreGained from intercepting, processing, and analyzing foreign electrical communications and other signals, signals intelligence (often called SIGINT) comprises three elements: communications, electronics, and telemetry.
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railroadSignalingRailroad signals are a form of communication designed to inform the train crew, particularly the engine crew, of track conditions ahead and to tell it how to operate the train.
Read MoreRailroad signals are a form of communication designed to inform the train crew, particularly the engine crew, of track conditions ahead and to tell it how to operate the train.
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traffic controlHistory…developed slowly with the first signalman, or “railway policeman,” located at passenger and goods depots, or stations, sited along the line. These men indicated, by means of hand signals, the state of the track ahead. Red taillights were mounted at the rear of trains at night to improve safety. Later,…
Read More…developed slowly with the first signalman, or “railway policeman,” located at passenger and goods depots, or stations, sited along the line. These men indicated, by means of hand signals, the state of the track ahead. Red taillights were mounted at the rear of trains at night to improve safety. Later,…
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semaphoresignaling, usually by means of flags or lights. Before the invention of the telegraph, semaphore signaling from high towers was used to transmit messages between distant points. One such system was developed by Claude Chappe in France in 1794, employing a set of arms that…
Read Moresignaling, usually by means of flags or lights. Before the invention of the telegraph, semaphore signaling from high towers was used to transmit messages between distant points. One such system was developed by Claude Chappe in France in 1794, employing a set of arms that…
Read More- military communication
transmission of information from reconnaissance and other units in contact with the enemy and the means for exercising command by the transmission of orders and instructions of commanders to their subordinates. As such, it comprises all means of transmitting messages, orders, and reports, both in…
Read Moretransmission of information from reconnaissance and other units in contact with the enemy and the means for exercising command by the transmission of orders and instructions of commanders to their subordinates. As such, it comprises all means of transmitting messages, orders, and reports, both in…
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telecommunicationAnalog modulation…in proportion to the information signal. The other technique, called frequency modulation, varies the frequency of a fixed-amplitude carrier wave in proportion to the information signal.
Read More…in proportion to the information signal. The other technique, called frequency modulation, varies the frequency of a fixed-amplitude carrier wave in proportion to the information signal.
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telegraphSignal processing and transmissionSoon after its introduction in Europe it became apparent that the American Morse Code was inadequate for the transmission of much non-English text because it lacked letters with diacritical marks. A variant that ultimately became known as the International Morse Code…
Read MoreSoon after its introduction in Europe it became apparent that the American Morse Code was inadequate for the transmission of much non-English text because it lacked letters with diacritical marks. A variant that ultimately became known as the International Morse Code…
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telephonePush-button dialingThis signal is translated into a digit at the local office.
Read MoreThis signal is translated into a digit at the local office.
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modem…devices that convert digital data signals into modulated analog signals suitable for transmission over analog telecommunications circuits. A modem also receives modulated signals and demodulates them, recovering the digital signal for use by the data equipment. Modems thus make it possible for established telecommunications media to support a wide variety…
Read More…devices that convert digital data signals into modulated analog signals suitable for transmission over analog telecommunications circuits. A modem also receives modulated signals and demodulates them, recovering the digital signal for use by the data equipment. Modems thus make it possible for established telecommunications media to support a wide variety…
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materials scienceMaterials for computers and communications…information in the form of signals representing data, speech, sound, documents, and visual images. These signals are created, transmitted, and processed as moving electrons or photons, and so the basic materials groups involved are classified as electronic and photonic. In some cases, materials known as optoelectronic bridge these two classes,…
Read More…information in the form of signals representing data, speech, sound, documents, and visual images. These signals are created, transmitted, and processed as moving electrons or photons, and so the basic materials groups involved are classified as electronic and photonic. In some cases, materials known as optoelectronic bridge these two classes,…
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