Information about Carrier Wave
In telecommunications, a carrier wave, or carrier is a waveform (usually sinusoidal) that is modulated (modified) with an input signal for the purpose of conveying information, for example voice or data, to be transmitted. This carrier wave is usually of much higher frequency than the baseband modulating signal (the signal which contains the information).
Carrier waves are used when transmitting radio signals to a radio receiver.
Source: mostly from Federal Standard 1037C and from MIL-STD-188
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Synonyms (in ancient Greek, συν ("syn") = plus and όνομα ("onoma") = name
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Carrier waves are used when transmitting radio signals to a radio receiver.
- Frequency modulation (FM) and amplitude modulation (AM) are common methods of sending information over carrier waves.
- In the case of single-sideband modulation (SSB) the carrier is suppressed (and in some forms of SSB eliminated). The carrier must be reintroduced at the receiver by a beat frequency oscillator (BFO).
Modern modulation systems & the carrier wave
Newer forms of radio communication, such as spread spectrum and ultra wide band, do not transmit a conventional carrier wave, nor does COFDM, which is used in DSL and in the European standard for HDTV.- COFDM should be thought of as an array of symmetrical carrier waves. The rules governing carrier wave propagation affect COFDM differently than 8VSB.
- Some forms of spread spectrum transmission and most forms of ultra wide band transmission are mathematically defined as being devoid of carrier waves.
Definition of carrier waves
In telecommunication, the term carrier (cxr) or carrier wave has the following meanings:- A waveform suitable for modulation by an information-bearing signal.
- An unmodulated emission. Note: The carrier is usually a sinusoidal wave or a uniform or predictable series of pulses. Synonym: carrier wave.
- Sometimes employed as a synonym for a carrier system, or a synonym for a telecommunications provider company (operator), such as a common carrier.
Source: mostly from Federal Standard 1037C and from MIL-STD-188
References
See also
Telecommunication is the transmission of signals over a distance for the purpose of communication. In modern times, this process typically involves the sending of electromagnetic waves by electronic transmitters, but in earlier times telecommunication may have involved the use of
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Waveform means the shape and form of a signal such as a wave moving in a solid, liquid or gaseous medium.
In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form.
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In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form.
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sine wave or sinusoid is a function that occurs often in mathematics, physics, signal processing, electrical engineering, and many other fields. Its most basic form is:
which describes a wavelike function of time (t) with
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which describes a wavelike function of time (t) with
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- For the musical use of "modulation" as a change of key, see modulation (music).
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In telecommunications, transmission is the forwarding of signal traffic over distances that are too great to be simply connected by a twisted pair wires. Techniques available now may be microwave link, satellite link, coaxial cable or fibre optic cable.
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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Baseband is an adjective that describes signals and systems whose range of frequencies is measured from 0 to a maximum bandwidth or highest signal frequency; it is sometimes used as a noun for a band of frequencies starting at 0.
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signal is any time-varying quantity. Signals are often scalar-valued functions of time (waveforms), but may be vector valued and may be functions of any other relevant independent variable.
The concept is broad, and hard to define precisely.
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The concept is broad, and hard to define precisely.
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Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.
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frequency modulation (FM) conveys information over a carrier wave by varying its frequency (contrast this with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant).
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Amplitude modulation (AM) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent.
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Single-sideband modulation (SSB) is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth. It is closely related to vestigial sideband modulation (VSB) (see below).
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A beat frequency oscillator or BFO in radio telegraphy, is a dedicated oscillator used to create an audio frequency signal from carrier wave transmissions to make them audible, as they are not broadcast as such.
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center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies. It is usually defined as either the arithmetic mean or the geometric mean of the lower cutoff frequency and the upper cutoff frequency of a band-pass system
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Spread-spectrum techniques are methods by which energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.
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Ultra-wideband (UWB, ultra-wide band, ultraband, etc.) is a radio technology that can be used for short-range high-bandwidth communications by using a large portion of the radio spectrum in a way that doesn't interfere with other more traditional 'narrow band'
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DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, although in recent years, many have adopted digital subscriber line
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High-definition television (HDTV) is a digital television broadcasting system with a significantly higher resolution than traditional formats (NTSC, SECAM, PAL). While some early analog HDTV formats were broadcast in Europe and Japan, HDTV is usually broadcast digitally,
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8VSB is the 8-level vestigial sideband modulation method adopted for terrestrial broadcast of the ATSC digital television standard in the United States, Canada, and other countries.
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Throughput
In the 6 MHz (megahertz) channel used for broadcast ATSC, 8VSB carries 19...... Click the link for more information.
Spread-spectrum techniques are methods by which energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth.
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Ultra-wideband (UWB, ultra-wide band, ultraband, etc.) is a radio technology that can be used for short-range high-bandwidth communications by using a large portion of the radio spectrum in a way that doesn't interfere with other more traditional 'narrow band'
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Telecommunication is the transmission of signals over a distance for the purpose of communication. In modern times, this process typically involves the sending of electromagnetic waves by electronic transmitters, but in earlier times telecommunication may have involved the use of
..... Click the link for more information.
..... Click the link for more information.
Waveform means the shape and form of a signal such as a wave moving in a solid, liquid or gaseous medium.
In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form.
..... Click the link for more information.
In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form.
..... Click the link for more information.
- For the musical use of "modulation" as a change of key, see modulation (music).
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Information is the result of processing, gathering, manipulating and organizing data in a way that adds to the knowledge of the receiver. In other words, it is the context in which data is taken.
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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
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- The use of signals for controlling communications.
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In physics, emission is the process by which the energy of a photon is released by another entity, for example, by an atom whose electrons make a transition between two electronic energy levels. The photon is created in the process.
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sine wave or sinusoid is a function that occurs often in mathematics, physics, signal processing, electrical engineering, and many other fields. Its most basic form is:
which describes a wavelike function of time (t) with
..... Click the link for more information.
which describes a wavelike function of time (t) with
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For the taxonomical term, see .
Synonyms (in ancient Greek, συν ("syn") = plus and όνομα ("onoma") = name
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In telecommunication, a carrier system (loosely, a synonym with carrier) is a multichannel telecommunications system in which a number of individual circuits (data, voice, or combination thereof) are multiplexed for transmission between nodes of a network.
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