Information On carrier wave

In telecommunications a carrier wave or carrier is a waveform (usually sinusoidal that is Modulation (modified) with an signal (electrical engineering) for the purpose of conveying information.lt;/ref> This carrier wave is usually of much higher frequency than the input signal. The purpose of the carrier is usually either to transmit the information through space as an electromagnetic wave (as in radio communication), or to allow several carriers at different frequencies to share a common physical transmission medium by frequency division multiplexing (as is used in, for example, a cable television system). Frequency modulation (FM) and amplitude modulation (AM) are commonly used methods to modulate the carrier. 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). The frequency for a given radio or television station is actually the carrier waves center frequency

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 Signalling (telecommunication) # An unmodulated Emission (electromagnetic radiation) Note: The carrier is usually a sine 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: Federal Standard 1037C and MIL-STD-188 lt;/small>

Carrierless modulation systems

Newer forms of radio communication, such as spread spectrum and ultra-wideband do not transmit a conventional carrier wave, nor does Orthogonal frequency-division multiplexing which is used in Digital subscriber line and in the European standard for High-definition television * Orthogonal frequency-division multiplexing should be thought of as an array of symmetrical carrier waves. The rules governing carrier wave propagation affect OFDM differently than 8VSB * Some forms of spread spectrum transmission and most forms of ultra-wideband transmission are mathematically defined as being devoid of carrier waves.

See also

* Carrier recovery * Carrier system * Carrier tone * Frequency-division multiplexing

References

Category:Communication circuits ca:Ona portadora da:Bærebølge de:Trägersignal es:Onda portadora fr:Porteuse ko:반송파 id:Gelombang pembawa it:Onda portante he:גל נושא ht:Onn pòtez nl:Draaggolf ja:搬送波 no:Bærebølge pl:Fala nośna pt:Portadora ru:Несущий сигнал sd:ڪانڌي لهر su:Gelombang pamawa fi:Kantoaalto sv:Bärvåg uk:Несний сигнал zh:载波

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