Carrier system

<p>A carrier system is a <a href="/facts/Communications_system/5t3Ys2DI">communications system</a> that <a href="/facts/Transmission_(telecommunications)/33zk8a0A">transmits</a> information, such as the voice signals of a <a href="/facts/Telephone_call/4wUtUXpY">telephone call</a> and the video signals of <a href="/facts/Television/X4YG5nT1">television</a>, by modulation of one or multiple <a href="/facts/Carrier_signal/ae98pBlY">carrier signals</a> above the principal voice frequency or data rate.
</p><p>Carrier systems typically transmit multiple channels of communication simultaneously over the <a href="/facts/Shared_medium/7BPrQ65Q">shared medium</a> using various forms of <a href="/facts/Multiplexing/YE7hK8cw">multiplexing</a>. Prominent multiplexing methods of the <a href="/facts/Carrier_signal/ae98pBlY">carrier signal</a> are <a href="/facts/Time-division_multiplexing/tv7bMh1v">time-division multiplexing</a> (TDM) and <a href="/facts/Frequency-division_multiplexing/lgj6TMU1">frequency-division multiplexing</a> (FDM). A <a href="/facts/Cable_television_system/GzXa4pbW">cable television system</a> is an example of frequency-division multiplexing. Many television programs are carried simultaneously on the same <a href="/facts/Coaxial_cable/aG9FfCpL">coaxial cable</a> by sending each at a different frequency. Multiple layers of multiplexing may ultimately be performed upon a given input <a href="/facts/Signal/41YqUJ8c">signal</a>. For example, in the <a href="/facts/Public_switched_telephone_network/eVrCTDU7">public switched telephone network</a>, many telephone calls are sent over shared trunk lines by time-division multiplexing. For long-distance calls several of these channels may be sent over a <a href="/facts/Communications_satellite/y5RXPMDT">communications satellite</a> link by frequency-division multiplexing. At a given receiving <a href="/facts/Node_(networking)/LBp2vNcJ">node</a>, specific channels may be demultiplexed individually.
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Carrier system open-in-new

Carrier system