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In telecommunications, broadband is a wide bandwidth data transmission with an ability to simultaneously transport multiple signals and traffic types. The medium can be coaxial cable, optical fiber, radio or twisted pair.
Different criteria for "broad" have been applied in different contexts and at different times. Its origin is in physics, acoustics, and radio systems engineering, where it had been used with a meaning similar to "wideband". Later, with the advent of digital telecommunications, the term was mainly used for transmission over multiple channels. Whereas a passband signal is also modulated so that it occupies higher frequencies (compared to a baseband signal which is bound to the lowest end of the spectrum, see line coding), it is still occupying a single channel. The key difference is that what is typically considered a broadband signal in this sense is a signal that occupies multiple (non-masking, orthogonal) passbands, thus allowing for much higher throughput over a single medium but with additional complexity in the transmitter/receiver circuitry.
The term became popularized through the 1990s as a marketing term for Internet access that was faster than dialup access, the original Internet access technology, which was limited to 56 kbit/s. This meaning is only distantly related to its original technical meaning.
In telecommunications, a broadband signaling method is one that handles a wide band of frequencies. "Broadband" is a relative term, understood according to its context. The wider (or broader) the bandwidth of a channel, the greater the information-carrying capacity, given the same channel quality.
In radio, for example, a very narrow band will carry Morse code, a broader band will carry speech, and a still broader band will carry music without losing the high audio frequencies required for realistic sound reproduction. This broad band is often divided into channels or "frequency bins" using passband techniques to allow frequency-division multiplexing instead of sending a higher-quality signal.
A television antenna may be described as "broadband" because it is capable of receiving a wide range of channels, while a single-frequency or Lo-VHF antenna is "narrowband" since it receives only 1 to 5 channels. The U.S. federal standard FS-1037C defines "broadband" as a synonym for wideband.
In data communications a 56k modem will transmit a data rate of 56 kilobits per second (kbit/s) over a 4-kilohertz-wide telephone line (narrowband or voiceband). The various forms of digital subscriber line (DSL) services are broadband in the sense that digital information is sent over multiple channels. Each channel is at higher frequency than the baseband voice channel, so it can support plain old telephone service on a single pair of wires at the same time.
However, when that same line is converted to a non-loaded twisted-pair wire (no telephone filters), it becomes hundreds of kilohertz wide (broadband) and can carry up to 60 megabits per second using very-high-bitrate digital subscriber line (VDSL or VHDSL) techniques.
In computer networks
Many computer networks use a simple line code to transmit one type of signal using a medium's full bandwidth using its baseband (from zero through the highest frequency needed). Most versions of the popular Ethernet family are given names such as the original 1980s 10BASE5 to indicate this. Networks that use cable modems on standard cable television infrastructure are called broadband to indicate the wide range of frequencies that can include multiple data users as well as traditional television channels on the same cable. Broadband systems usually use a different radio frequency modulated by the data signal for each band. The total bandwidth of the medium is larger than the bandwidth of any channel.
The 10BROAD36 broadband variant of Ethernet was standardized by 1985, but was not commercially successful. The DOCSIS standard became available to consumers in the late 1990s, to provide Internet access to cable television residential customers. Matters were further confused by the fact that the 10PASS-TS standard for Ethernet ratified in 2008 used DSL technology, and both cable and DSL modems often have Ethernet connectors on them.
Power lines have also been used for various types of data communication. Although some systems for remote control are based on narrowband signaling, modern high-speed systems use broadband signaling to achieve very high data rates. One example is the ITU-T G.hn standard, which provides a way to create a local area network up to 1 Gigabit/s (which is considered high-speed as of 2014) using existing home wiring (including power lines, but also phone lines and coaxial cables).
"Broadband" in analog video distribution is traditionally used to refer to systems such as cable television, where the individual channels are modulated on carriers at fixed frequencies. In this context, baseband is the term's antonym, referring to a single channel of analog video, typically in composite form with separate baseband audio. The act of demodulating converts broadband video to baseband video. Fiber optic allows the signal to be transmitted farther without being repeated. Cable companies use a hybrid system using fiber to transmit the signal to neighborhoods and then changes the signal from light to radio frequency to be transmitted to over coaxial cable to homes. Doing so reduces the use of having multiple head ends. A head end gathers all the information from the local cable networks and movie channels and then feeds the information into the system.
A range of more precise definitions of speed have been prescribed at times, including:
- "Greater than the primary rate" (which ranged from about 1.5 to 2 Mbit/s) - CCITT in "broadband service" in 1988.
- "Internet access that is always on and faster than the traditional dial-up access", - US National Broadband Plan of 2009
- 4 Mbit/s down, 1 Mbit/s up - FCC, 2010
- 25 Mbit/s down, 3 Mbit/s up - FCC, 2015
In 2014, researchers at Korea Advanced Institute of Science and Technology made developments on the creation of ultra-shallow broadband optical instruments.
- Broadband mapping in the United States
- National broadband plans from around the world
- List of Broadband Providers in the US
- List of Broadband Providers in Malaysia
- Keith Attenborough (1988). "Review of ground effects on outdoor sound propagation from continuous broadband sources". Applied Acoustics 24 (4): 289–319. doi:10.1016/0003-682X(88)90086-2.
- John P. Shanidin (September 9, 1949). "Antenna". US Patent 2,533,900. Issued December 12, 1950.
- "Definition: broadband". Federal Standard 1037C, Glossary of Telecommunication Terms. 1996. Retrieved July 19, 2011.
- "Broadband - Define Broadband at Dictionary.com". Dictionary.com.
- Ender Ayanoglu; Nail Akar. "B-ISDN (Broadband Integrated Services Digital Network)". Center for Pervasive Communications and Computing, UC Irvine. Retrieved July 12, 2011.
- Carl Stephen Clifton (1987). What every engineer should know about data communications. CRC Press. p. 64. ISBN 978-0-8247-7566-7.
Broadband: Modulating the data signal onto an RF carrier and applying this RF signal to the carrier media
- Mary Louise Hollowell (1983). The cable/broadband communications books 3. Knowledge Industry Publications. p. 64. ISBN 978-0-86729-042-4.
Broadband: relative term referring to a systemm which carries a wide frequency range.
- "802.3b-1985 – Supplement to 802.3: Broadband Medium Attachment Unit and Broadband Medium Specifications, Type 10BROAD36 (Section 11)". IEEE Standards Association. 1985. Retrieved July 12, 2011.
- Paula Musich (July 20, 1987). "Broadband user share pains, gains". Network World. pp. 1, 8. Retrieved July 14, 2011.
Broadband networks employ frequency-division multiplexing to divide coaxial cable into separate channels, each of which serves as an individual local network.
- "HTI+ Home Technology Integration and CEDIA Installer I All-in-One Exam Guide". google.co.uk.
- "Transmitting video over structured cabling systems". cablinginstall.com.
- Mark Sweney. "BT Vision boasts 150,000 customers". the Guardian.
- "What is Broadband?". The National Broadband Plan. US Federal Communications Commission. Retrieved July 15, 2011.
- Jeffrey A. Hart; Robert R. Reed; François Bar (November 1992). "The building of the internet: Implications for the future of broadband networks". Telecommunications Policy 16 (8): 666–689. doi:10.1016/0308-5961(92)90061-S.
- "Recommendation I.113, Vocabulary of Terms for Broadband aspects of ISDN". ITU-T. June 1997. Retrieved 19 July 2011.
- "Inquiry Concerning the Deployment of Advanced Telecommunications Capability to All Americans in a Reasonable and Timely Fashion, and Possible Steps to Accelerate Such Deployment Pursuant to Section 706 of the Telecommunications Act of 1996, as Amended by the Broadband Data Improvement Act" (PDF). GN Docket No. 10-159, FCC-10-148A1. Federal Communications Commission. August 6, 2010. Retrieved July 12, 2011.
- "FCC Changes Definition of Broadband".
- Ruiz, Rebecca R. (March 12, 2015). "F.C.C. Sets Net Neutrality Rules". New York Times. Retrieved March 13, 2015.
- Sommer, Jeff (March 12, 2015). "What the Net Neutrality Rules Say". New York Times. Retrieved March 13, 2015.
- FCC Staff (March 12, 2015). "Federal Communications Commission - FCC 15-24 - In the Matter of Protecting and Promoting the Open Internet - GN Docket No. 14-28 - Report and Order on Remand, Declaratory Ruling, and Order" (PDF). Federal Communications Commission. Retrieved March 13, 2015.
- Reisinger, Don (April 13, 2015). "Net neutrality rules get published -- let the lawsuits begin". CNET. Retrieved April 13, 2015.
- Federal Communications Commission (April 13, 2015). "Protecting and Promoting the Open Internet - A Rule by the Federal Communications Commission on 04/13/2015". Federal Register. Retrieved April 13, 2015.
- Broadband and ultrathin polarization manipulators developed Phys.org, December 4, 2014