Simulcast
Encyclopedia
Simulcast, shorthand for "simultaneous broadcast", refers to programs or events broadcast
across more than one medium
, or more than one service on the same medium, at the same time. For example, Absolute Radio is simulcast on both AM and on satellite radio
, and the BBC
's Prom
concerts are often simulcast on both BBC Radio 3
and BBC Television
. Another application is the transmission of the original-language soundtrack
of movies or TV series over local or Internet radio
, with the television broadcast having been dubbed
into a local language.
's London Rainbow Concert simultaneously on BBC2 TV and Radio 2 (see It's Too Late To Stop Now
).
Similarly, in the 1980s, before Multichannel Television Sound, or home theater was commonplace in American households, broadcasters would air a high fidelity version of a television program's audio portion over FM stereo simultaneous with the television broadcast. PBS stations were the most likely, especially when airing a live concert. It was also a way of allowing MTV
and similar music channels to run stereo sound through the cable-TV network. This method required a stereo FM transmitter modulating MTV's stereo soundtrack through the cable-TV network and customers connecting their FM receiver's antenna input to the cable-TV outlet. Then they would tune the FM receiver to the specified frequency that would be published in documentation supplied by the cable-TV provider.
The first ever concert "simulcast" was Frank Zappa
's Halloween shows (October 31, 1981), live from NYC's Palladium and shown on MTV
with the audio-only portion simulcast over the FM "Starfleet Radio" network. A later, notable application for simulcasting in this context was the Live Aid
telethon concert that was broadcast around the world on July 13, 1985. Most destinations where this concert was broadcast had the concert simulcast by at least one TV network and at least one of the local FM stations.
Most stereo-capable video recorders made through the 1980s and early 1990s had a "simulcast" recording mode where they recorded video signals from the built-in TV tuner and audio signals from the VCR's audio line-in connectors. This was to allow one to connect a stereo FM tuner that is tuned to the simulcast frequency to the VCR's audio input in order to record the stereo sound of a TV program that would otherwise be recorded in mono. The function was primarily necessary with stereo VCRs that didn't have a stereo TV tuner or were operated in areas where stereo TV broadcasting wasn't in place. This was typically selected through the user setting the input selector to "Simulcast" or "Radio" mode or, in the case of some JVC units, the user setting another "audio input" switch from "TV" or "Tuner" to "Line".
In the mid to late 1990s, video game developer Nintendo
utilized simulcasting to provide enhanced orchestral scoring and voice-acting for the first ever "integrated radio-games" – its Satellaview
video games. Whereas digital game data was broadcast to the Satellaview unit to provide the basic game and game sounds, Nintendo's partner, satellite radio company St.GIGA
, simultaneously broadcast the musical and vocal portion of the game via radio. These two streams were combined at the Satellaview to provide a unified audiotrack analagous to stereo.
During National Party rule in South Africa, many programs were dubbed in Afrikaans. The English soundtrack was available on Radio 2000. This could be selected using a button labeled simulcast on many televisions manufactured before 1995.
Radio programs have been simulcast on television since the invention thereof; however, as of recent, perhaps the most visible example of radio shows on television is The Howard Stern Show, which currently airs on SIRIUS Satellite Radio as well as Howard TV. Another prominent radio show that is simulcast on television is Imus in the Morning
, which airs on RFD-TV
in addition to Citadel Media. In wrestling the first simulcast happened on March 26, 2001 between WWF Raw is War and WCW Nitro.
In another case, popular programs will be aired simultaneously on different services in adjacent countries, such as The Simpsons
, airing Sunday evenings at 8:00 p.m. (Eastern and Pacific times) on both Fox
in the United States
and Global
in Canada
. "Simulcast" is often a colloquial term for the related Canadian practice of simultaneous substitution
(simsub).
In sports, simulcasts are when a single announcer broadcasts play-by-play coverage both over television and radio. The practice was common in the early years of television, but since the 1980s, most teams have used a separate team for television and for radio.
As all NFL
television broadcasts are done by the national networks or via cable, there are no regular TV-to-radio football simulcasts. However, NFL rules require that games airing on cable and satellite networks (ESPN
, NFL Network
) are simulcast on local over-air TV stations in markets serving the two local teams participating in each game.
Similarly, no current National Basketball Association
teams use a simulcast. Al McCoy
(Phoenix
), Chick Hearn
(Los Angeles Lakers
), Kevin Calabro
(Seattle
) and Rod Hundley
(Utah
) were the last NBA team broadcasters to simulcast.
In Major League Baseball
, only Vin Scully
continues the practice; however, he simulcasts only the first three innings of Los Angeles Dodgers
games at Dodger Stadium
and other National League
Western Division parks.
The practice is most prevalent in the National Hockey League
where three teams simulcast:
Simulcasts via satellite
can be a challenge, as there is a significant delay
because of the distance
- nearly 50000 miles (80,467 km) round-trip - involved. Anything involving video compression (and to some extent audio data compression) also has an additional significant delay, which is noticeable when watching local TV stations on direct broadcast satellite
s. Even though the process is not instantaneous, this is still considered a simulcast because it is not intentionally stored anywhere.
(Multiplexing
-- also sometimes called "multicasting" -- is something of a reversal of this situation, where multiple program streams are combined into a single broadcast. The two terms are sometimes confused.)
In horse racing, a simulcast is a broadcast of a horse race which allows wagering
at two or more sites; the simulcast often involves the transmission of wagering information to a central site, so that all bettors may bet in the same betting pool, as well as the broadcast of the race.
The San Francisco Giants
simulcast with the Oakland Athletics
while playing each other on their respective stations and commercials with a mix of broadcasters from both teams.
On cable television
systems, analog-digital simulcasting (ADS) means that analog channels are duplicated as digital subchannel
s. Digital tuners are programmed to use the digital subchannel instead of the analog. This allows for smaller, cheaper cable boxes by eliminating the analog tuner and some analog circuitry. On DVR
s, it eliminates the need for an MPEG encoder to convert the analog signal to digital for recording. The primary advantage is the elimination of interference, and as analog channels are dropped, the ability to put 10 or more SDTV (or two HDTV, or various other combinations) channels in its place. The primary drawback is the common problem of over-compression (quantity over quality) resulting in fuzzy pictures and pixelation
.
In universities with multiple campuses, simulcasting may be used for a single teacher to teach class to students in two or more locations at the same time, using videoconferencing
equipment.
In many public safety agencies, simulcast refers to the broadcasting of the same transmission on the same frequency from multiple towers either simultaneously, or offset by a fixed number of microseconds. This allows for a larger coverage area without the need for a large number of channels, resulting in increased spectral efficiency
. This comes at the cost of overall poorer voice quality, as multiple sources increase multipath interference
significantly, resulting in what is called simulcast distortion.
With some of the latest Simulcast control equipment for FM radio networks, the distortion experienced is almost in-audible to the human ear. With the introduction of Line Equalisation Modules and Tone Generation Modules, the phasing advance and retard is so well calculated that the distortion is almost entirely averted.
The Tone Generation Module (or TGM) generates a pilot tone at 3300 Hz which is then sampled by the Line Equalisation Module (or LEM) which each channel on each radio high site has 2 of located back at the main control site. This then determines the phase shift in the signal and adjusts the transmission accordingly such that all the overlap areas in transmission are in phase with each other.
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
across more than one medium
Mass media
Mass media refers collectively to all media technologies which are intended to reach a large audience via mass communication. Broadcast media transmit their information electronically and comprise of television, film and radio, movies, CDs, DVDs and some other gadgets like cameras or video consoles...
, or more than one service on the same medium, at the same time. For example, Absolute Radio is simulcast on both AM and on satellite radio
Satellite radio
Satellite radio is an analogue or digital radio signal that is relayed through one or more satellites and thus can be received in a much wider geographical area than terrestrial FM radio stations...
, and the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
's Prom
The Proms
The Proms, more formally known as The BBC Proms, or The Henry Wood Promenade Concerts presented by the BBC, is an eight-week summer season of daily orchestral classical music concerts and other events held annually, predominantly in the Royal Albert Hall in London...
concerts are often simulcast on both BBC Radio 3
BBC Radio 3
BBC Radio 3 is a national radio station operated by the BBC within the United Kingdom. Its output centres on classical music and opera, but jazz, world music, drama, culture and the arts also feature. The station is the world’s most significant commissioner of new music, and its New Generation...
and BBC Television
BBC Television
BBC Television is a service of the British Broadcasting Corporation. The corporation, which has operated in the United Kingdom under the terms of a Royal Charter since 1927, has produced television programmes from its own studios since 1932, although the start of its regular service of television...
. Another application is the transmission of the original-language soundtrack
Soundtrack
A soundtrack can be recorded music accompanying and synchronized to the images of a motion picture, book, television program or video game; a commercially released soundtrack album of music as featured in the soundtrack of a film or TV show; or the physical area of a film that contains the...
of movies or TV series over local or Internet radio
Internet radio
Internet radio is an audio service transmitted via the Internet...
, with the television broadcast having been dubbed
Dubbing (filmmaking)
Dubbing is the post-production process of recording and replacing voices on a motion picture or television soundtrack subsequent to the original shooting. The term most commonly refers to the substitution of the voices of the actors shown on the screen by those of different performers, who may be...
into a local language.
Simulcasting to provide stereo sound for TV broadcasts
Before stereo TV sound transmission was possible, simulcasting on TV and Radio was a method of effectively transmitting "stereo" sound to music TV broadcasts. The first such transmission was in 1974, when the BBC broadcast a recording of Van MorrisonVan Morrison
Van Morrison, OBE is a Northern Irish singer-songwriter and musician. His live performances at their best are regarded as transcendental and inspired; while some of his recordings, such as the studio albums Astral Weeks and Moondance, and the live album It's Too Late to Stop Now, are widely...
's London Rainbow Concert simultaneously on BBC2 TV and Radio 2 (see It's Too Late To Stop Now
It's Too Late to Stop Now
It's Too Late to Stop Now is a live album by Northern Irish singer-songwriter Van Morrison, released in 1974 . Frequently named as one of the best live albums ever recorded, It's Too Late to Stop Now was recorded during what has often been said to be Morrison's greatest phase as a live...
).
Similarly, in the 1980s, before Multichannel Television Sound, or home theater was commonplace in American households, broadcasters would air a high fidelity version of a television program's audio portion over FM stereo simultaneous with the television broadcast. PBS stations were the most likely, especially when airing a live concert. It was also a way of allowing MTV
MTV
MTV, formerly an initialism of Music Television, is an American network based in New York City that launched on August 1, 1981. The original purpose of the channel was to play music videos guided by on-air hosts known as VJs....
and similar music channels to run stereo sound through the cable-TV network. This method required a stereo FM transmitter modulating MTV's stereo soundtrack through the cable-TV network and customers connecting their FM receiver's antenna input to the cable-TV outlet. Then they would tune the FM receiver to the specified frequency that would be published in documentation supplied by the cable-TV provider.
The first ever concert "simulcast" was Frank Zappa
Frank Zappa
Frank Vincent Zappa was an American composer, singer-songwriter, electric guitarist, record producer and film director. In a career spanning more than 30 years, Zappa wrote rock, jazz, orchestral and musique concrète works. He also directed feature-length films and music videos, and designed...
's Halloween shows (October 31, 1981), live from NYC's Palladium and shown on MTV
MTV
MTV, formerly an initialism of Music Television, is an American network based in New York City that launched on August 1, 1981. The original purpose of the channel was to play music videos guided by on-air hosts known as VJs....
with the audio-only portion simulcast over the FM "Starfleet Radio" network. A later, notable application for simulcasting in this context was the Live Aid
Live Aid
Live Aid was a dual-venue concert that was held on 13 July 1985. The event was organized by Bob Geldof and Midge Ure to raise funds for relief of the ongoing Ethiopian famine. Billed as the "global jukebox", the event was held simultaneously in Wembley Stadium in London, England, United Kingdom ...
telethon concert that was broadcast around the world on July 13, 1985. Most destinations where this concert was broadcast had the concert simulcast by at least one TV network and at least one of the local FM stations.
Most stereo-capable video recorders made through the 1980s and early 1990s had a "simulcast" recording mode where they recorded video signals from the built-in TV tuner and audio signals from the VCR's audio line-in connectors. This was to allow one to connect a stereo FM tuner that is tuned to the simulcast frequency to the VCR's audio input in order to record the stereo sound of a TV program that would otherwise be recorded in mono. The function was primarily necessary with stereo VCRs that didn't have a stereo TV tuner or were operated in areas where stereo TV broadcasting wasn't in place. This was typically selected through the user setting the input selector to "Simulcast" or "Radio" mode or, in the case of some JVC units, the user setting another "audio input" switch from "TV" or "Tuner" to "Line".
In the mid to late 1990s, video game developer Nintendo
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
utilized simulcasting to provide enhanced orchestral scoring and voice-acting for the first ever "integrated radio-games" – its Satellaview
Satellaview
The is a satellite modem add-on for Nintendo's Super Famicom system that was released in Japan in 1995. Available for pre-release orders as early as February 13, 1995, the Satellaview retailed for between ¥14,000 and 18,000 and came bundled with the BS-X Game Pak and an 8M Memory Pak.The...
video games. Whereas digital game data was broadcast to the Satellaview unit to provide the basic game and game sounds, Nintendo's partner, satellite radio company St.GIGA
St.GIGA
is the name of a defunct satellite radio company that was formed as a subsidiary of satellite television company WOWOW and later became semi-independent, forming a keiretsu with its parent. Using the BS network to broadcast digital radio via direct broadcast satellite as a test on November 30,...
, simultaneously broadcast the musical and vocal portion of the game via radio. These two streams were combined at the Satellaview to provide a unified audiotrack analagous to stereo.
Other uses
In America, simulcast most often refers to the practice of offering the same programming on an FM and AM station owned by the same entity, in order to cut costs. With the advent of solid state AM transmitters and computers, it has become very easy for AM stations to broadcast a different format without additional cost; therefore, simulcast between FM/AM combos is rarely heard today. Normally, AM stations broadcast some type of talk format; depending on the population, the format may be ethnic.During National Party rule in South Africa, many programs were dubbed in Afrikaans. The English soundtrack was available on Radio 2000. This could be selected using a button labeled simulcast on many televisions manufactured before 1995.
Radio programs have been simulcast on television since the invention thereof; however, as of recent, perhaps the most visible example of radio shows on television is The Howard Stern Show, which currently airs on SIRIUS Satellite Radio as well as Howard TV. Another prominent radio show that is simulcast on television is Imus in the Morning
Imus in the Morning
Imus in the Morning is an American radio show hosted by Don Imus on Cumulus Media Networks , and simulcast for television on Fox Business Network....
, which airs on RFD-TV
RFD-TV
RFD-TV, or Rural Free Delivery TV, is a United States satellite and cable television channel devoted to rural issues, concerns, and interests. The channel's name is a reference to Rural Free Delivery, the name for the United States Postal Service's system of delivering mail directly to rural patrons...
in addition to Citadel Media. In wrestling the first simulcast happened on March 26, 2001 between WWF Raw is War and WCW Nitro.
In another case, popular programs will be aired simultaneously on different services in adjacent countries, such as The Simpsons
The Simpsons
The Simpsons is an American animated sitcom created by Matt Groening for the Fox Broadcasting Company. The series is a satirical parody of a middle class American lifestyle epitomized by its family of the same name, which consists of Homer, Marge, Bart, Lisa and Maggie...
, airing Sunday evenings at 8:00 p.m. (Eastern and Pacific times) on both Fox
Fox Broadcasting Company
Fox Broadcasting Company, commonly referred to as Fox Network or simply Fox , is an American commercial broadcasting television network owned by Fox Entertainment Group, part of Rupert Murdoch's News Corporation. Launched on October 9, 1986, Fox was the highest-rated broadcast network in the...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Global
Global Television Network
Global Television Network is an English language privately owned television network in Canada, owned by Calgary-based Shaw Communications, as part of its Shaw Media division...
in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. "Simulcast" is often a colloquial term for the related Canadian practice of simultaneous substitution
Simultaneous substitution
Simultaneous substitution is a practice mandated by the Canadian Radio-television and Telecommunications Commission requiring Canadian cable, direct broadcast satellite and multichannel multipoint distribution service television distribution companies to substitute the signal of a foreign or...
(simsub).
In sports, simulcasts are when a single announcer broadcasts play-by-play coverage both over television and radio. The practice was common in the early years of television, but since the 1980s, most teams have used a separate team for television and for radio.
As all NFL
National Football League
The National Football League is the highest level of professional American football in the United States, and is considered the top professional American football league in the world. It was formed by eleven teams in 1920 as the American Professional Football Association, with the league changing...
television broadcasts are done by the national networks or via cable, there are no regular TV-to-radio football simulcasts. However, NFL rules require that games airing on cable and satellite networks (ESPN
ESPN
Entertainment and Sports Programming Network, commonly known as ESPN, is an American global cable television network focusing on sports-related programming including live and pre-taped event telecasts, sports talk shows, and other original programming....
, NFL Network
NFL Network
NFL Network is an American television specialty channel owned and operated by the National Football League . It was launched November 4, 2003, only eight months after the league's 32 team owners voted unanimously to approve its formation...
) are simulcast on local over-air TV stations in markets serving the two local teams participating in each game.
Similarly, no current National Basketball Association
National Basketball Association
The National Basketball Association is the pre-eminent men's professional basketball league in North America. It consists of thirty franchised member clubs, of which twenty-nine are located in the United States and one in Canada...
teams use a simulcast. Al McCoy
Al McCoy (announcer)
Al McCoy , sometimes nicknamed as The Voice Of The Suns, has been the radio broadcast announcer of Phoenix Suns NBA basketball games since 1972 which makes him the longest tenured broadcaster in the NBA...
(Phoenix
Phoenix Suns
The Phoenix Suns are a professional basketball team based in Phoenix, Arizona. They are members of the Pacific Division of the Western Conference in the National Basketball Association and the only team in their division not to be based in California. Their home arena since 1992 has been the US...
), Chick Hearn
Chick Hearn
Francis Dayle "Chick" Hearn was an American sportscaster. Known primarily as the long-time play-by-play announcer for the Los Angeles Lakers of the National Basketball Association, the legendary Hearn is remembered for his rapid fire, staccato broadcasting style, inventing colorful phrases such...
(Los Angeles Lakers
Los Angeles Lakers
The Los Angeles Lakers are an American professional basketball team based in Los Angeles, California. They play in the Pacific Division of the Western Conference in the National Basketball Association...
), Kevin Calabro
Kevin Calabro
Kevin Calabro is an American play-by-play announcer and talk show host for 710 ESPN Seattle. The Kevin Calabro Show airs from 3-6p PT and features cohost and Seattle P-I columnist Jim Moore, as well as ESPN Senior NFL Writer and Analyst John Clayton...
(Seattle
Seattle SuperSonics
The Seattle SuperSonics were an American professional basketball team based in Seattle, Washington that played in the Pacific and Northwest Divisions of the National Basketball Association from 1967 until 2008. Following the 2007–08 season, the team relocated to Oklahoma City, and now plays as...
) and Rod Hundley
Rod Hundley
Rodney Clark "Rod" Hundley is a former professional basketball player and television broadcaster. Hundley's life has revolved around the game of basketball. His love and talent for the game led him to achieve honors in high school and most notably during his college years...
(Utah
Utah Jazz
The Utah Jazz is a professional basketball team based in Salt Lake City, Utah. They are currently a part of the Northwest Division of the Western Conference in the National Basketball Association...
) were the last NBA team broadcasters to simulcast.
In Major League Baseball
Major League Baseball
Major League Baseball is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League...
, only Vin Scully
Vin Scully
Vincent Edward Scully is an American sportscaster, known primarily as the play-by-play voice of the Brooklyn and Los Angeles Dodgers baseball team on Prime Ticket, KCAL-TV and KABC radio...
continues the practice; however, he simulcasts only the first three innings of Los Angeles Dodgers
Los Angeles Dodgers
The Los Angeles Dodgers are a professional baseball team based in Los Angeles, California. The Dodgers are members of Major League Baseball's National League West Division. Established in 1883, the team originated in Brooklyn, New York, where it was known by a number of nicknames before becoming...
games at Dodger Stadium
Dodger Stadium
Dodger Stadium, also sometimes called Chavez Ravine, is a stadium in Los Angeles. Located adjacent to Downtown Los Angeles, Dodger Stadium has been the home ballpark of Major League Baseball's Los Angeles Dodgers team since 1962...
and other National League
National League
The National League of Professional Baseball Clubs, known simply as the National League , is the older of two leagues constituting Major League Baseball, and the world's oldest extant professional team sports league. Founded on February 2, 1876, to replace the National Association of Professional...
Western Division parks.
The practice is most prevalent in the National Hockey League
National Hockey League
The National Hockey League is an unincorporated not-for-profit association which operates a major professional ice hockey league of 30 franchised member clubs, of which 7 are currently located in Canada and 23 in the United States...
where three teams simulcast:
- BuffaloBuffalo SabresThe Buffalo Sabres are a professional ice hockey team based in Buffalo, New York. They are members of the Northeast Division of the Eastern Conference of the National Hockey League .-Founding and early success: 1970-71—1980-81:...
, with Rick JeanneretRick JeanneretRichard "Rick" Jeanneret is the television and radio play-by-play announcer for the National Hockey League's Buffalo Sabres and its broadcast network, the Sabres Hockey Network. Having started with the team on radio during the 1971–72 season, he is the longest-tenured announcer in the NHL...
and Harry NealeHarry NealeHarold Watson Neale is a hockey colour commentator, who currently works for the Buffalo Sabres on the Sabres Hockey Network...
(and, on Saturdays, Mike RobitailleMike RobitailleMichael James David Robitaille is a retired Canadian professional ice hockey defenceman. He played in the National Hockey League with the New York Rangers, Detroit Red Wings, Buffalo Sabres and Vancouver Canucks...
), - DallasDallas StarsThe Dallas Stars are a professional ice hockey team based in Dallas, Texas. They are members of the Pacific Division of the Western Conference of the National Hockey League . The team was founded during the 1967 NHL expansion as the Minnesota North Stars, based in Bloomington, Minnesota. The...
, with Ralph StrangisRalph StrangisRalph Strangis is a play-by-play commentator, who has covered a variety of sports, but most notably has been the commentator for the Dallas Stars ice hockey franchise of the National Hockey League since the team's move to Dallas in 1993....
and Daryl ReaughDaryl ReaughDaryl "Razor" Reaugh , is a retired professional ice hockey goaltender, now a color commentator for the Dallas Stars of the NHL, the The NHL on Versus and Hockey Night in Canada.-Playing career:...
(popularly known as "Ralph and Razor"), and - New York IslandersNew York IslandersThe New York Islanders are a professional ice hockey team based in Uniondale, New York. They are members of the Atlantic Division of the Eastern Conference of the National Hockey League...
, with Howie RoseHowie RoseHowie Rose is an American sportscaster. He is currently the radio voice of the New York Mets on WFAN, and the television announcer for the New York Islanders on MSG Plus.-Early life and career:...
and Billy JaffeBilly JaffeBilly Jaffe is the former color analyst for the New York Islanders on MSG Plus. He is a color analyst and reporter for nationally televised hockey games on Versus.-Playing career:...
.
Simulcasts via satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
can be a challenge, as there is a significant delay
Delay (audio effect)
Delay is an audio effect which records an input signal to an audio storage medium, and then plays it back after a period of time. The delayed signal may either be played back multiple times, or played back into the recording again, to create the sound of a repeating, decaying echo.-Early delay...
because of the distance
Distance
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria . In mathematics, a distance function or metric is a generalization of the concept of physical distance...
- nearly 50000 miles (80,467 km) round-trip - involved. Anything involving video compression (and to some extent audio data compression) also has an additional significant delay, which is noticeable when watching local TV stations on direct broadcast satellite
Direct broadcast satellite
Direct broadcast satellite is a term used to refer to satellite television broadcasts intended for home reception.A designation broader than DBS would be direct-to-home signals, or DTH. This has initially distinguished the transmissions directly intended for home viewers from cable television...
s. Even though the process is not instantaneous, this is still considered a simulcast because it is not intentionally stored anywhere.
(Multiplexing
Multiplexing
The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...
-- also sometimes called "multicasting" -- is something of a reversal of this situation, where multiple program streams are combined into a single broadcast. The two terms are sometimes confused.)
In horse racing, a simulcast is a broadcast of a horse race which allows wagering
Gambling
Gambling is the wagering of money or something of material value on an event with an uncertain outcome with the primary intent of winning additional money and/or material goods...
at two or more sites; the simulcast often involves the transmission of wagering information to a central site, so that all bettors may bet in the same betting pool, as well as the broadcast of the race.
The San Francisco Giants
San Francisco Giants
The San Francisco Giants are a Major League Baseball team based in San Francisco, California, playing in the National League West Division....
simulcast with the Oakland Athletics
Oakland Athletics
The Oakland Athletics are a Major League Baseball team based in Oakland, California. The Athletics are a member of the Western Division of Major League Baseball's American League. From to the present, the Athletics have played in the O.co Coliseum....
while playing each other on their respective stations and commercials with a mix of broadcasters from both teams.
On cable television
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
systems, analog-digital simulcasting (ADS) means that analog channels are duplicated as digital subchannel
Digital subchannel
In broadcasting, digital subchannels are a means to transmit more than one independent program at the same time from the same digital radio or digital television station on the same radio frequency channel. This is done by using data compression techniques to reduce the size of each individual...
s. Digital tuners are programmed to use the digital subchannel instead of the analog. This allows for smaller, cheaper cable boxes by eliminating the analog tuner and some analog circuitry. On DVR
Digital video recorder
A digital video recorder , sometimes referred to by the merchandising term personal video recorder , is a consumer electronics device or application software that records video in a digital format to a disk drive, USB flash drive, SD memory card or other local or networked mass storage device...
s, it eliminates the need for an MPEG encoder to convert the analog signal to digital for recording. The primary advantage is the elimination of interference, and as analog channels are dropped, the ability to put 10 or more SDTV (or two HDTV, or various other combinations) channels in its place. The primary drawback is the common problem of over-compression (quantity over quality) resulting in fuzzy pictures and pixelation
Pixelation
In computer graphics, pixelation is an effect caused by displaying a bitmap or a section of a bitmap at such a large size that individual pixels, small single-colored square display elements that comprise the bitmap, are visible to the eye...
.
In universities with multiple campuses, simulcasting may be used for a single teacher to teach class to students in two or more locations at the same time, using videoconferencing
Videoconferencing
Videoconferencing is the conduct of a videoconference by a set of telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously...
equipment.
In many public safety agencies, simulcast refers to the broadcasting of the same transmission on the same frequency from multiple towers either simultaneously, or offset by a fixed number of microseconds. This allows for a larger coverage area without the need for a large number of channels, resulting in increased spectral efficiency
Spectral efficiency
Spectral efficiency, spectrum efficiency or bandwidth efficiency refers to the information rate that can be transmitted over a given bandwidth in a specific communication system...
. This comes at the cost of overall poorer voice quality, as multiple sources increase multipath interference
Multipath interference
Multipath interference is a phenomenon in the physics of waves whereby a wave from a source travels to a detector via two or more paths and, under the right condition, the two components of the wave interfere...
significantly, resulting in what is called simulcast distortion.
With some of the latest Simulcast control equipment for FM radio networks, the distortion experienced is almost in-audible to the human ear. With the introduction of Line Equalisation Modules and Tone Generation Modules, the phasing advance and retard is so well calculated that the distortion is almost entirely averted.
The Tone Generation Module (or TGM) generates a pilot tone at 3300 Hz which is then sampled by the Line Equalisation Module (or LEM) which each channel on each radio high site has 2 of located back at the main control site. This then determines the phase shift in the signal and adjusts the transmission accordingly such that all the overlap areas in transmission are in phase with each other.