Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human operator, they can run in a "live assist" mode when there are on-air personnel present at the master control, television studio or control room. The radio transmitter end of the airchain is handled by a separate automatic transmission system. In the USA, many broadcast licensing authorities required a licensed board operator to run every station at all times, meaning that every DJ had to pass an exam to obtain a license to be on-air, if their duties required them to ensure proper operation of the transmitter; this was the case on overnight and weekend shifts when there was no broadcast engineer present, all of the time for small stations with only a contract engineer on call. In the U. S. it was necessary to have an operator on duty at all times in case the Emergency Broadcast System was used, as this had to be triggered manually.
While there has not been a requirement to relay any other warnings, any mandatory messages from the U. S. president would have had to first be authenticated with a code word sealed in a pink envelope sent annually to stations by the Federal Communications Commission. The quality and reliability of electronic equipment improved, regulations were relaxed, no operator had to be present while a station was operating. In the U. S. this came about when the EAS replaced the EBS, starting the movement toward automation to assist, sometimes take the place of, the live disc jockeys and radio personalities. Early automation systems were electromechanical systems. Systems were "computerized" only to the point of maintaining a schedule, were limited to radio rather than TV. Music would be stored on reel-to-reel audio tape. Subaudible tones on the tape marked the end of each song; the computer would rotate among the tape players until the computer's internal clock matched that of a scheduled event. When a scheduled event would be encountered, the computer would finish the currently-playing song and execute the scheduled block of events.
These events were advertisements, but could include the station's top-of-hour station identification, news, or a bumper promoting the station or its other shows. At the end of the block, the rotation among tapes resumed. Advertisements and the top-of-hour station identification required by law were on "carts". Short for cartridges, these were endless tapes similar to 4-track tapes, were mechanically identical as well, were called Fidelipacs; the primary difference between carts and 4 track is two fold. The Cart had only two tracks and the 4-track had four; the Cart ran at 7 and 1/2 IPS whereas the 4-Track ran at 3 and 3/4 IPS. Carts had a slot for a pinch roller on a spindle, activated by solenoid upon pressing the start button on the cart machine; the capstan was spinning at full speed and this allowed for nearly instantaneous playback start without artifacts. Mechanical carousels would rotate the carts in and out of multiple tape players as dictated by the computer. Time announcements were provided by a pair of dedicated cart players, with the minutes stored on one and the odd minutes on the other.
This meant an announcement would always be ready to play if the minute was changing when the announcement was triggered. The system did require attention throughout the day to change reels as they ran out and reload carts, it became obsolete when a method was developed to automatically rewind and re-cue the reel tapes when they ran out, extending'walk-away' time indefinitely. Radio station WIRX may have been one of the world's first automated radio stations and designed by Brian Jeffrey Brown in 1963 when Brown was only 10 years old; the station broadcast in a classical format, called "More Good Music" and featured five-minute bottom-of-the-hour news feeds from the Mutual Broadcasting System. The heart of the automation was an 8 x 24 telephone stepping relay which controlled two reel-to-reel tape decks, one twelve inch Ampex machine providing the main program audio and a second RCA seven inch machine providing "fill" music; the tapes played by these machines were produced in the Midwest Family Broadcasting Madison, Wisconsin production facility by WSJM Chief Engineer Richard E. McLemore with sub-audible tones used to signal the end of a song.
The stepping relay was programmed by slide switches in the front of the two relay racks which housed the equipment. The news feeds were triggered by a microswitch, attached to a Western Union clock and tripped by the minute hand of the clock, and reset the stepping relay. 30-minute station identification was accomplished by a simulcast switch in the control booth for sister station WSJM, whereupon the disc jockey in the booth would announce "This is WSJM-AM and...... WSJM-FM, St. Joseph, Michigan." This only lasted about six months, a standard tape cartridge player was wired in to announce the station identification and triggered by the Western Union clock. A different technology appeared in 1980 with the analog recorders made by Solidyne, which used a computer-controlled tape positioning system. Four GMS 204 units were controlled from a 6809 microprocessor, with the program stored in a solid-state plug-in memory module; this system has a limited programming time of about eight hours. Satellite programming used audible dual-tone multi-frequency signals to trigger
Cable television is a system of delivering television programming to consumers via radio frequency signals transmitted through coaxial cables, or in more recent systems, light pulses through fiber-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over the air by radio waves and received by a television antenna attached to the television. FM radio programming, high-speed Internet, telephone services, similar non-television services may be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation. A "cable channel" is a television network available via cable television; when available through satellite television, including direct broadcast satellite providers such as DirecTV, Dish Network and Sky, as well as via IPTV providers such as Verizon FIOS and AT&T U-verse is referred to as a "satellite channel". Alternative terms include "non-broadcast channel" or "programming service", the latter being used in legal contexts.
Examples of cable/satellite channels/cable networks available in many countries are HBO, Cinemax, MTV, Cartoon Network, AXN, E!, FX, Discovery Channel, Canal+, Fox Sports, Disney Channel, Nickelodeon, CNN International, ESPN. The abbreviation CATV is used for cable television, it stood for Community Access Television or Community Antenna Television, from cable television's origins in 1948. In areas where over-the-air TV reception was limited by distance from transmitters or mountainous terrain, large "community antennas" were constructed, cable was run from them to individual homes; the origins of cable broadcasting for radio are older as radio programming was distributed by cable in some European cities as far back as 1924. To receive cable television at a given location, cable distribution lines must be available on the local utility poles or underground utility lines. Coaxial cable brings the signal to the customer's building through a service drop, an overhead or underground cable. If the subscriber's building does not have a cable service drop, the cable company will install one.
The standard cable used in the U. S. is RG-6, which has a 75 ohm impedance, connects with a type F connector. The cable company's portion of the wiring ends at a distribution box on the building exterior, built-in cable wiring in the walls distributes the signal to jacks in different rooms to which televisions are connected. Multiple cables to different rooms are split off the incoming cable with a small device called a splitter. There are two standards for cable television. All cable companies in the United States have switched to or are in the course of switching to digital cable television since it was first introduced in the late 1990s. Most cable companies require a set-top box or a slot on one's TV set for conditional access module cards to view their cable channels on newer televisions with digital cable QAM tuners, because most digital cable channels are now encrypted, or "scrambled", to reduce cable service theft. A cable from the jack in the wall is attached to the input of the box, an output cable from the box is attached to the television the RF-IN or composite input on older TVs.
Since the set-top box only decodes the single channel, being watched, each television in the house requires a separate box. Some unencrypted channels traditional over-the-air broadcast networks, can be displayed without a receiver box; the cable company will provide set top boxes based on the level of service a customer purchases, from basic set top boxes with a standard definition picture connected through the standard coaxial connection on the TV, to high-definition wireless DVR receivers connected via HDMI or component. Older analog television sets are "cable ready" and can receive the old analog cable without a set-top box. To receive digital cable channels on an analog television set unencrypted ones, requires a different type of box, a digital television adapter supplied by the cable company. A new distribution method that takes advantage of the low cost high quality DVB distribution to residential areas, uses TV gateways to convert the DVB-C, DVB-C2 stream to IP for distribution of TV over IP network in the home.
In the most common system, multiple television channels are distributed to subscriber residences through a coaxial cable, which comes from a trunkline supported on utility poles originating at the cable company's local distribution facility, called the "headend". Many channels can be transmitted through one coaxial cable by a technique called frequency division multiplexing. At the headend, each television channel is translated to a different frequency. By giving each channel a different frequency "slot" on the cable, the separate television signals do not interfere with each other. At an outdoor cable box on the subscriber's residence the company's service drop cable is connected to cables distributing the signal to different rooms in the building. At each television, the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency, it is displayed onscreen. Due to widespread cable theft in earlier analog systems, the signals are encrypted on m
Digital on-screen graphic
A digital on-screen graphic is a watermark-like station logo that most television broadcasters overlay over a portion of the screen area of their programs to identify the channel. They are thus a form of permanent visual station identification, increasing brand recognition and asserting ownership of the video signal. In some cases, the graphic shows the name of the current program; some television networks use an on-screen graphic to advertise upcoming programs. The graphic identifies the source of programming if it has been time-shifted—that is, recorded to videotape, DVD, or a digital personal video recorder such as TiVo. Many of these technologies allow viewers to skip or omit traditional between-programming station identification. DOG watermarking helps reducing off-the-air copyright infringement – for example, the distribution of a current series' episodes on DVD: the watermarked content is differentiated from "official" DVD releases, can help identify not only the station from which the broadcast was captured, but the actual date of the broadcast as well.
Graphics may be used to identify. For example, showing Sky Sports within a pub requires a more expensive subscription; the graphic changes at certain times, making it harder to counterfeit. On the other hand, watermarks pollute the picture, distract viewers' attention, may cover an important piece of information presented in the television program. Bright watermarks may cause screen burn-in on some types of TV sets. Usage of visually perceptible embedded watermarks requires program author to have a separate clean copy for archival purposes, but this practice was not common decades ago when watermarking became popular among broadcasters. Watermarks present an issue when archival videos are used for a documentary that strives to create a coherent story. In some cases watermarks are digitally removed if possible to clean up the picture. In the absence of visually perceptible watermarks content control can be ensured with visually imperceptible digital watermarks. Many news broadcasters, as well as a few television networks in such cases place a clock alongside their bug.
In the United States, Canada and New Zealand, DOGs may include the show's parental guideline rating. In Australia, this is known as a Program Return Graphic, it has become common to place text above the station's logo advertising other programs on the network. In many countries, some TV networks put "live" in the bottom of the DOG to advise viewers that the program is live, as opposed to a repeat. During televised sports events, a DOG may display a few game-related statistics such as the current score; this has led many people in the United States to refer to it as a score bug. Arabic TV logos are placed in the top-right and top-left except for Al-Jazeera, whose logo appears on the bottom-right of the screen; some of the Arabian TV stations hide their logos during commercial breaks and promos/trailers, such as Dubai TV, Dubai One, the Egyptian CBC and Nile TV networks, ART Hekayat, ART Hekayat 2, Iqraa and Al-Jazeera. Abu Dhabi TV and MBC 1 had their logos at the bottom-right corner from their launch until the mid-2000s, when they were moved to the top-right corner.
Beginning in the late 1990s all television stations in Argentina had their logos being shown on the top-right of the screen. When Canal 9 relaunched in 2002 to replace Azul Televisión, its logo was shown on the bottom-left of the screen. After intense criticism, Canal 9 moved its logo to the top-right of the screen of which most Argentine broadcasters had always followed. Australia first introduced the digital on-screen graphic in the early 1990s; the Seven Network was the first metropolitan network to broadcast digital on-screen graphics on all of their programs, following The Nine Network in mid-to-late 2002 Network Ten in 2004. DOGs in Australia most appear in the bottom-right hand corner of the screen, but sports orientated content that uses the network's sports brand appear on the top-right hand corner of the screen. One placed its DOG in the top-right hand corner of the screen due to it being a sports orientated channel at the time, but after the 2011 rebrand to allow a wide range of content to be broadcast, the channel's DOG was moved to the bottom-right hand corner of the screen.
The ABC3 and ABC Kids channels placed their DOGs in the top-left hand corner of the screen, but have since moved them down to the bottom-right hand corner as of late 2013. Datacasting channels and home shopping channels show their DOGs in the top-right hand corner of the screen. DOGs are shown in a semi-transparent format, but are shown opaque during in-programme advertisements that take place at the bottom of the screen. News services have their own DOGs placed where their network's DOG would be, but are only shown in an opaque format. News services show footage, captured by another network, but the semi-transparent DOG of the original network is still shown. Current affairs programmes and other news programmes that are produced by the networ
A vision mixer is a device used to select between several different video sources and, in some cases, compositing video sources together to create special effects. This is similar to. A vision mixer would be found in a video production environment such as a television studio, production truck, OB Van or linear video editing bay of a post-production facility. In most of the world, both the equipment and its operator are called a vision video mixer. Besides hard cuts, mixers can generate a variety of transitions, from simple dissolves to pattern wipes. Additionally, most vision mixers can generate color signals. Most vision mixers are targeted at the professional market, with newer analog models having component video connections and digital ones using Serial Digital Interface, they are used in live television, such as outside broadcasts, with video tape recording and video servers for linear video editing though the use of vision mixers in video editing has been supplanted by computer based Non-linear editing systems.
Older professional mixers worked with analog signal inputs. There are still a number of consumer video switchers with composite video, S-Video or FireWire available; these are used for VJing and small multi-camera productions. The most basic part of a vision mixer is a bus, a signal path consisting of multiple video inputs that feeds a single output. On the panel, a bus is represented by a row of buttons. Older video mixers had two equivalent buses, one of these buses could be selected as the main out bus. Most modern mixers, have one bus, always the program bus, the second main bus being the preview bus; these mixers are called flip-flop mixers, since the selected source of the preview and program buses can be exchanged. Some switchers allow the operator to switch between these two modes. Both the preview and program bus have their own video monitors displaying the video selected in their respective buses. Another main feature of a vision mixer is the transition lever called a T-bar or Fader Bar.
This lever, similar to an audio fader, is used to transition between two buses. Note that in a flip-flop mixer, the position of the main transition lever does not indicate which bus is active, since the program bus is always the active or hot bus. Instead of moving the lever by hand, a button can be used, which performs the transition over a user-defined period of time. Another button labeled "cut" or "take", swaps the preview signal to the program signal instantaneously; the type of transition used can be selected in the transition section. Common transitions include dissolves and pattern wipes. A third bus used for compositing is the key bus. A mixer can have more than one key bus, but they share only one set of buttons. Here, one signal can be selected for keying over the program bus; the digital on-screen graphic image that will be seen in the program is called the fill, while the mask used to cut the key's translucence is called the source. This source, e.g. chrominance, pattern or split and can be selected in the keying section of the mixer.
Note that instead of the key bus, other video sources can be selected for the fill signal, but the key bus is the most convenient method for selecting a key fill. A key is turned on and off the same way a transition is. For this, the transition section can be switched from program mode to key mode; the transition section allows background video and one or more keyers to be transitioned separately or in any combination with one push of the "auto" button. These three main buses together form the basic mixer section called Program/Preset or P/P. Bigger production mixers may have a number of additional sections of this type, which are called Mix/Effects sections and numbered. Any M/E section can be selected as a source in the P/P stage, making the mixer operations much more versatile, since effects or keys can be composed "offline" in an M/E and go "live" at the push of one button. After the P/P section, there is another keying stage called the downstream keyer, it is used for keying text or graphics, has its own "Cut" and "Mix" buttons.
The signal before the DSK keyer is called clean feed. After the DSK is one last stage that overrides any signal with black called Fade To Black or FTB. Modern vision mixers may have additional functions, such as serial communications with the ability to use proprietary communications protocols, control auxiliary channels for routing video signals to other sources than the program out, macro programming, DVE capabilities. Mixers are equipped with effects memory registers, which can store a snapshot of any part of a complex mixer configuration and recall the setup with one button press. Since vision mixers combine various video signals such as VTRs and professional video cameras, it is important that all these sources are in proper synchronization with one another. In professional analog facilities all the equipment
A terrestrial network is a group of radio stations, television stations, or other electronic media outlets, that form an agreement to air, or broadcast, content from a centralized source. For example, PBS and BBC are TV networks that provide programming for local terrestrial television station affiliates to air using signals that can be picked up by the home television sets of local viewers. Large networks are national, but there is a Global Television Network. Streaming media, Internet radio, webcasting are sometimes considered forms of broadcasting despite the lack of terrestrial stations. Following the introduction of radio broadcasting in the early 1920s, the American Telephone and Telegraph Company developed the first radio network, linking together individual stations with specially prepared long-distance telephone lines in what at the time was called a "chain"; the key station was AT&T's WEAF in New York City. The network featured a variety of scheduled programs which included sponsorships.
From the beginning, AT&T planned to expand nationwide, so that national companies would be able reach large portions of the nation with their brand names and slogans in an efficient manner. At first the network's expansion was slow. In 1924, the Eveready Hour was broadcast over 12 stations located in the U. S. Northeast. Eveready Hour was the first commercially sponsored variety show in the history of broadcasting. By 1925, AT&T had linked together 26 stations in its network. AT&T decided to concentrate on its most profitable business, in 1926 sold its broadcasting interests to the Radio Corporation of America. RCA's purchase included an agreement to lease AT&T phone lines. In 1922 the Radio Corporation of America followed AT&T's network model lead, formed a small competing network centered on its New York City station, WJZ. However, conflict resulted as RCA had a limited ability to lease lines from AT&T, had to use telegraph lines to connect stations, which had inferior acoustical properties. After acquiring WEAF and AT&T's network assets in 1926, RCA created the National Broadcasting Company and reorganized the WEAF chain as the NBC Red network, the WJZ chain as the NBC Blue network.
On 23 December 1928, NBC instituted the first permanent transcontinental network. As of September 1938, when there were 154 NBC outlets. Supplementing these basic networks were 107 stations, of which one was available only to the basic Red network, six were available only to the basic Blue network, the remainder available to either. NBC had a chain of shortwave stations, called the "NBC White Network", in the 1930s. In 1941, the Federal Communication Commission's Report on Chain Broadcasting reviewed the alleged monopolistic practices of the radio networks; the FCC was concerned NBC NBC Blue were anti-competitive. Because the FCC did not have the power to directly regulate networks, it decided to enact regulations affecting the stations, adopted standards intended to force NBC to relinquish one of its networks. In 1943, the Supreme Court upheld the FCC's power to enforce its chain broadcasting regulations; as a consequence, NBC Blue was sold to Edward Noble who named it the American Broadcasting Company.
After NBC Blue was divested the remaining NBC Red network was renamed the NBC Radio Network. In 1927, United Independent Broadcasters, Inc. supported by the Columbia Phonograph Record Company, started a new network of 16 stations named the Columbia Phonographic Broadcasting System. In 1928 William S. Paley assumed control of the network, which under his leadership focused on entertainment programming and news affiliation, he turned the failing company around, named Columbia Broadcasting System, Inc. in 1929. By the end of 1938 there were 113 CBS outlets. Regional networks on CBS existed in various parts of the country. CBS hired Edward R. Murrow, credited with boosting ratings dramatically. Murrow and CBS covered the war in Europe. NBC and ABC withdrew from the war for safety reasons; as a result of taking the risk, CBS's ratings skyrocketed. In 1945, the NBC Blue network was sold to Edward John Noble, who renamed it American Broadcasting Company. By the mid-1940s broadcasting had become a big Three television networks battle.
ABC went bankrupt and in 1951 Leonard Goldenson and United Paramount Theaters bought the network for $25 million. In 1964, ABC won the ratings race in the fifty largest U. S. markets. In the 1970–71 season, ABC ranked #1 in the Nielsen ratings with a medical drama called Marcus Welby, M. D. the first ABC television show to top the list. In 1929, a group of four radio stations in the major markets of New York City, Chicago and Detroit organized into a loose confederation known as the Quality Network. In 1934 this was reorganized as the Mutual Broadcasting System