Television receive-only is a term used chiefly in North America to refer to the reception of satellite television from FSS-type satellites on C-band analog. TVRO was the main means of consumer satellite reception in the United States and Canada until the mid-1990s with the arrival of direct-broadcast satellite television services such as PrimeStar, USSB, Bell TV, DirecTV, Dish Network, Sky TV that transmit Ku signals. While these services are at least theoretically based on open standards, the majority of services are encrypted and require proprietary decoder hardware. TVRO systems relied on feeds being transmitted unencrypted and using open standards, which contrasts to DBS systems in the region; the term is used to refer to receiving digital television "backhaul" feeds from FSS-type satellites. Reception of free-to-air satellite signals Ku band Digital Video Broadcasting, for home viewing is still common in Europe and Australia, although the TVRO nomenclature was never used there. Free-to-air satellite signals are very common in the People's Republic of China, as many rural locations cannot receive cable television and rely on satellites to deliver television signals to individual homes.
The term "BUD" is a colloquialism for C-Band satellite dishes used by TVRO systems. BUDs range from 4 to 16 feet with the most popular large size being 10 feet; the name comes from their perception as an eyesore. TVRO systems were marketed in the late 1970s. On October 18, 1979, the FCC began allowing people to have home satellite earth stations without a federal government license; the dishes were nearly 20 feet in diameter, were remote controlled, could only pick up HBO signals from one of two satellites. The receivers were 12 to 16 feet in diameter and made of solid fiberglass with an embedded metal coating, with models being 4 to 10 feet and made of wire mesh and solid steel or aluminum. Early dishes cost more than $5,000, sometimes as much as $10,000; the wider that the dish was, the better its ability to provide adequate channel reception. Programming sent from ground stations was relayed from 18 satellites in geostationary orbit located 22,300 miles above the Earth; the dish had to be pointed directly with nothing blocking the signal.
Weaker signals required larger dishes. The dishes worked by receiving a low-power C-Band frequency-modulated analog signal directly from the original distribution satellite – the same signal received by cable television headends; because analog channels took up an entire transponder on the satellite, each satellite had a fixed number of transponders, dishes were equipped with a modified polar mount and actuator to sweep the dish across the horizon to receive channels from multiple satellites. Switching between horizontal and vertical polarization was accomplished by a small electric servo motor that moved a probe inside the feedhorn throat at the command of the receiver. Higher-end receivers did this transparently, switching polarization and moving the dish automatically as the user changed channels. By Spring of 1984, 18 C-Band satellites were in use for United States domestic communications, owned by five different companies; the retail price for satellite receivers soon dropped, with some dishes costing as little as $2,000 by mid-1984.
Dishes pointing to one satellite were cheaper. Once a user paid for a dish, it was possible to receive premium movie channels, raw feeds of news broadcasts or television stations from other areas. People in areas without local broadcast stations, people in areas without cable television, could obtain good-quality reception with no monthly fees. By the end of 1984, an estimated one million dishes were in use, with over 120 channels available, some not available any other way; some people who installed dishes were not happy with cable. HBO and other cable-originated services were considering scrambling so that people would have to pay to receive them in the same manner as cable television systems. All channels could be received in the clear and free of charge. In October 1984, the U. S. Congress passed the Cable Communications Act of 1984, which gave those using dishes the right to see signals for free unless they were scrambled, required those who did scramble to make their signals available for a fee.
Since cable channels could prevent reception by big dishes, other companies had an incentive to offer competition. In 1986, HBO began using the now-obsolete VideoCipher system to encrypt their channels; this met with much protest from owners of big-dish systems, most of which had no other option at the time for receiving such channels. HBO allowed dish owners to subscribe directly to their service, although at a price much higher than what cable subscribers were paying; this led to the 1986 attack on HBO's transponder on Galaxy 1. One by one, all commercial channels began encrypting their channels. Analogue encryption using VideoCipher and VideoCipher II could be defeated, there was a black market for illegal descramblers. In the mid-1990s, some channels began moving their broadcasts to digital television transmission using the DigiCipher conditional access system. By 1987, nine channels were scrambled. While HBO charged a monthly fee of $19.95, soon it became possible to unscramble all channels for $200 a year.
Dish sales went down from 600,000 in 1985 to 350,000 in 1986, but pay television services were seeing dishes as something positive since some people would never have cable service, the industry was start
Analog television or analogue television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness and sound are represented by rapid variations of either the amplitude, frequency or phase of the signal. Analog signals vary over a continuous range of possible values which means that electronic noise and interference becomes reproduced by the receiver, thus with analog, a moderately weak signal becomes subject to interference. In contrast, a moderately weak digital signal and a strong digital signal transmit equal picture quality. Analog television can be distributed over a cable network using cable converters. All broadcast. Motivated by the lower bandwidth requirements of compressed digital signals, since the 2000s a digital television transition is proceeding in most countries of the world, with different deadlines for cessation of analog broadcasts; the earliest systems of analog television were mechanical television systems, which used spinning disks with patterns of holes punched into the disc to scan an image.
A similar disk reconstructed the image at the receiver. Synchronization of the receiver disc rotation was handled through sync pulses broadcast with the image information; however these mechanical systems were slow, the images were dim and flickered and the image resolution low. Camera systems used similar spinning discs and required intensely bright illumination of the subject for the light detector to work. Analog television did not begin as an industry until the development of the cathode-ray tube, which uses a focused electron beam to trace lines across a phosphor coated surface; the electron beam could be swept across the screen much faster than any mechanical disc system, allowing for more spaced scan lines and much higher image resolution. Far less maintenance was required of an all-electronic system compared to a spinning disc system. All-electronic systems became popular with households after the Second World War. Broadcasters of analog television encode their signal using different systems.
The official systems of transmission are named: A, B, C, D, E, F, G, H, I, K, K1, L, M and N. These systems determine the number of scan lines, frame rate, channel width, video bandwidth, video-audio separation, so on; the colors in those systems are encoded with one of three color coding schemes: NTSC, PAL, or SECAM, use RF modulation to modulate this signal onto a high frequency or ultra high frequency carrier. Each frame of a television image is composed of lines drawn on the screen; the lines are of varying brightness. The next sequential frame is displayed; the analog television signal contains timing and synchronization information, so that the receiver can reconstruct a two-dimensional moving image from a one-dimensional time-varying signal. The first commercial television systems were black-and-white. A practical television system needs to take luminance, chrominance and audio signals, broadcast them over a radio transmission; the transmission system must include a means of television channel selection.
Analog broadcast television systems come in a variety of frame resolutions. Further differences exist in the modulation of the audio carrier; the monochrome combinations still existing in the 1950s are standardized by the International Telecommunication Union as capital letters A through N. When color television was introduced, the hue and saturation information was added to the monochrome signals in a way that black and white televisions ignore. In this way backwards compatibility was achieved; that concept is true for all analog television standards. There were three standards for the way the additional color information can be encoded and transmitted; the first was the American NTSC color television system. The European/Australian PAL and the French-former Soviet Union SECAM standard were developed and attempt to cure certain defects of the NTSC system. PAL's color encoding is similar to the NTSC systems. SECAM, uses a different modulation approach than PAL or NTSC. In principle, all three color encoding systems can be combined with any scan line/frame rate combination.
Therefore, in order to describe a given signal it's necessary to quote the color system and the broadcast standard as a capital letter. For example, the United States, Canada and South Korea use NTSC-M, Japan uses NTSC-J, the UK uses PAL-I, France uses SECAM-L, much of Western Europe and Australia use PAL-B/G, most of Eastern Europe uses SECAM-D/K or PAL-D/K and so on. However, not all of these possible combinations exist. NTSC is only used with system M though there were experiments with NTSC-A in the UK and NTSC-N in part of South America. PAL is used with a variety of 625-line standards but with the North American 525-line standard, accordingly n
Video is an electronic medium for the recording, playback and display of moving visual media. Video was first developed for mechanical television systems, which were replaced by cathode ray tube systems which were replaced by flat panel displays of several types. Video systems vary in display resolution, aspect ratio, refresh rate, color capabilities and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, network streaming. Video technology was first developed for mechanical television systems, which were replaced by cathode ray tube television systems, but several new technologies for video display devices have since been invented. Video was exclusively a live technology. Charles Ginsburg led an Ampex research team developing one of the first practical video tape recorder. In 1951 the first video tape recorder captured live images from television cameras by converting the camera's electrical impulses and saving the information onto magnetic video tape.
Video recorders were sold for US $50,000 in 1956, videotapes cost US $300 per one-hour reel. However, prices dropped over the years; the use of digital techniques in video created digital video, which allows higher quality and much lower cost than earlier analog technology. After the invention of the DVD in 1997 and Blu-ray Disc in 2006, sales of videotape and recording equipment plummeted. Advances in computer technology allows inexpensive personal computers and smartphones to capture, store and transmit digital video, further reducing the cost of video production, allowing program-makers and broadcasters to move to tapeless production; the advent of digital broadcasting and the subsequent digital television transition is in the process of relegating analog video to the status of a legacy technology in most parts of the world. As of 2015, with the increasing use of high-resolution video cameras with improved dynamic range and color gamuts, high-dynamic-range digital intermediate data formats with improved color depth, modern digital video technology is converging with digital film technology.
Frame rate, the number of still pictures per unit of time of video, ranges from six or eight frames per second for old mechanical cameras to 120 or more frames per second for new professional cameras. PAL standards and SECAM specify 25 frame/s. Film is shot at the slower frame rate of 24 frames per second, which complicates the process of transferring a cinematic motion picture to video; the minimum frame rate to achieve a comfortable illusion of a moving image is about sixteen frames per second. Video can be progressive. In progressive scan systems, each refresh period updates all scan lines in each frame in sequence; when displaying a natively progressive broadcast or recorded signal, the result is optimum spatial resolution of both the stationary and moving parts of the image. Interlacing was invented as a way to reduce flicker in early mechanical and CRT video displays without increasing the number of complete frames per second. Interlacing retains detail while requiring lower bandwidth compared to progressive scanning.
In interlaced video, the horizontal scan lines of each complete frame are treated as if numbered consecutively, captured as two fields: an odd field consisting of the odd-numbered lines and an field consisting of the even-numbered lines. Analog display devices reproduce each frame doubling the frame rate as far as perceptible overall flicker is concerned; when the image capture device acquires the fields one at a time, rather than dividing up a complete frame after it is captured, the frame rate for motion is doubled as well, resulting in smoother, more lifelike reproduction of moving parts of the image when viewed on an interlaced CRT display. NTSC, PAL and SECAM are interlaced formats. Abbreviated video resolution specifications include an i to indicate interlacing. For example, PAL video format is described as 576i50, where 576 indicates the total number of horizontal scan lines, i indicates interlacing, 50 indicates 50 fields per second; when displaying a natively interlaced signal on a progressive scan device, overall spatial resolution is degraded by simple line doubling—artifacts such as flickering or "comb" effects in moving parts of the image which appear unless special signal processing eliminates them.
A procedure known as deinterlacing can optimize the display of an interlaced video signal from an analog, DVD or satellite source on a progressive scan device such as an LCD television, digital video projector or plasma panel. Deinterlacing cannot, produce video quality, equivalent to true progressive scan source material. Aspect ratio describes the proportional relationship between the width and height of video screens and video picture elements. All popular video formats are rectangular, so can be described by a ratio between width and height; the ratio width to height for a traditional television screen is 4:3, or about 1.33:1. High definition televisions use an aspect ratio of 16:9, or about 1.78:1. The aspect ratio of a full 35 mm film frame with soundtrack is 1.375:1. Pixels on computer monitors are square, but pixels used in digital video have non-square aspect ratios, such as those used in the PAL and NTSC variants of the CCIR 601 digital video
CCIR System B
CCIR System B was the 625-line analog broadcast television system which at its peak was the system used in most countries. It is being replaced across part of Asia and Africa by digital broadcasting; the system was developed for VHF band. A frame is the total picture; the frame rate is the number of pictures displayed in one second. But each frame is scanned twice interleaving odd and lines; each scan is known as a field So field rate is twice the frame rate. In each frame there are 625 lines So line rate 625 • 25 = 15625 Hz; the video bandwidth is 5.0 MHz. The video signal modulates the carrier by Amplitude Modulation, but a portion of the lower side band is suppressed. This technique is known as vestigial side band modulation; the polarity of modulation is negative, meaning that an increase in the instantaneous brightness of the video signal results in a decrease in RF power and vice versa. The sync pulses result in maximum power from the transmitter; the primary audio signal is modulated by Frequency modulation with a preemphasis time constant of τ = 50 μs.
The deviation for a 1.0 kHz. AF signal is 50 kHz; the separation between the primary audio FM subcarrier and the video carrier is 5.5 MHz. The total RF bandwidth of System B was 6.5 MHz, allowing System B to be transmitted in the 7.0 MHz wide channels specified for television in the VHF bands with an ample 500 kHz guard zone between channels. In specs, other parameters such as vestigial sideband characteristics and gamma of display device are given. System B has variously been used with both the SECAM colour systems, it could have been used with a 625-line variant of the NTSC color system, but apart from possible technical tests in the 1950s, this has never been done officially. When used with PAL, the colour subcarrier is 4.43361875 MHz and the sidebands of the PAL signal have to be truncated on the high-frequency side at +570 kHz. On the low-frequency side, the full 1.3 MHz sideband is radiated. When used with SECAM, the'R' lines' carrier is at 4.40625 MHz deviating from +350±18 kHz to -506±25 kHz.
The'B' lines' carrier is at 4.250 MHz deviating +506±25 kHz to -350±18 kHz. Neither colour encoding system has any effect on the bandwidth of system B as a whole. Enhancements have been made to the specification of System B's audio capabilities over the years; the introduction of Zweiton in the 1970s allowed for stereo sound or twin monophonic audio tracks. This was implemented by adding a second FM audio subcarrier at +5.74 MHz. Alternatively, starting in the late 1980s and early 1990s it became possible to replace the second audio FM subcarrier with a digital signal carrying NICAM sound. Either of these extensions to audio capability have eaten into the guard band between channels. Zweiton uses an extra 150 kHz; the alternative NICAM system uses an extra 500 kHz, needs to be spaced further from the primary audio subcarrier, thus System B with NICAM has only 150 kHz guard zones between channels. System B was the first internationally accepted 625-line broadcasting standard in the world; the European 41-68 MHz Band I television allocation was agreed at the 1947 ITU conference in 1947, the first European channel plan was agreed in 1952 at the ITU conference in Stockholm.
The extension to VHF Band III was agreed in the 1950s. Since the System B specification has been used with different broadcast frequencies in many other countries. † Channel 1 was never used. § Not used in the former East Germany Transmitters were operational on the above channels in 1959. During the 1960s, channels 1 to 3 were deleted and channels E3 to E12 adopted, bringing East Germany into line with the channel allocations used in the West. Italian channel-spacings were erratic. System B is no longer in use in Italy, the switchover to DVB-T having been completed 4 July 2012. Note: Band I is no longer used for television in Italy. Note: Unusually for Europe, Band III is used for DVB-T in Italy. At digital switchover time, Italy took the opportunity to discontinue their erratic System B frequencies, the digital channels are regularly-spaced every 7.0 MHz from 177.5 MHz. Australia were unique in the world by their use of Band II for television broadcasting. ‡ Channels 3, 4 and 5 were scheduled to be cleared during 1993-96 to make way for FM radio stations in Band II.
This clearance action took much longer than was anticipated, as a result, many stations on channel 3 still remain, along with a few on 4 and 5. ♦ New channel allocations from 1993. ‡ Channels 10 and 11 were shifted up in frequency by 1 MHz to make room for channel 9A. The frequencies of existing stations did not change. Digital multiplexes on channels 10 and 11 are using the new channel boundaries. Australia are nearly unique in the world for their use of 7 MHz channel-spacing on UHF. † Added in the 1980s ‡ Added in the 1990s Note: the Band III frequencies are the same as Australia's. When the UHF bands came into use in the early 1960s, two variants of System B began to be used on those frequencies. In most countries, the channels on the UHF bands are
CCIR System G
CCIR System G is an analog broadcast television system used in many countries. There are several systems in use and letter G is assigned for the European UHF system, used in the majority of Asian and African countries; some of the important specs are listed below. A frame is the total picture; the frame rate is the number of pictures displayed in one second. But each frame is scanned twice interleaving odd and lines; each scan is known as a field So field rate is twice the frame rate. In each frame there are 625 lines So line rate 625 • 25 = 15625 Hz; the RF parameters of the transmitted signal are the same as those for System B, used on the 7.0 MHz wide channels of the VHF bands. The only difference is the width of the guard band between the channels, which on System G is 1.0 MHz wider than for System B: in other words 1.15 MHz. A few countries use a variant of system G, known as System H. System H is similar to system G but the lower side band is 500 kHz wider; this makes much better use of the 8.0 MHz channels of the UHF bands by reducing the width of the guard-band by 500 kHz to the still generous value of 650 kHz.
Broadcast television systems Television transmitter Transposer World Analogue Television Standards and Waveforms Fernsehnormen aller Staaten und Gebiete der Welt
CCIR System H
CCIR System H is an analog broadcast television system used in Belgium, the Balkans and Malta on the UHF bands. Some of the important specs are listed below. A frame is the total picture; the frame rate is the number of pictures displayed in one second. But each frame is scanned twice interleaving odd and lines; each scan is known as a field So field rate is twice the frame rate. In each frame there are 625 lines So line rate 625 • 25 = 15625 Hz; the RF parameters of the transmitted signal are the same as those for System B, used on the 7.0 MHz wide channels of the VHF bands. The only difference to the RF spectrum of the signal is that the vestigial sideband is 500 kHz wider at 1.25 MHz. Due to this and the extra width of the channel allocations at UHF, the width of the guard band between the channels is 650 kHz. Many countries use a variant of system H, known as System G. System G is similar to system H but the lower side band is 500 kHz narrower; this makes poor use of the 8.0 MHz channels of the UHF bands by increasing the width of the guard-band by 500 kHz to 1.15 MHz.
The advantage is that the RF spectrum of system G is the same as system B, simplifying the band-switching circuitry in VHF/UHF televisions. Broadcast television systems Television transmitter Transposer World Analogue Television Standards and Waveforms Fernsehnormen aller Staaten und Gebiete der Welt
British Satellite Broadcasting
British Satellite Broadcasting was a television company, headquartered in London, that provided direct broadcast satellite television services to the United Kingdom. The company was merged with Sky Television plc on 2 November 1990 to form British Sky Broadcasting, it started broadcasting on 25 March 1990. In 1977, the World Administrative Radio Conference assigned each country five high-powered channels for direct broadcast by satellite for domestic use. In 1982, after being awarded two of the channels, the BBC proposed its own satellite service, with two conditions: Use of a satellite built by United Satellite, a consortium of British Aerospace and Matra Marconi Space, with costs estimated at £24M per year. A supplementary charter was agreed in May 1983 which allowed the BBC to borrow up to £225M to cover the cost of the project as it was not allowed to call on public funds, nor use existing sources of revenue to fund the project. During Autumn 1983, the cost of Unisat was found to be underestimated and the new Home Secretary announced the three remaining channels would be given to the Independent Broadcasting Authority to allow the private sector to compete against the BBC in satellite broadcasting.
Within a few months, the BBC started talking with the IBA about a joint project to help cover the cost. Subsequently, government allowed the IBA to bring in private companies to help cover the costs: The BBC – 50% ITV franchises Granada and Anglia Television – 30% Virgin / Thorn-EMI / Granada TV Rental / Pearson Longman and Consolidated Satellite Broadcasting – 20%Within a year the consortium made it clear that the original launch date of 1986 would be pushed back to 1988, while asking the government to allow them to tender out the building of the new satellite system, to help reduce cost; the project failed in May 1985 when the consortium concluded that the cost of set-up was not justifiable. The BBC stated the costs were prohibitive, because the government insisted that the BBC should pay for the costs of constructing and launching a dedicated satellite; the IBA convinced the Home Secretary to revive the DBS project but under different conditions, by inviting private-sector companies to apply for a new television franchise via satellite, to provide a commercial service on three of the five DBS channels on 2 April 1986.
One of the conditions imposed on applicants by the IBA was that they use a new, untried transmission standard, D-MAC. This standard was part of the European Community's attempt to promote a high-definition television standard being developed by Philips and other European companies, HD-MAC; the technology was still at the laboratory stage and was incompatible with previous standards: HD-MAC transmissions could not be received by existing television sets which were based on PAL or SECAM standards. The condition to use a high-power satellite was dropped, no winner was precluded from buying a foreign satellite system; the IBA received five serious bids for the Direct Broadcast Satellite franchises. It received submissions from The Children's Channel and ITN to make sure their programmes were used on any successful bid. British Satellite Broadcasting: Consortium of Granada Television, Virgin Group, Anglia Television and Independent Television News. Direct Broadcasting by Satellite UK Limited: Consortium of Carlton Communications, London Weekend Television and Saatchi, Dixons and Robert Fleming merchant bank.
It planned a sport/news/business channel, entertainment channel, Super Channel. Direct Broadcasting Limited: Consortium of British and Commonwealth Shipping, Cambridge Electronic Industries, Electronics Rental Group, Rupert Murdoch's News International and Sears; the first channel was for families and children, the second channel for films and the third channel would have broadcast Sky Channel. National Broadcasting Service: Consortium led by James Lee, former head of Goldcrest Films and Robert Holmes à Court's Bell Group. Promised schedules for children and sport fans along with a news channel. SatUK Broadcasting: Created by Muir Sutherland and Jimmy Hartley, backed by Australian finanicier Alan Bond and Celtic Films. Proposed a free-to-air entertainment channel, a £5 per month film channel and a £2 per month family channel. British Satellite Broadcasting won the fifteen-year franchise on 11 December 1986 to operate the Direct Broadcast Satellite System, with a licence to operate three channels.
BSB forecast 400,000 homes would be equipped during its first year, but some doubts were cast whether this was possible. The Cable Authority welcomed the service, believing it would encourage more users with its dedicated movie channel. BSB's original satellite channels were: Screen: feature film channel, with a subscription price of £2.50 per week Zigzag: kids and lifestyle channel, shared with Screen during the daytime Galaxy: entertainment channel, from 6pm Now: live 24-hour news and current affairs service, powered by Independent Television News Around the time of the licence award, Amstrad withdrew its backing as they believed it was not possible to sell a satellite dish and receiver for £250. Australian businessman Alan Bond joined the consortium along with Reed International, Next plc and London Merchant Securities amongst others. BSB earmarked the bulk of the first round of financing for buying and launching two satellites and planned a second round close to the commencement of broadcasting operations.