Who is the Inventor of Television?

You have really opened up a can of worms with that question! Probably no other invention in history has been as hotly disputed as the prestigious claim to the invention of 'Tele-vision or 'long-distance sight' by wireless.”

Since Marconi’s invention of wireless telegraphy in 1897, the imagination of many inventors have been sparked with the notion of sending images as well as sound, wirelessly. The first documented notion of sending components of pictures over a series of multiple circuits is credited to George Carey. Another inventor, W. E. Sawyer, suggested the possibility of sending an image over a single wire by rapidly scanning parts of the picture in succession.

On December 2, 1922, in Sorbonne, France, Edwin Belin, an Englishman, who held the patent for the transmission of photographs by wire as well as fiber optics and radar, demonstrated a mechanical scanning device that was an early precursor to modern television. Belin’s machine took flashes of light and directed them at a selenium element connected to an electronic device that produced sound waves. These sound waves could be received in another location and remodulated into flashes of light on a mirror.

Up until this point, the concept behind television was established, but it wasn’t until electronic scanning of imagery (the breaking up of images into tiny points of light for transmission over radio waves), was invented, that modern television received its start. But here is where the controversy really heats up.

The credit as to who was the inventor of modern television really comes down to two different people in two different places both working on the same problem at about the same time: Vladimir Kosma Zworykin, a Russian-born American inventor working for Westinghouse, and Philo Taylor Farnsworth, a privately backed farm boy from the state of Utah.

“Zworykin had a patent, but Farnsworth had a picture…”

Zworykin is usually credited as being the father of modern television. This was because the patent for the heart of the TV, the electron scanning tube, was first applied for by Zworykin in 1923, under the name of an iconoscope. The iconoscope was an electronic image scanner - essentially a primitive television camera. Farnsworth was the first of the two inventors to successfully demonstrate the transmission of television signals, which he did on September 7, 1927, using a scanning tube of his own design. Farnsworth received a patent for his electron scanning tube in 1930. Zworykin was not able to duplicate Farnsworth’s achievements until 1934 and his patent for a scanning tube was not issued until 1938. The truth of the matter is this, that while Zworykin applied for the patent for his iconoscope in 1923, the invention was not functional until some years later and all earlier efforts were of such poor quality that Westinghouse officials ordered him to work on something “more useful.”

Another player of the times was John Logie Baird, a Scottish engineer and entrepreneur who 'achieved his first transmissions of simple face shapes in 1924 using mechanical television. On March 25, 1925, Baird held his first public demonstration of 'television' at the London department store Selfridges on Oxford Street in London. In this demonstration, he had not yet obtained adequate half-tones in the moving pictures, and only silhouettes were visible.

In the late thirties, when RCA and Zworykin, who was now working for RCA, tried to claim rights to the essence of television, it became evident that Farnsworth held the priority patent in the technology. The president of RCA sought to control television the same way that they controlled radio and vowed that, “RCA earns royalties, it does not pay them,” and a 50 million dollar legal battle subsequently ensued.

In the height of the legal battle for patent priority, Farnsworth’s high school science teacher was subpoenaed and traveled to Washington to testify that as a 14 year old; Farnsworth had shared his ideas of his television scanning tube with his teacher.

With patent priority status ruled in favor of Farnsworth, RCA for the first time in its history began paying royalties for television in 1939.

Philo Farnsworth was recently named one of TIME Magazine's 100 Greatest Scientists and Thinkers of the 20th Century.~3589

 

 

Comments:

a precursor - вестник, предвестник

a n imagery - совокупность, ряд изображений, фото-, видео- и т. п. материалов, объединенных по какому-л. признаку; получение изображения

a controversy - дебаты, дискуссия, полемика, прения, спор

Westinghouse – компания, образованная Джорджем Вестингаузем

a n iconoscope - иконоскоп (передающая телевизионная трубка, предназначенная для преобразования оптического изображения в электрический сигнал)

RCA - Radio Corporation of America - американская радиокомпания, основанная в 1919 году.

to subpoena smb. to testify — вызывать кого-л. для дачи свидетельских показаний

 

 

Cable Television

Cable television is the transmission of televised images to viewers by means of coaxial cables. Cable systems receive the television signal, which is sent out over cables to individual subscribers, by a common antenna (CATV) or satellite dish. Early cable systems developed in the late 1940s to improve reception of commercial programming in rural areas. In the 1960s, cable systems expanded to large urban areas, where reception can also be poor, and the cable television industry began introducing its own networks, such as Home Box Office (HBO), founded in 1972, to provide programming exclusively to subscribers. Beginning in 1975, cable networks began distributing their shows to local cable operators via satellite, thus increasing the amount of programming available nationally. Heavily regulated in their early years, cable systems in many instances were required to provide channels for community access programming, and rate increases were controlled by local authorities. The financial problems caused by the high cost of wiring cities for cable led to legislation deregulating the industry in 1984. Cable operators were able to set their own rates until 1992, when complaints about the industry's monopoly power led to new legislation that gave the Federal Communications Commission the authority to limit rate increases.

During the 1980s and early 90s, the growing number of cable networks, improved programming, increased channel capacity (which reached 150 in some systems by 1992), and greater freedom in terms of programming content greatly expanded the industry. There are 10,828 operating cable systems in the United States serving 28,798 communities and 62 million subscribers; this comprises about 64% of all households. Viewers pay a monthly fee for a package of cable television programming, known as basic cable, and additional monthly fees for networks such as HBO, which are known as pay TV services. Cable television offers a wide variety of specialized programming, including channels devoted to specific interests, such as news, sports, movies, business information, weather, cooking, home shopping, and family viewing. It can also transmit programs from foreign cities, such as the proceedings of the British House of Commons. The industry finances its programming from subscriber fees and advertising revenue. New technologies, such as fibre optics, digital compression, and interactive television, allow cable operators to offer more programming choices and services. The cable lines installed by cable operators are also to use to provide broadband Internet access to the homes of subscribers.~2232

Comments:

coaxial - соосный, коаксиальный, имеющий общую ось

Home Box Office (HBO) — американский кабельный телевизионный канал, осуществляющий вещание по двум 24-часовым кабельным каналам: HBO и Cinemax. Аудитория HBO в США — более 40 млн. подписчиков. Кроме телевещания, HBO предлагает также видео на заказ и другие медиа-услуги. Подразделения HBO и совместные предприятия с её участием вещают более чем в 50 странах мира. Передачи производства HBO (главным образом телесериалы) были закуплены более чем в 150 стран.

proceeding s – доклады, записки, труды

a broadband Internet access – широкополосный доступ в интернет

 

 

Digital Television

The first country to make a wholesale switch to digital over-the-air (terrestrial) broadcasting was Luxembourg, in 2006. Since then, the Netherlands, Finland, Andorra, Sweden, Switzerland, Belgium (Flanders), Germany, and the United States and have followed suit.

In the United States, over-the-air broadcasts are solely in the ATSC digital format since June 12, 2009, the date that the FCC set for the end of all analog TV transmissions. The switchover was originally scheduled for February 17, 2009 until the US Congress passed the DTV Delay Act. By special dispensation, some analog TV signals ceased on the original date and earlier in Hawaii.

In Japan, the switch to digital is scheduled to happen July 24, 2011. In Canada, it is scheduled to happen August 31, 2011. China is scheduled to switch in 2015. In the United Kingdom, the digital switchover has different times for each part of the country; however, the whole of the UK will be digital by 2012. Brazil switched to digital on December 2, 2007 in major cities and it is estimated it will take seven years for complete signal expansion over all of the Brazilian territory.

In Malaysia, the Malaysian Communications & Multimedia Commission (MCMC) will call for tender bids in the third quarter of 2009 for the UHF 470–742 megahertz spectrum which will pave the way for the country to move into the digital television era. The awarding of the spectrum will see the winner having to build a single digital terrestrial transmission/TV broadcast (DTTB) infrastructure for all broadcasters to ride on to transmit their TV programs. The winner will be announced at the end of 2009 or early 2010 and has to commence digital roll-out soon after the award where the analog switch-off is planned for 2015.

While the majority of the viewers of over-the-air broadcasting in the USA watch full-power stations (which number about 1800), there are three other categories of TV stations in the USA: low-power stations, Class A stations, and TV translator stations. There is presently no deadline for these stations, about 7100 in number, to convert to digital broadcasting.

Formats and bandwidth

Digital television supports many different picture formats defined by the combination of size, aspect ratio (height to width ratio) and interlacing. With terrestrial broadcasting in the USA, the range of formats can be coarsely divided into two categories: HDTV and SDTV.

High-definition television (HDTV), one of several different formats that can be transmitted over DTV, uses one of two formats: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlace mode (1080i). Each of these utilizes a 16:9 aspect ratio. (Some televisions are capable of receiving an HD resolution of 1920 × 1080 at a 60 Hz progressive scan frame rate — known as 1080p60, but this standard is not currently used for transmission.) HDTV cannot be transmitted over current analog channels.

Standard definition TV (SDTV), by comparison, may use one of several different formats taking the form of various aspect ratios depending on the technology used in the country of broadcast. For 4:3 aspect-ratio broadcasts, the 640×480 format is used in NTSC countries, while 720×576 (rescaled to 768×576) is used in PAL countries. For 16:9 broadcasts, the 704×480 (rescaled to 848×480) format is used in NTSC countries, while 720×576 (rescaled to 1024×576) is used in PAL countries. However, broadcasters may choose to reduce these resolutions to save bandwidth (e.g., many DVB-T channels in the United Kingdom use a horizontal resolution of 544 or 704 pixels per line). This is done through the use of interlacing, in which the effective vertical resolution is halved to 288 lines.

Each commercial terrestrial DTV channel in North America is permitted to be broadcast at a data rate up to 19 megabits per second, or 2.375 megabytes per second. However, the broadcaster does not need to use this entire bandwidth for just one broadcast channel. Instead the broadcast can be subdivided across several video subchannels of varying quality and compression rates, including non-video datacasting services that allow one-way high-bandwidth streaming of data to computers.

A broadcaster may opt to use a standard-definition digital signal instead of an HDTV signal, because current convention allows the bandwidth of a DTV channel (or "multiplex") to be subdivided into multiple subchannels (similar to what most FM stations offer with HD Radio), providing multiple feeds of entirely different programming on the same channel. This ability to provide either a single HDTV feed or multiple lower-resolution feeds is often referred to as distributing one's "bit budget" or multicasting. This can sometimes be arranged automatically, using a statistical multiplexer (or "stat-mux"). With some implementations, image resolution may be less directly limited by bandwidth; for example in DVB-T, broadcasters can choose from several different modulation schemes, giving them the option to reduce the transmission bitrate and make reception easier for more distant or mobile viewers. Michael Bisk was instrumental in developing dual multiplexed RISC processors coupled with ultrafast 128-bit A/D converters for enhanced bandwidth LCD monitor reception. This is presently under prototype in the EU.

Reception

There are a number of different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is using an antenna (known as an aerial in some countries). This way is known as Digital Terrestrial Television (DTT). With DTT, viewers are limited to whatever channels the antenna picks up. Signal quality will also vary.

Other ways have been devised to receive digital television. Among the most familiar to people are digital cable and digital satellite. In some countries where transmissions of TV signals are normally achieved by microwaves, digital MMDS is used. Other standards, such as DMB and DVB-H, have been devised to allow handheld devices such as mobile phones to receive TV signals. Another way is IPTV that is receiving TV via Internet Protocol, relying on DSL or optical cable line. Finally, an alternative way is to receive digital TV signals via the open Internet. For example, there is a lot of P2P Internet Television software that can be used to watch TV on your computer.

Some signals carry encryption and specify use conditions (such as "may not be recorded" or "may not be viewed on displays larger than 1m in diagonal measure") backed up with the force of law under the WIPO Copyright Treaty and national legislation implementing it, such as the U.S. Digital Millennium Copyright Act. Access to encrypted channels can be controlled by a removable smart card, for example via the Common Interface (DVB-CI) standard for Europe and via Point Of Deployment (POD) or named differently CableCard.

Advantages to conversion

DTV has several advantages over analog TV, the most significant being that digital channels take up less bandwidth (and the bandwidth needs are continuously variable, at a corresponding cost in image quality depending on the level of compression). This means that digital broadcasters can provide more digital channels in the same space, provide high-definition television service, or provide other non-television services such as multimedia or interactivity. DTV also permits special services such as multiplexing (more than one program on the same channel), electronic program guides and additional languages, spoken or subtitled. The sale of non-television services may provide an additional revenue source.

Digital signals react differently to interference than analog signals. For example, common problems with analog television include ghosting of images, noise from weak signals, and many other potential problems which, whilst degrading the quality of the image, don't necessarily degrade watchability. Digitized signals don't suffer from ghosting or noise because DTV Tuners and converter boxes receive numeric information by the antenna. The decoder only needs enough information to put the picture together. The only way it fails is when the decoder does not receive enough information from the antenna - there is too much interference in the signal for the decoder to read the number and produce the picture. This will render a digital signal unwatchable with much less interference than an analog signal, even in urban areas.~7118

 

Comments:

ATSC - Advanced Television Systems Committee - организация, разрабатывающая и утверждающая стандарты для передовых телевизионных систем, в том числе и HDTV. Наиболее широко стандарты ATSC распространены в США и Канаде.

FCC - Federal Communications Commission - Федеральная Комиссия по коммуникациям. Независимое правительственное агентство Соединенных Штатов, созданное, управляемое и уполномоченное в соответствии с уставом Конгресса.

a switchover - переключение, переход в другой режим

a dispensation - распределение, распространение

to cease - прекращать, переставать (делать что-л.)

a roll- out - свёртывание процесса; откачка; выгрузка (из оперативной памяти)

Class A station – класс телевизионное обслуживание. Система в Соединенных Штатах., которая регулирует некоторые телевизионные станции с низкой мощностью.

HDTV - High-Definition Television, телевидение высокой чёткости, или телевидение повышенной чёткости. Набор стандартов телевизионного вещания повышенного качества посредством цифровых каналов связи (кабельные, спутниковые сети, цифровые носители).

SDTV - Standard Definition TeleVision - телевидение с обычным (стандартным) разрешением, не более 576 строк.

pixel - пиксел, минимальный элемент изображения.

NTSC - National Television Standards Committee. Национальный комитет по телевизионным стандартам. Система аналогового цветного телевидения, разработанная в США. 18 декабря 1953 года впервые в мире было начато цветное телевизионное вещание с применением именно этой системы.

PAL - phase-alternating line — система аналогового цветного телевидения, разработана инженером немецкой компании «Telefunken» Вальтером Брухом и представленная как стандарт телевизионного вещания в 1967 году.

DVB- T - Digital Video Broadcasting — Terrestrial. Европейский стандарт наземного цифрового вещания, один из семейства стандартов DVB. Используется, прежде всего, в различных европейских, азиатских и африканских государствах, а также в Австралии как стандарт для передачи цифрового телевидения и радио.

a datacasting – распределение данных

a statistical multiplexer – статистический мультиплексор,коммутатор,селектор, переключатель

a n implementation – реализация, выполнение

a bitrate - битрейт - это количество передаваемой информации за единицу времени. Или, применительно к сети Интернет и файлам, битрейт - это сколько бит или байт расходуется на одну секунду записи. Чаще всего битрейт указывается в килобитах (kbps или kbit/s).

RISC -Reduced Instruction Set Computer - вычисления с сокращённым набором команд.

A/ D converter – преобразователь переменного тока в постоянный ток

LCD ( liquid crystal display) - жидкокристаллический дисплей (ЖК-дисплей). Плоский дисплей на основе жидких кристаллов, а также монитор на основе такого дисплея.

MMDS - Multichannel Multipoint Distribution Service – Многоканальная многоадресная распределенная служба, относится к технологии фиксированных беспроводных сетей и использует микроволновый диапазон частот 2,5-2,7 Ггц

DMB - Digital Multimedia Broadcasting - это технология, позволяющая передавать цифровой сигнал на мобильные устройства, такие как мобильный телефон или КПК, что позволяет прослушивать на них радио и смотреть телевизионные программы.

DVB - H - Digital Video Broadcasting – Handheld. Технология мобильного вещания, позволяющая передавать цифровой видеосигнал на мобильные устройства, такие как КПК, мобильный телефон или портативный телевизор. IPTV - Internet Protocol Television. Технология IPTV (IP-TV, IP-телевидение). Цифровое интерактивное телевидение в сетях передачи данных по протоколу IP, новое поколение телевидения.

Internet Protocol (IP) - межсетевой протокол. Маршрутизируемый сетевой протокол, основа стека протоколов TCP/IP.

P2P (peer-to-peer) — точка-точка. Однора́нговые, децентрализо́ванные или пи́ринговые компьютерные сети, основанные на равноправии участников. В таких сетях отсутствуют выделенные серверы, а каждый узел (peer) является как клиентом, так и сервером.

a n encryption – шифрование, шифровка

WIPO Copyright Treaty - World Intellectual Property Organization Copyright Treaty - международное соглашение по охране авторского права, разработанное Всемирной организацией интеллектуальной собственности (ВОИС) и принятое на Дипломатической конференции организации 20 декабря 1996 года.

Digital Millennium Copyright Act - Закон об авторском праве в цифровую эпоху, дополняющий законодательство США в области авторского права директивами, учитывающими современные технические достижения в области копирования и распространения информации.

CableCard – карта приблизительно имеет размер кредитной карточки. Она позволяет потребителям в Соединенных Штатах просматривать и делать запись каналов с цифрового кабельного телевидения на цифровых видеомагнитофонах и персональных компьютерах без использования другого оборудования.

to render - приводить в какое-л. состояние, изменять состояние

 

 

Digital Video

With digital video we are able to take two of our senses, sight and sound, convert the analog signals, and combine them in the digital realm. By converting our analog world into the digital realm, we can more easily manipulate sight and sound.

Our vision is inherently analog based. To convert that analog world to a digital one, we need a device to sample analog signals and convert them into the digital domain. This is done using a Charged Coupled Device (CCD). A CCD performs sampling and outputs digital information. Once an image is captured, raw video is converted to more efficient formats that can be manipulated, transported, and stored. In order for businesses to take advantage of the benefits of digital video and to make digital video applications more affordable to implement, numerous compression techniques have been developed. Video compression methodologies take the original, raw video data and shrink it using methods that can either restore the video back to its original state called lossless compression when uncompressed or to a close approximation to the original called lossy compression.

Historically, video transmission (synchronous video with audio) was accomplished using traditional analog communication techniques over a coaxial cable physical infrastructure. For both residential and business environments this typically means supporting overlay networks. In addition to the added costs associated with designing, implementing, and maintaining separate networks, video networks have became increasingly complex as the size of the video network increases. Once the video signal (synchronous video with audio) has been digitized, transporting this signal over a communications network based on standard networking technologies like ATM and Ethernet/IP becomes much easier and cost effective for most businesses and even residential video service delivery. However, due to the latency requirements for video signals, the supporting network infrastructure must exhibit several key characteristics discussed below.

One of the most difficult tasks is to determine the level of video quality that is adequate and required for a certain need. Needs range from video conferencing in a business environment to video surveillance in a public safety environment, to broadcasting for entertainment purposes. The trade-off surrounds quality versus cost, and it centers on the level of video quality necessary to achieve the desired level of realism from the video transmission. These decisions cover the range of digital video solution components discussed above. Cameras, viewing devices, compression methods, and appropriate network infrastructure must be designed and selected to ensure that your video will meet user’s expectations. Regarding the network infrastructure segment of the overall digital video solution, latency is the main issue. Latency in networking is the amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network. In order to address the latency requirements of high-quality digital video transmission, a network based on ATM provides the best solution on the market today. ATM is an International Telecommunications Union – Telecommunication Standardization Sector (ITU-T) standard for cell relay. Cells are the basic unit of transferring data in an ATM network. It is fixed sized and contains destination information and payload. Since the cells are of fixed size, exacting algorithms have been invented to ensure that when data is sent, it will arrive at the appropriate destination intact, with minimal jitter. This trait is better known as Quality of Service (QoS). Today, ATM is the accepted standard technology for video networking. While there are many IP video solutions available on the market today, only ATM can provide the necessary features to support video transmission flawlessly. Since video is very loss and jitter sensitive, ATM QoS guarantees video transmissions will arrive at the destination address intact.

    Another main attribute necessary for digital video transmission is network reliability. Network reliability affects latency. In the event of a network outage due to an equipment failure or physical layer problem, the network supporting digital video transmission must be robust enough to identify the outage point and re-route traffic so no interruption in service is noticed by the users. Digital video networks based on ATM technology have an inherent advantage over Ethernet-based networks due to a robust, hierarchical routing protocol called Private Network to Network Interface (PNNI). Network infrastructures leveraging PNNI technology have the proven ability to re-route traffic within 50ms of an outage. This more than supports the latency requirements of digital video. Conversely, IP/Ethernet networks based on RIP and OSPF routing protocols can take up to 30 seconds to re-route traffic due to an outage. This delay will result in unacceptable video service interruptions. Finally, ATM technology has been widely accepted as the network technology of choice in every telecommunication service provider’s network. ~ 4409

 

 

Comments:

CCD (Charged Coupled device) –прибор с зарядовой связью, ПЗС

a raw video – необработанное телевидение

affordable - допустимый

to shrink - уменьшать, сокращать

ATM - Asynchronous Transfer Mode — асинхронный способ передачи данных. Сетевая технология, основанная на передаче данных в виде ячеек (cell) фиксированного размера (53 байта), из которых 5 байтов используется под заголовок.

Ethernet- от лат. aether - эфир. Пакетная технология компьютерных сетей, преимущественно локальных.

a latency - время ожидания, латентность

ITU- T – Комитет по стандартизации телекоммуникаций в составе МСЭ. В недавнем прошлом CCITT (Comite Consultatif Internationale Telegraphique et Telephonique) – Международный консультативный комитет по телефонии и телеграфии (МККТТ). Переименован в Сектор стандартизации телекоммуникаций - TSS (Telecommunications Standardization Sector). В задачи ITU-T входит установление стандартов в области электросвязи. Членами комитета являются министерства связи стран - членов ООН, частные компании, научные организации и торговые объединения. Рекомендации по стандартам публикуются в книгах с цветовой кодировкой (1984 г. - "Красная книга", 1988 г. - "Синяя книга", 1990 г. - "Розовая книга").

a payload - полезная нагрузка

a jitter – дрожание

QoS ( Quality of Service ) – качество обслуживания, гарантированное качество обслуживания. Качество и класс услуг по передаче данных, предоставляемых пользователю АТМ - сетью. Мера производительности телефонной системы, касающаяся качества линий и количества блокировок вызовов.

a n outage – бездействие, выход из строя; аварийное отключение

PNNI (Private Network- to- Network Interface) – межсетевой интерфейс частных сетей. Спецификация Форума ATM, определяющая методы маршрутизации.

to leverage - усиливать, использовать рычаги (для усиления)

RIP (Routing Information Protocol) – протокол маршрутной информации, протокол RIP. Протокол, применяемый в маршрутизаторах для динамического обмена данными о расположении маршрутизаторов в сети. Определён в RFC 1388 и 1723. В нем вычисляется, сколько переходов через другие маршрутизаторы будут включать в себя разные пути. Выбирается путь с минимальным числом переходов.

OSPF ( Open Shortest Path First ) –открытый протокол предпочтения кратчайшего пути. Стандарт, разработанный комитетом IETF для маршрутизаторов сети Internet. Применяется для определения оптимального маршрута. Основан на алгоритме SPF. Обеспечивает следующие дополнительные возможности: маршрутизацию пакета в соответствии с заказанным типом обслуживания; равномерное распределение нагрузки между альтернативными путями одинаковой стоимости; аутентификацию маршрутизаторов, гарантирующую защиту от злоумышленников; задание виртуального канала между маршрутизаторами, соединенными не напрямую, а через некоторую транзитную сеть.