|
[[Image:Braun HF 1.jpg|thumb|left|[[Braun (company)|Braun HF 1]], [[Germany]], 1959]]
[[Image:Fernseher.jpg|thumb|Clivia II FER858A (VEB Rafena, Radeberg, Germany), 1956]]
ټلوېزون يوه داسې اله ده ، چې د غږ او انځور په مرسته پيغام خپروي. د ټلوېزيون ايجاد او د خپرونو پيل په خپل شاليد کې يو پر زده پورې تاريخ لري. ټلوېزيون ته د نوي پېر نړۍ هېنداره ويلاى شي. د ټلوېزون له لارې موږ پر کور ناست د نړۍ چکر وهو او په نړۍ کې د پېښې شوې مهمې او ارزښتمنې پېښې په خپلو سترګو وينو. ټلوېزيون پروګرام تر موږ پورې له کوم ټلوېزون سټېشن څخه را رسېږي، چې ټلوېزون مرکز ورته ويل کېږي. ځينې پروګرامونه له ټلوېزون مرکز پرته نيغ په نيغه هم خپرېږي. دغه خپرونې د کامرو او فيته ثبتوونکيو( Tape Recorders) په مرسته خوندي کېږي هم او د اړتيا پر مهال د ټلوېزون مرکزونو څخه بيا خپرېږېداى شي. د ټلوېزون د ايجاد او خپرونو په اړه پر تفصيلاتو له پوهېدنې تر مخه د ټلوېزون پر معنى او مفهوم پوهيدنه اړينه ده.
== ټلوېزون څه شى دى؟ ==
ټلوېزون ( Television) د دوه کلېمو مجموعه ده. چې ټېلي ( Tele) او وېژن ( Vision). ټېلي ( Tele) يوه رومي کلېمه ده او د ډېر لرې ( For Away) معنى لري، او وېژن ( Vision) د ليدلو معنى لري. نو په دې توګه ټلوېزون د ( له لرې ليدل) يا ( له لرې سيل کول).معنى لري.
== د ټلوېزون رامېنځ ته کېدنه ==
د ټلوېزون منځ ته راتګ( اختراع) په يو وار يا ناڅاپي ډول نه ده شوې. د هغې شاليد کې د برېښنايي اختراعاتو د بري يوه لړۍ پرته ده. د ټلوېزون له اختراع تر مخه ساينس پوهان په دې نظر وو چې د هوا د څپو له لارې له يو ځايه بل ځاى ته د غږ او انځور تګ يا لېږدول شوني ( ممکن) دي. دې نظريې ته د عملي شکل ورکولو لپاره پر ١٨٩٤ز کال يو ساينس پوه راډيوي غږونه په برياليتوب سره تر يو لنډ واټن پورې ورسول. دغه ساينس پوه ګاليلو مارکوني و، چا چې راډيو اختراع کړه. په ١٩مه پېړۍ کې ټېليګراف اختراع شو. ورپسې د ټېليفون له اختراع سره سم د غږ لېږدول ( Transmission) پيل شو.
د ټلوېزون ستره اختراع د سکاټلينډ يو اوسېدونکي جان لوګي بيرډ (John Logie Baired) وکړه. بيرډ به ډېر ځلې ( اکثر) فکر کاوه، چې لکه څرنګه چې له تار پرته زموږ غږ له يوه ځايه بل ځاى ته رسېږي، دغسې انځور هم رسولاى شو. دغې خيال ته د حقيقي شکل ورکولو لپاره بيرډ تجربې پيل کړې. له تجربو څخه دې پايلې ( نتيجې) ته ورسېد چې بې شمېره تورې او سپينې کوچنۍ نقطې د برېښنا په ذريعه له يوه ځايه بل ځاى ته لېږدول کېداى شي. دغه نقطې د يو بل ماشين په واسطه يو وار بيا يو ځاى د انځور په توګه پر پرده ښودل کېداى شي.
جان بيرډ پر ١٩٢٥ز کال له يوې کامرې څخه بلې کامرې ته پر يوه پرده د يو ماشوم د تصوير په لېږدولو بريالى شو. جان بيرډ پر ١٩٢٧ز کال تر ګلاسکو پورې د لندن ښار د منظرو په لېږدونه بريالى شو.
پر ١٩٢٩ز د ټلوېزون لومړنى خپرنيز مرکز په لندن کې پرانيستل شو. د ټلوېزون اختراع کوونکي جان لوګي بيرډ پر ١٩٤٦ز مړ شو.
له بله پلوه جرمني ساينس پوهانو د دوهمې نړيوالې جګړې پر مهال له سل ميلو لرې واټن څخه پر "٢٤ x "١٨پرده د انځورونو د ترلاسه کولو بريالۍ تجربه تر سره کړې وه. خو په نړيواله جګړه کې د هېټلر له ناکامۍ وروسته هغوى دې لوري ته پاملرنه و نه کړه.
== د ټلوېزون خپرونې ==
په نړۍ کې دمنظمو ټلوېزوني خپرونو پيل له ټولو تر مخه په انګلستان کې وشو. د جان بېيرډ لومړنۍ ټلوېزوني خپرونې د ١٩٢٥ز کال د سپټمبر پر ٣٠ مه نېټه د بي بي سي له خپروونکې ماشين ( Transmeter) له لارې خپرې شوې. وروسته بيا د پرلپسې منظمو خپرونو چارې هم بي بي سي ( British Broadcasting Corporation ) پر غاړه واخيستې، خو د دويمې نړيوالې جګړې له امله دغه خپرونې بندې کړاې شوې.
له دويمې نړيوالې جګړې وروسته پر ١٩٤٦ز کال د ټلوېزون خپرونې بيا پيل شوې، او دايره يې له لندن څخه پراخه او نورو سيمو ته وغزېده.
په لندن کې د برياليو ټلوېزوني خپرونو د امريکې پر متحده ايالاتو هم اغېزه وکړه او هغوى هم د ټلوېزون د خپرونو پر تجربو لاس پورې کړ.
{{otheruses}}
{{redirect|TV}}
[[Image:Braun HF 1.jpg|thumb|left|210px|[[Braun (company)|Braun HF 1]], [[Germany]], [[1959]]]]
'''Television''' (often abbreviated to '''TV''', '''T.V.''', or '''t.v.''' and sometimes called '''The Tube''', or '''telly''' in the [[UK]]) is a widely used [[telecommunication]] system for [[broadcasting]] and receiving [[Film|moving picture]]s and [[sound]] over a distance. The term may also be used to refer specifically to a television set, [[television program|programming]] or television [[Transmission (telecommunications)|transmission]]. The word is derived from mixed [[Latin]] and [[Greek language|Greek]] roots, meaning "far sight": Greek ''{{polytonic|τῆλε}}'' "tele", far, and Latin ''vision'', sight (from ''video, vis-'' to see).
Since it first became [[History of television#Broadcast television|commercially available from the late 1930s]], the television set has become a common household communications device in homes and institutions, particularly in the [[first world]], as a source of entertainment and news. Since the 1970s, [[video]] recordings on VCR tapes and later, digital playback systems such as [[DVD]]s, have enabled the television to be used to view recorded movies and other programs.
A television system may be made up of multiple components, so a screen which lacks an internal [[tuner]] to receive the broadcast signals is called a monitor rather than a television. A television may be built to receive different broadcast or video formats, such as High-Definition television ([[HDTV]]).
==تخينک==
===د ټلويزوني غونډال توکي===
[[Image:OTVbelweder-front.jpg|250px|thumb|right|[[Belweder (TV set)|OT-1471 Belweder]], [[People's Republic of Poland|Poland]], 1957<small><br>
{{col-begin}}
{{col-break}}
1. power switch / volume<br>
2. brightness<br>
3. pitch<br>
4. vertical synchro<br>
{{col-break}}
5. horizontal synchro<br>
6. contrast<br>
7. channel tuning<br>
8. channel switch</small>
{{col-end}}]]
The elements of a simple television system are:
* An image source - this may be a [[Professional video camera|camera]] for live pick-up of images or [[VTR]] or a [[Film Chain]]-[[Telecine]]-[[flying spot scanner]] for transmission of [[motion picture|films]].
* A sound source picked up by a microphone
* A [[transmitter]], which modulates one or more television signals with both picture and sound information for transmission.
* A receiver (also called a [[tuner]]) which recovers and processes the picture and sound signals from the television broadcast signal.
* A display device, which turns the electrical signals into visible light and images
* A small [[amplifier]] and [[loudspeaker]], which turns electrical signals into sound waves (speech, music, and other sounds) to accompany the images.
Practical television systems include equipment for selecting different image sources, mixing images from several sources at once, insertion of pre-recorded video signals, synchronizing signals from many sources, and direct image generation by [[computer]] for such purposes as station identification.
Transmission was originally over the air from land-based transmitters. The quality of reception varies greatly, and this led to the proliferation of large antennas on house roofs for best signal in the 1960s. In most cities today, cable systems deliver television over metal or optical cables, but for a fee. It can be delivered by radio from synchronous [[Satellite television|satellite]]s, which were large for analog, and smaller dishes for digital broadcast, also for a fee, often less than cable systems, which has led to the appearance of small dishes outside of houses and apartments.
Digital systems may be inserted anywhere in the chain to provide better image transmission quality, reduction in transmission [[bandwidth]], special effects, or security of transmission from reception by non-subscribers. A home today might have the choice of receiving analog or HDTV over the air, analog or digital cable with HDTV from a cable television company over coaxial cable, or even from the phone company over fiber optic lines. On the road, television can be received by pocket sized televisions, recorded on tape or digital media players, or played back on wireless phones over a high speed network or the internet.
<!-- Elements of a television system - block diagram here -->
<!-- Image source, camera, film, magnetic tape, exceptionally computer-generated images-->
<!-- Sound source -->
<!-- Transmitter, over the air, bandwidth required, antenna, satellite system, cable system, digital encoding, scrambling -->
<!-- Receiver, antenna, cable connection, satellite down-converter, digital decode, descramble-->
<!-- Display, cathode ray tube, color tube, now LCD, historically mechanical scanned lamp-->
<!-- Recorder, analogue magnetic tape, now digital (DVD) -->
[[Image:Dv schnittplatz.JPG|thumb|250px|[[Digital video]] equipment in an edit suite]]
{{seealso|Liquid crystal display television}}
Thanks to the advances in display technology, there are now several kinds of video displays used in modern TV sets:
*'''CRT''' ([[cathode-ray tube]]): The most common screens were direct-view CRTs for up to roughly 100 cm (40 inch) (in 4:3 ratio) and 115 cm (45 inch) ((in 16:9 ratio) [[diagonal]]s. These are the least expensive, and are a refined technology that can still provide the best overall picture quality value. As they do not have a fixed [[native resolution]], they are capable of displaying sources with different resolutions at the best possible image quality. The [[frame rate]] or refresh rate of a typical [[NTSC]] format CRT TV is 29.97 Hz, and for the [[PAL]] format, 25 Hz, both are scanned with two fields per frame in an [[interlace]]d fashion. A typical [[NTSC]] broadcast signal's visible portion has an equivalent resolution of about 640x480 pixels. It actually could be slightly higher than that, but the [[vertical blanking interval]] (VBI), allows other signals to be carried along with the broadcast. High [[lead]] content.
*'''Rear projection''' ('''RPTV'''): Most very large screen TVs (to 100 inches [254 cm] or more) use [[projection]] technology. Three types of projection systems are used in projection TVs: CRT-based, [[Liquid crystal display|LCD]]-based, and [[DLP]] (reflective micromirror chip) -based. Projection television has been commercially available since the 1970s, but at that time could not match the image sharpness of the CRT; current models are vastly improved, and offer a cost-effective large-screen display.
**A variation is a '''[[video projector]]''', using similar technology, which projects onto a [[Projection screen|screen]].
[[Image:CeBIT 2006 Philips 3D Display 42 3D6W01 WOW Richardson Electronics KUKFilm 1298 by HDTVTotalDOTcom.jpg|thumb|right|250px|A modern Philips LCD TV]]
*'''Flat panel''' ([[LCD]] or [[Plasma display|plasma]]): Modern advances have brought [[Flat panel display|flat panel]]s to TV that use [[Active-matrix liquid crystal display|active matrix]] [[liquid crystal display|LCD]] or [[plasma display]] technology. Flat panel LCDs and [[plasma display]]s are as little as 25.4 mm (1 inch) thick and can be hung on a wall like a picture or put over a [[pedestal]]. Some models can also be used as [[Computer display|computer monitor]]s.
*'''LED''' technology has become one of the choices for outdoor video and stadium uses, since the advent of bright [[Light-emitting diode|LED]]s and driver circuits. LEDs enable scalable ultra-large [[Light-emitting diode#LED display panels|flat panel video displays]] that other technologies may never be able to match in performance.
Each has its pros and cons. Flat panel LCD and plasma displays have a wide viewing angle (around 160 degrees) so they may best suited for a home theatre with a wide seating arrangement. Rear projection screens do not perform well in [[daylight]] or well-lit rooms and so are only suited to darker viewing areas. A comparison of these technologies is available [[Comparison of display technology|here]].
=== د ټلوېزيون ټرمينالوجي ===
پکسل (د ښوديز ريزولوشن\ريزولوشن) پر يوه پرده د څانګړيو ټکيو شمېر دی، چې [پکسل] بلل کېږي.د پکسل د کلمې استعمال خورا نوی دی، او نېټه يې هغه وخت ته رسېږي، چې د [VGA] ښوديز معيار وپېژندل شو. له ۱۹۸۰مې لسيزې مخکې "lines of resolution" د رېزولوشن د اندازه کولو معياري يوون (واحد) و.
د 720x480 يو دوديز رېزولوشن معنا داده، چې د ټلوېزيون ښوديز ۷۲۰ پکسلونه په افقي او ۴۸۰ پکسلونه په عمودي محور باندې لري. څومره، چې د يو څانګړي ښوديز رېزولوشن زیات وي، همغومره انڅور ښه وي. کانټرسټ [تناسب] پر پرده د روښانوالي او تیاره والي د ټکيو تر منڅ د فاصلې د اندازه کولو واحد دی.
څومره، چې د کانټرسټ تناسب لوړ وي، همغومره انڅور بډای، ژور او سيوری لرونکی ښکاري. د انڅور روښانوالی دا اندازه کوي، چې رنګونه څومره خوڅند او اغېزمن دي. د هغو شمعو، چې د انڅور د بلولو\غښتلولو لپاره په کار دی، سره په مساوي کچه اندازه کېږي.
له بلې خوا، پر ټلوېزیونونو او مونيټورونو د "روښانوالی" او "کانټرسټ" برابروونکي څارونه (adjustment controls)، د انڅور د ښوديز د بېلابېلو برخو د څارنې لپاره کارېږي.
د روښانوالي څار تور ټکی، یا د سيوري کچه، خوڅوي، چې د کانټرسټ تناسب يا د انڅور ګاما اغېزمنوي، خو د کانټرسټ څار د انڅور قوت يا روښانوالی څاري.
اخڅ: جان واټکېنسن، " Convergence in Broadcast and Communications Media: The Fundamentals of Audio, Video, Data'', Focal Press, 2001, ISBN 0240515099"
===Transmission band===
There are various bands on which televisions operate depending upon the country. The [[VHF]] and [[UHF]] signals in bands III to V are generally used. Lower frequencies do not have enough [[bandwidth]] available for television. Although the [[BBC]] initially used Band I VHF at 45 MHz, this frequency is (in the UK) no longer in use for this purpose. Band II is used for FM radio transmissions. Higher frequencies behave more like light and do not penetrate buildings or travel around obstructions well enough to be used in a conventional broadcast TV system, so they are generally only used for [[MMDS]] and [[satellite television]], which uses frequencies from 2 to 12 GHz. TV systems in most countries relay the video as an AM ([[amplitude-modulation]]) signal and the sound as a FM ([[frequency-modulation]]) signal. An exception is [[France]], where the sound is AM.
===Aspect ratios===
'''[[Aspect ratio (image)|Aspect ratio]]''' refers to the ratio of the horizontal to vertical measurements of a television's picture. Mechanically scanned television as first demonstrated by [[John Logie Baird]] in 1926 used a 7:3 vertical aspect ratio, oriented for the head and shoulders of a single person in close-up.
Most of the early electronic TV systems from the mid-1930s onward shared the same [[aspect ratio (image)|aspect ratio]] of 4:3 which was chosen to match the [[Academy ratio|Academy Ratio]] used in cinema films at the time. This ratio was also square enough to be conveniently viewed on round [[cathode ray tube|cathode-ray tube]]s (CRTs), which were all that could be produced given the [[manufacturing]] [[technology]] of the time. (Today's CRT technology allows the manufacture of much wider tubes, and the flat-screen technologies which are becoming steadily more popular have no technical aspect ratio limitations at all.) The [[BBC]]'s television service used a more squarish [http://tcc.members.beeb.net/tchistory.html 5:4] ratio from 1936 to [http://www.pembers.freeserve.co.uk/Test-Cards/Test-Card-Technical.html#Aspect-Ratio 3 April 1950], when it too switched to a 4:3 ratio. This did not present significant problems, as most sets at the time used round tubes which were easily adjusted to the 4:3 ratio when the transmissions changed.
In the early 1950s, [[movie studio]]s moved towards [[widescreen]] aspect ratios such as [[CinemaScope]] in an effort to distance their product from television. Although this was initially just a [[gimmick]], widescreen is still the format of choice today and square aspect ratio movies are rare. Some people argue that widescreen is actually a disadvantage when showing objects that are tall instead of [[panorama|panoramic]], others say that natural vision is more panoramic than tall, and therefore widescreen is easier on the eye.
Yet the various television systems were not originally designed to be compatible with film at all. Traditional, narrow-screen movies are projected onto a television camera either so that the top of the screens line up to show facial features, or, for films with subtitles, the bottoms. What this means is that filmed newspapers or long captions filling the screen for explanation are cut off at each end. Similarly, while the frame rate of sound films is 24 per second, the screen scanning rate of the NTSC is 29.97 Hz, which requires complex scanning schedule. That of PAL and SECAM are 50 Hz, which means that films are shortened (and the sound is offkey) by scanning each frame twice for 25 per second.
The switch to [[digital television]] systems has been used as an opportunity to change the standard television picture format from the old ratio of 4:3 (1.33:1) to an aspect ratio of 16:9 (approximately 1.78:1). This enables TV to get closer to the aspect ratio of modern widescreen [[film|movie]]s, which range from 1.66:1 through 1.85:1 to 2.35:1. There are two methods for transporting widescreen content, the most common of which uses what is called [[full screen anamorphic|anamorphic widescreen]] format. This format is very similar to the technique used to fit a widescreen movie frame inside a 1.33:1 35 mm film frame. The image is compressed horizontally when recorded, then expanded again when played back. The anamorphic widescreen 16:9 format was first introduced via European [[PALPlus]] television broadcasts and then later on "widescreen" [[DVD]]s; the [[ATSC]] [[High-definition television|HDTV]] system uses straight widescreen format, no horizontal compression or expansion is used.
Recently "widescreen" has spread from television to computing where both [[desktop computer|desktop]] and [[laptop]] computers are commonly equipped with widescreen displays. There are some complaints about distortions of movie picture ratio due to some DVD playback software not taking account of aspect ratios; but this may subside as the DVD playback software matures. Furthermore, computer and laptop widescreen displays are in the 16:10 aspect ratio both physically in size and in pixel counts, and not in 16:9 of consumer televisions, leading to further complexity. This was a result of widescreen computer display engineers' assumption that people viewing 16:9 content on their computer would prefer that an area of the screen be reserved for playback controls, [[subtitles]] or their Taskbar, as opposed to viewing content full-screen.
=====Aspect ratio incompatibility=====
The television industry's changing of [[Aspect ratio (image)|aspect ratio]]s is not without difficulties, and can present a considerable problem.
Displaying a widescreen aspect (rectangular) image on a conventional aspect (square or 4:3) display can be shown:
*in "[[letterbox]]" format, with black horizontal bars at the top and bottom
*with part of the image being cropped, usually the extreme left and right of the image being cut off (or in "[[pan and scan]]", parts selected by an operator or a viewer)
*with the image horizontally compressed
A conventional aspect (square or 4:3) image on a widescreen aspect (rectangular with longer horizon) display can be shown:
*in "[[pillar box (film)|pillar box]]" format, with black vertical bars to the left and right
*with upper and lower portions of the image cut off (or in "tilt and scan", parts selected by an operator)
*with the image horizontally distorted
A common compromise is to shoot or create material at an aspect ratio of 14:9, and to lose some image at each side for 4:3 presentation, and some image at top and bottom for 16:9 presentation. In recent years, the cinematographic process known as [[Super 35 mm film|Super 35]] (championed by [[James Cameron]]) has been used to film a number of major movies such as [[Titanic (1997 film)|''Titanic'']], ''[[Legally Blonde]]'', ''[[Austin Powers]]'', and ''[[Crouching Tiger, Hidden Dragon]]'' (see also: [[:Category:Films shot in Super 35|Films shot in Super 35]]). This process results in a camera-negative which can then be used to create both wide-screen theatrical prints, and standard "[[full screen]]" releases for television/VHS/DVD which avoid the need for either "[[letterbox]]ing" or the severe loss of information caused by conventional "[[pan-and-scan]]" cropping.
=== Sound ===
{{further|[[NICAM]], [[Multichannel television sound|MTS]], and [[Zweikanalton]]}}
=== Data ===
{{further|[[Teletext]]}}
=== The End of Analog Television broadcasting ===
NTSC
* In North America, the basic signal standards have been compatible enough since 1941, that even the oldest monochrome televisions can still receive color broadcasts in 2007.
* However, the United States Congress has passed a law which requires cessation of all conventional television broadcast signals by February 2009.
* After that date all [[NTSC]] standard televisions, with analog only tuners, will go dark unless fitted with digital [[ATSC]] tuners, and the spectrum previously occupied by those analog channels will be auctioned off by the United States' Federal Communications Commission for other uses.
PAL & SECAM
* PAL and SECAM are expected to not be broadcast in Europe and Eurasia by the mid-2020s.
* PAL-M may have a similar decommissioning timeline.
=== Television add-ons ===
ټلويزيون د انځور ښودنې لپاره لومړی کاريدونکی ډليز بازار و.
The television was the first consumer mass market for video displays. Today there are many television add-ons including [[video game]] consoles, [[Videocassette recorder|VCR]]s, [[Set-top box]]es for [[Cable television|Cable]], [[Satellite television|Satellite]] and DVB-T compliant [[Digital Television]] reception, [[DVD]] players, or [[Digital video recorder|Digital Video Recorders]] (including personal video recorders, PVRs). The add-on market continues to grow as new technologies are developed. Computers, the internet, and even pocket devices such as the iPod provide other ways to consume video content.
=== New developments ===
{{col-begin}}
{{col-break}}
* [[Ambilight]]™
* [[Broadcast flag]]
* [[CableCARD]]™
* [[DLP|Digital Light Processing]] (DLP)
* [[Digital Rights Management]] (DRM)
* [[Digital television]] (DTV)
* [[Digital Video Recorder]]s (DVR)
* [[Direct Broadcast Satellite]] TV (DBS)
* [[DVD]] and [[HD DVD]] standards
* [[Blu-ray Disc]]
* [[Flicker-free]] (100 Hz or 120 Hz, depending on country)
* [[High Definition TV]] (HDTV)
* [[High-Definition Multimedia Interface]] (HDMI)
* [[IPTV]] also know as [[Internet television]]
* [[Laser TV]] display technology
{{col-break}}
* [[Liquid crystal display television|LCD]] and [[plasma display]] [[flat panel display|flat screen]] TV
* [[Surface-conduction electron-emitter display|SED]] display technology
* [[Organic light-emitting diode|OLED]] display technology
* [[P2PTV]]
* [[Pay-per-view]]
* [[Personal video recorder]]s (PVR)
* [[Picture-in-picture]] (PiP)
* [[Pixelplus]]
* [[Placeshifting]]
* [[Remote control]]s
* The [[Slingbox]]
* [[time shifting|Timeshifting]]
* [[Video on-demand]] (VOD)
* [[Ultra High Definition Video]] (UHDV)
* [[Web TV]]
{{col-break}}
[[Image:Hd tv samsung LE26R41BD.jpg|thumb|250px|right|[[Samsung Electronics|Samsung]] LE26R41BD [[High-definition television|HDTV]]]]
[[Image:100 01320.jpg|thumb|250px|right|A long screen television in Korea.]]
{{col-end}}
=== Exterior designs ===
In the early days of television, the cabinet was made of wood grain, however, the wood grain was disappearing in the 1980s. There has been a modern comeback of the woodgrain.<ref>[http://www.hannspree-usa.com/jump.jsp?itemID=25&itemType=PRODUCT&path=1%2C2%2C5%2C37&iProductID=25]</ref><ref>[http://www.retrothing.com/video_tv/index.html]</ref>
==Geographical usage==
*[[Timeline of the introduction of television in countries]]
{{main|Geographical usage of television}}
==Content==
===Programming===
{{seealso|:Category:Television genres}}
Getting TV programming shown to the public can happen in many different ways. After production the next step is to market and deliver the product to whatever markets are open to using it. This typically happens on two levels:
#'''Original Run''' or '''First Run''' - a producer creates a program of one or multiple episodes and shows it on a station or network which has either paid for the production itself or to which a license has been granted by the producers to do the same.
#'''[[Television syndication|Syndication]]''' - this is the terminology rather broadly used to describe secondary programming usages (beyond original run). It includes secondary runs in the country of first issue, but also international usage which may or may not be managed by the originating producer. In many cases other companies, [[TV stations]] or individuals are engaged to do the syndication work, in other words to sell the product into the markets they are allowed to sell into by contract from the copyright holders, in most cases the producers.
In most countries, the first wave occurs primarily on [[Free-to-air|free-to-air (FTA)]] television, while the second wave happens on subscription TV and in other countries. In the U.S., however, the first wave occurs on the FTA networks and subscription services, and the second wave travels via all means of distribution.
First run programming is increasing on subscription services outside the U.S., but few domestically produced programs are syndicated on domestic FTA elsewhere. This practice is increasing however, generally on digital-only FTA channels, or with subscriber-only first run material appearing on FTA.
Unlike the U.S., repeat FTA screenings of a FTA network program almost only occur on that network. Also, [[Affiliate]]s rarely buy or produce non-network programming that isn't centred around local events.
===Advertising===
Since inception in the US in 1940, [[television commercial|TV commercial]]s have become one of the most effective, most persuasive, and most popular methods of selling products of many sorts, especially consumer goods. US [[advertising]] rates are determined primarily by [[Nielsen Ratings]].
== Social aspects ==
===Technology trends===
In its infancy, television was an ephemeral medium. Fans of regular shows planned their [[TV listings|schedules]] so that they could be available to watch their shows at their time of broadcast. The term ''appointment television'' was coined by marketers to describe this kind of attachment.
The viewership's dependence on schedule lessened with the invention of programmable video recorders, such as the [[Videocassette recorder]] and the [[Digital video recorder]]. Consumers could watch programs on their own schedule once they were broadcast and recorded. Television service providers also offer [[video on demand]], a set of programs which could be watched at any time.
Both [[mobile phone]] networks and the [[Internet]] are capable of carrying video streams. There is already a fair amount of Internet TV available, either live or as downloadable programs, and video sharing websites have become greatly popular.
The Japanese manufacturer Scalar has developed a very small TV-system attached to the eyeglasses, called "Teleglass T3-F".<ref>
([http://www.reuters.com/article/lifestyleMolt/idUSSP849520070522])</ref>
===Suitability for audience===
Almost since the medium's inception there have been charges that some programming is, in one way or another, inappropriate, [[offensive]] or [[decency|indecent]]. Critics such as Jean Kilborne have claimed that television, as well as other mass media images, harm the self image of young girls. Other commentators such as [[Sut Jhally]] make the case that television advertisers in the U.S. deliberately try to equate happiness with the purchasing of products, despite studies which show that happiness for most people comes from non-material realms, such as warm friendships and feelings of connection to one's community.<ref>Jhally, Sut, [http://www.sutjhally.com/onlinepubs/apocalypse.html Advertising at the Edge of the Apocalypse]</ref> [[George Gerbner]] has presented evidence that the frequent portrayals of crime, especially minority crime, has led to the [[Mean World Syndrome]], the view among frequent viewers of television that crime rates are much higher than the actual data would indicate. In addition, a lot of television has been charged with presenting propaganda, political or otherwise, and being pitched at a low intellectual level.
===Alleged dangers===
{{NPOV-section}}
Paralleling television's growing primacy in family life and society, an increasingly vocal chorus of legislators, [[scientist]]s and [[parent]]s are raising objections to the uncritical acceptance of the medium.{{Fact|date=February 2007}} For example, the [[Sweden|Swedish]] government imposed a total ban on advertising to [[children]] under twelve in 1991 (see [[advertising]]). Fifty years of research on the impact of television on children's emotional and social development<ref>Norma Pecora, John P. Murray, & Ellen A. Wartella, Children and Television (TV): 50 Years of Research, published by Erlbaum Press, June, 2006</ref> demonstrate that there are clear and lasting effects of viewing violence. In a recent study (February, 2006) published in the journal Media Psychology, volume 8, number 1, pages 25-37, the research team demonstrated that the brain activation patterns of children viewing violence show that children are aroused by the violence (increased heart rates), demonstrate fear (activation of the [[amygdala]]-the fight or flight sensor in the brain) in response to the video violence, and store the observed violence in an area of the brain (the [[posterior cingulate]]) that is reserved for long-term memory of traumatic events.
Another study has shown that watching television makes your brain produce beta brainwaves, the "trance" brainwaves common when people are in a deep sleep.
One of the reasons people campaign against TV is because of the activities people are not doing during the time that they watch it. Many campaigners believe that using up 3.5 hours a day on TV (UK and American average) is not worthwhile.
A [[23 February]] [[2002]] article in [http://www.sciam.com/print_version.cfm?articleID=0005339B-A694-1CC5-B4A8809EC588EEDF Scientific American] suggested that compulsive television watching, [[television addiction]], was no different from any other [[addiction]], a finding backed up by reports of withdrawal symptoms among families forced by circumstance to cease watching.
A longitudinal study [http://archpedi.ama-assn.org/cgi/content/abstract/159/7/614] in [[New Zealand]] involving 1000 people (from childhood to 26 years of age) demonstrated that "television viewing in childhood and adolescence is associated with poor educational achievement by 12 years of age". In other words, the more the child watched television, the less likely he or she was to finish school and enroll in a [[university]].
A study published in the [[Journal of Sexuality Research and Social Policy]] concluded that parental television involvement was associated with greater body satisfaction among adolescent girls, less sexual experience amongst both male and female adolescents, and that parental television involvement may influence self-esteem and body image, in part by increasing parent-child closeness.<ref> Deborah Schooler, Janna L. Kim, and Lynn Sorsoli [http://caliber.ucpress.net/doi/abs/10.1525/srsp.2006.3.4.49 Setting Rules or Sitting Down: Parental Mediation of Television Consumption and Adolescent Self-Esteem, Body Image, and Sexuality]
Sexuality Research and Social Policy: Journal of NSRC</ref>
In [[Iceland]], television broadcasting hours were restricted until 1984, with no television programs being broadcast on Thursday, or during the whole of July.
===Propaganda delivery===
Audiovisual media, including television, is the second most effective means of communication available to the psychological operator. Effectiveness is based on seeing and hearing the persuasive message. These media are an excellent means of transmitting persuasive messages and eliciting a high degree of recall.<ref>"Psychological Operations Field Manual No.33-1" published in August 1979 by Department of the Army Headquarters in Washington DC; and "Psychological Operations (PSYOP) Media Subcourse PO-0816" by The Army Institute for Professional Development, published in 1983</ref>
[[Propaganda]] can exist on [[news]], [[Current affairs (news format)|current affairs]] or [[talk show]] segments, as [[advertising]] or public-service announce "spots" or as long-running [[advertorials]]<ref>http://en.wikipedia.org/wiki/Propaganda#Techniques_of_propaganda_transmission</ref>.
==Educational advantages==
Despite this research, many media scholars today dismiss such studies as flawed. For one example of this school of thought, see [[David Gauntlett]]'s article "[http://www.theory.org.uk/david/effects.htm Ten Things Wrong With the Media 'Effects' Model]." Dimitri Christakis cites studies that who watched "Sesame Street" and other educational programs as preschoolers had higher grades, were reading more books, placed more value on achievement and were more creative. Similar, while those exposed to negative role models suffered, those exposed to positive models behaved better.<ref>[http://archives.seattletimes.nwsource.com/cgi-bin/texis.cgi/web/vortex/display?slug=tvoped22&date=20070222&query=television February 22, 2007 Smarter kids through television: debunking myths old and new By Dimitri Christakis Special to The Washington Post]</ref> Modern children can be exposed to much more history, news and science than previous generations when information was only available from newspapers and books.
== Environmental aspects ==
With high [[lead]] content in [[cathode ray tube|CRT]]s, and the rapid diffusion of new, flat-panel display technologies, some of which ([[LCD]]s) use lamps containing [[mercury (element)|mercury]], there is growing concern about [[electronic waste]] from discarded televisions. Related [[occupational health]] concerns exist, as well, for disassemblers removing copper wiring and other materials from CRTs. Further environmental concerns related to television design and use relate to the devices' increasing [[electrical energy]] requirements. <ref>[http://www.est.org.uk/uploads/documents/aboutest/Riseofthemachines.pdf Energy Saving Trust, ''The Rise of the Machines: A Review of Energy Using Products in the Home from the 1970s to Today'', London, July 3, 2006]</ref>
== افغاني ټلوېزيوني شبكې ==
**[[ننګرهار ملي ټلويزيون]]
**[[لمر ټلویزيون]]
**[[تمدن ټلويزيون]]
**[[نور ټلويزيون]]
** [http://www.arianatelevision.com/index.html آريانا ټلويزيوني شبكه]
** [http://www.aa-tv.com/ آريانا افغانستان]
** [[افغان ټي وي]]
** [http://www.nrta.org.af/ افغانستان ملي راډيو ټلويزيون]
** [[ايينه ټلويزيوني شبكه]]
** [[سيماى غوريان ټلويزيوني شبكه]]
** [http://www.shamshadtv.com/ شمشاد ټلوېزيوني شبكه]
** [http://www.tolo.tv طلوع ټلويزيوني شبكه]
==Further reading==
*[[Pierre Bourdieu]], ''On Television'', The New Press, 2001.
*Brooks, Tim and March, Earle, ''The Complete Guide to Prime Time Network and Cable TV Shows'', Ballantine, Eighth Edition, 2002.
*[[Jacques Derrida]], [[Bernard Stiegler]], ''Echographies of Television'', Polity Press, 2002.
*[[Jerry Mander]], ''Four Arguments for the Elimination of Television'', Perennial, 1978.
*[[Jerry Mander]], ''In the Absence of the Sacred'', Sierra Club Books, 1992, ISBN 0-87156-509-9. Makes the case that television programming transmitted by communications satellites is destroying unique local cultures all over the world
* [[Neil Postman]], ''[[Amusing Ourselves to Death]]: Public Discourse in the Age of Show Business''. Penguin USA, 1985. ISBN 0-670-80454-1
*Dr. Aric Sigman, ''Remotely Controlled: How Television Is Damaging Our Lives — And What We Can Do About It'', Vermilion, 2005.
*Beretta E. Smith-Shomade, ''Shaded Lives: African-American Women and Television'', Rutgers University Press, 2002.
* Dr. Alan. Taylor,''We, the media, Pedagogic Intrusions into US Film and Television News...'' ISBN 3631518528 Peter, Lang, Academic Book Publishers, 2005, pp. 418.
*David E. Fisher and Marshall J. Fisher, ''Tube: the Invention of Television'', Counterpoint, Washington, D.C., USA, (1996) ISBN 1-887178-17-1
*Albert Abramson, ''The History of Television, 1942 to 2000'', McFarland, Jefferson, NC, USA, and London (2003) ISBN 0-7864-1220-8
*Evan I. Schwartz, ''The Last Lone Inventor: A Tale of Genius, Deceit, and the Birth of Television''
==References==
<!-- ----------------------------------------------------------
See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a
discussion of different citation methods and how to generate
footnotes using the <ref>, <;/ref> and <reference /> tags
----------------------------------------------------------- -->
<div class="references-small">
<references />
</div>
== Related websites ==
* [http://www.earlytelevision.org Early Television Foundation and Museum]
* [http://www.tvhistory.tv/ Television's History — The First 75 Years]
* [http://www.museum.tv/archives/etv/index.html The Encyclopedia of Television] at the [[Museum of Broadcast Communications]]
* [http://www.mztv.com MZTV Museum of Television] Some of the rarest sets in America
{{portalpar|Electronics|Nuvola_apps_ksim.png}}
{{Video formats}}
{{sisterlinks|Television}}
[[Category:Television| ]]
[[Category:Video hardware]]
[[Category:Media by format]]
[[af:Televisie]]
[[ang:Feorrsīen]]
[[ar:تلفزيون]]
[[zh-min-nan:Tiān-sī]]
[[bs:Televizija]]
[[bg:Телевизия]]
[[ca:Televisió]]
[[cs:Televize]]
[[cy:Teledu]]
[[da:Tv]]
[[pdc:Guckbax]]
[[de:Fernsehen]]
[[et:Televisioon]]
[[el:Τηλεόραση]]
[[es:Televisión]]
[[eo:Televido]]
[[eu:Telebista]]
[[fa:تلویزیون]]
[[fr:Télévision]]
[[ga:Teilifís]]
[[ko:텔레비전]]
[[hr:Televizija]]
[[io:Televiziono]]
[[id:Televisi]]
[[is:Sjónvarp]]
[[it:Televisione]]
[[he:טלוויזיה]]
[[ku:Televîzyon]]
[[la:Televisio]]
[[lv:Televīzija]]
[[lb:Televisioun]]
[[lt:Televizija]]
[[hu:Televízió]]
[[ms:Televisyen]]
[[nl:Televisie]]
[[ja:テレビ]]
[[no:Fjernsyn]]
[[ug:تېلېۋىزور]]
[[nds:Kiekschapp]]
[[pl:Telewizja]]
[[pt:Televisão]]
[[ro:Televiziune]]
[[ru:Телевидение]]
[[sco:Televeesion]]
[[sq:Televizioni]]
[[simple:Television]]
[[sk:Televízia]]
[[sl:Televizija]]
[[sr:Телевизија]]
[[fi:Televisio]]
[[sv:TV]]
[[tl:Telebisyon]]
[[ta:தொலைக்காட்சி]]
[[th:โทรทัศน์]]
[[vi:Tivi]]
[[tr:Televizyon]]
[[uk:Телебачення]]
[[fiu-vro:Televis'uun]]
[[yi:טעלעוויזיע]]
[[bat-smg:Televėzėjė]]
[[zh:电视]]
| 