Dtv air meaning

Dtv air meaning DEFAULT

DTV is Digital Television. Digital Television (DTV) is an advanced broadcasting technology that will transform your television viewing experience. You can get DTV in many ways. You can pay for it via cable or satellite, or you can get it free, directly from the broadcast (also known as, over-the-air) TV stations.

DTV in High Quality SD and HD
Most people think of broadcast TV as their grandparents’ rabbit ears that they were always adjusting, only to get fuzz! Gone are the days of snowy and ghosting images. With broadcast DTV, all channels are crystal-clear and sound great! When it comes to High Definition (HD), broadcast DTV, HD channels look better than paid TV services. DTV broadcasts stations don’t compress their signals like cable and satellite, so their HD programming has higher resolution, more detail, and crisper pictures. Best of all, it’s free.

Free DTV in Fresno and the Central Valley
Now that broadcast stations are digital, there are more channels than ever! In the United States, Fresno is second only to Los Angeles with the number of channels that are available for FREE! There are over 45 channels just in Fresno and more are coming soon! With the right antenna, Central Valley viewers can expand their viewable channels to include channels as far away as Bakersfield.

Broadcast DTV Offers Programming That You Love to Watch
You may not be aware of the multitude of free programming options now available. Central Valley broadcast TV viewers can now enjoy all the major networks including ABC, CBS, NBC, Fox, PBS, and TheHub, a joint venture between CBS, UPN, and Warner Bros. Additionally, viewers can view dedicated movie channels, Spanish and other foreign language networks, a world news network, family-oriented nostalgic and classic TV networks, NBC’s Universal Sports network, music video channels, religious, ethnic, and even shopping channels – all for free! Many of these channels are not even offered on the paid services.

What Channels Are Available?
Click here to check out the complete list of channels and descriptions.

The Digital TV (DTV) Transition
The 2009 Digital TV (DTV) Transition passed by Congress revolutionized television viewing in the United Stages – learn more about this historic transition and DTV by visiting www.DTV.gov.

 

Sours: http://www.freetvfresno.com/free-dtv/

Ever since the transition to digital television, most consumers have had more choices in free over-the-air broadcasting.  This guide provides information on TV antennas and tips for obtaining good quality reception of digital broadcasts.

Scanning for DTV Channels

Before making any changes to your current antenna or antenna system, you should perform a channel scan to see if your antenna receives the digital signals being broadcast in your area.

To run a channel scan, find the "set-up" or "menu" button on your remote control, then select the option that allows you to search for available digital broadcast channels. Once the scan is complete, you should be receiving all available digital channels in your area. In many cases, this is all you need to do to watch DTV broadcasts.

You should rescan periodically to ensure your TV has the current channel lineup for your area.

If you have any difficulty completing the channel scan, consult the owner's manual of your digital-to-analog converter box or DTV for detailed instructions. More information can be found at fcc.gov/rescan

Antennas for Receiving DTV

(Note: An auction of spectrum that had been licensed to broadcast television stations operating on UHF TV Channels 38-51 resulted in many TV stations on these channels transitioning to other channels. Almost all of the TV stations affected finished transitioning in July 2020.)

To receive DTV signals from all stations in the area, your antenna needs to be able to receive both VHF channels (channels 2-13) and UHF channels (channels 14-36). Some antennas only provide good reception of VHF or UHF channels, but not both. For example, indoor "rabbit ears" usually need to be augmented with an additional "wire loop" or "bowtie" antenna (see images in next tab) in order to pick up signals on UHF channels. Many of the antennas being sold as "HDTV Antennas" perform best at receiving UHF signals, but perform less well receiving VHF channels. Check with retail consultants and consumer websites to make sure that any antenna you choose provides good reception of both VHF and UHF channels.

Even if you use a digital-to-analog converter box, you will still need to use an antenna to receive DTV signals. Digital-to-analog converter boxes do not contain additional antennas or signal amplification.

Antennas for Different Conditions

The antennas shown below will work for the indicated signal strength in most instances, but may not work in all cases. The type of antenna needed at a specific location may vary depending on geographic location, the height at which the antenna is used and other local factors such as nearby buildings, trees, terrain or home construction. Generally, outdoor antennas will get better reception than indoor antennas and are strongly recommended for the most reliable reception.

Strong TV Signals

VHF

+

UHF

or

Combined VHF/UHF

Image of indoor VHF antennaImage of indoor UHF antennaImage of indoor VHF/UHF antenna

Simple indoor antennas may be sufficient for locations having strong TV signals.

Moderate TV Signals

High quality indoor antenna (check the box for information)
or an outdoor antenna may be appropriate.

Image of high quality indoor VHF/UHF antenna

Image of outdoor rooftop antenna

Weak TV Signals

Image of rooftop antenna

Outdoor antenna
is appropriate.

Image of outdoor rooftop antenna

See www.antennaweb.org for guidance on the type of outdoor antenna you may need.

Reception Tips

  • Antennas typically need to be oriented or "aimed" to get the best signal from the desired station. DTV reception can often be improved just by changing the location of your current antenna, even as little as a few inches. For example, moving it away from other objects or placing it higher or lower can often improve reception. Be sure to move the antenna slowly to allow time for the signal received by the digital TV tuner to be displayed. 
  • While adjusting your antenna, it may be helpful to access the "signal strength meter" on your digital-to-analog converter box or DTV, if it has one, to determine whether your adjustments are improving the signals' strength. The signal strength meter is usually accessed through the menu feature on your remote control; consult the owner's manual of your device for detailed instructions on how to access it.
  • Remember to do another channel scan after you have adjusted your antenna. For outdoor antennas, a rotor that re-orients the antenna can improve performance, particularly when trying to receive stations that transmit from different locations.
  • If you are near a station's broadcast tower, reception of that station, as well as other stations, can be impeded by strong signal "overload." If you suspect this to be the case, you may want to remove any signal amplifiers you may have or try to install an "attenuator" to reduce the amount of signal coming to your converter box or DTV.
  • If you are not receiving certain DTV stations, this does not necessarily mean there is a problem with your antenna or receiver. Check with the TV station to find out whether they are planning changes that will improve reception. To check available signals where you live, use the FCC's DTV reception maps.

Printable Version

Antennas and Digital Television (pdf)

Sours: https://www.fcc.gov/consumers/guides/antennas-and-digital-television
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The digital television (DTV) transition refers to the switch from analog to digital broadcast television. All full-power television stations have stopped broadcasting in analog, and now broadcast only in digital. Some consumers living along the U.S. borders with Mexico and Canada currently watch analog television programming broadcast over-the-air by Mexican and Canadian stations. Canadian TV stations will also transition from analog to digital broadcasting, but not until August of 2011. Mexico has begun its transition and will complete it in 2021.

U.S. consumers living along the Canadian and Mexican borders are able to watch television programming from Canadian or Mexican broadcast stations with an over-the-air antenna, such as “rabbit ears” on their set or an antenna on their roof.

If you purchase a digital-to-analog converter box to watch digital broadcasts on an analog TV and also wish to continue watching analog programming broadcast from stations in either Mexico or Canada, you should purchase a converter box with "analog pass-through" capability, which allows analog broadcast signals to pass through the converter box to be tuned by your analog TV. Converter boxes with analog pass-through capability will also enable you to watch U.S. low-power and translator television stations. (For more information on low-power and translator TV stations, see our Consumer Guide entitled “The DTV Transition and LPTV/Class A/Translator Stations”.)

Check with your retailer to determine whether the converter box you are purchasing has analog pass-through capability.

If you purchase a digital-to-analog converter box without analog pass-through capability, you may have to connect an “A/B switch” and/or a “signal splitter" to bypass the box if you wish to view analog TV broadcasts. Check with the manufacturer of the digital-to-analog converter box and your retailer if you need instructions on how to connect the box to view broadcasts from both analog and digital stations. For more information about the DTV transition, visit the FCC's DTV website.

Printable Version

DTV and Over-the-Air Viewers Along U.S. Borders (pdf)

Sours: https://www.fcc.gov/consumers/guides/dtv-and-over-air-viewers-along-us-borders
How is digital TV different from analog?

The terms "Digital Television" (DTV) and "High Definition Television" (HDTV) are often used interchangeably, but they are NOT the same thing.

Digital Television refers to a TV signal that is transmitted digitally as opposed to an analog signal. Digital Television can be broadcast in several different formats, as seen in the table below. Of these formats, two are considered to be "high definition". The term high definition implies that the resolution of the digital television signal is very high. For example, the 1080i standard is considered high definition and has a resolution approximately twice that of analog NTSC television.

There are 18 "standard" digital television formats. Each one provides a different picture quality. Digital TV formats are named using a number followed by either the letter 'p' or 'i'. Here are some of the more common formats:

FormatDescription
480iDigital version of current television signals.
480pAlso known as "standard definition" - has the same detail as today's television signal but looks sharper
720pThe HDTV format used by ABC and probably Fox. This format provides an image just about as good as 1080i, while allowing other 480p signals to be broadcast at the same time.
1080iThe most detailed image available from broadcast TV - the HDTV format used by NBC and CBS.

The number refers to the number of lines of vertical resolution . Generally the higher the number, the better the picture. For example A 720p image is much more detailed than a 480p image.

The letter refers to the way the TV makes the picture, either Progressive (p) or Interlaced (i).

A progressive scanmeans the TV draws line 1 of the image, then draws line 2, then line 3, then line 4, etc. until it reaches the bottom of the screen. Then it starts on the next image. This is what your computer monitor is doing right now.

An interlaced scanmeans the TV draws line 1 of the image, then draws line 3, then line 5, and every odd numbered line from there. Then it comes back and draws every even numbered line. This is the way regular TVs work.

You may have noticed that the image on your computer looks better than the image on your TV. With today's technology a progressive scan looks sharper than an interlaced scan. So a 480p image will look sharper than a 480i image.

Because a 'p' image looks sharper than an 'i' image, we can reduce the number of lines of resolution and still get a good-looking image. So a 720p image looks almost as good as a 1080i image.

Guide to Digital Television >>Back to the beginning >>

Sours: https://www.wave3.com/story/841687/what-is-the-difference-between-dtv-and-hdtv

Meaning dtv air

Digital television

television transmission using digital encoding

A map depicting digital terrestrial television standards

Digital television (DTV) is the transmission of television audiovisual signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s.[1] Modern digital television is transmitted in high definition (HDTV) with greater resolution than analog TV. It typically uses a widescreenaspect ratio (commonly 16:9) in contrast to the narrower format of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel,[2] and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:

  • Digital Video Broadcasting (DVB) uses coded orthogonal frequency-division multiplexing (OFDM) modulation and supports hierarchical transmission. This standard has been adopted in Europe, Africa, Asia, and Australia, for a total of approximately 60 countries.
  • Advanced Television System Committee (ATSC) uses eight-level vestigial sideband (8VSB) for terrestrial broadcasting. This standard has been adopted by 9 countries: the United States, Canada, Mexico, South Korea, Bahamas, Jamaica, the Dominican Republic, Haiti and Suriname.[citation needed]
  • Integrated Services Digital Broadcasting (ISDB) is a system designed to provide good reception to fixed receivers and also portable or mobile receivers. It utilizes OFDM and two-dimensional interleaving. It supports hierarchical transmission of up to three layers and uses MPEG-2 video and Advanced Audio Coding. This standard has been adopted in Japan and the Philippines. ISDB-T International is an adaptation of this standard using H.264/MPEG-4 AVC, which has been adopted in most of South America and Portuguese-speaking African countries.
  • Digital Terrestrial Multimedia Broadcasting (DTMB) adopts time-domain synchronous (TDS) OFDM technology with a pseudo-random signal frame to serve as the guard interval (GI) of the OFDM block and the training symbol. The DTMB standard has been adopted in China, including Hong Kong and Macau.[3]
  • Digital Multimedia Broadcasting (DMB) is a digital radio transmissiontechnology developed in South Korea[4][5][6] as part of the national IT project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems.

History[edit]

Background[edit]

Digital television's roots have been tied very closely to the availability of inexpensive, high performance computers. It was not until the 1990s that digital TV became a real possibility.[7] Digital television was previously not practically feasible due to the impractically high bandwidth requirements of uncompresseddigital video,[8][9] requiring around 200 Mbit/s (25 MB/s) for a standard-definition television (SDTV) signal,[8] and over 1 Gbit/s for high-definition television (HDTV).[9]

Digital TV became practically feasible in the early 1990s due to a major technological development, discrete cosine transform (DCT) video compression.[8][9] DCT coding is a lossy compression technique that was first proposed for image compression by Nasir Ahmed in 1972,[10] and was later adapted into a motion-compensated DCT video coding algorithm, for video coding standards such as the H.26x formats from 1988 onwards and the MPEG formats from 1991 onwards.[11][12] Motion-compensated DCT video compression significantly reduced the amount of bandwidth required for a digital TV signal.[8][9] DCT coding compressed down the bandwidth requirements of digital television signals to about 34 Mpps for SDTV and around 70–140 Mbit/s for HDTV while maintaining near-studio-quality transmission, making digital television a practical reality in the 1990s.[9]

Development[edit]

A digital TV service was proposed in 1986 by Nippon Telegraph and Telephone (NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an "Integrated Network System" service. However, it was not possible to practically implement such a digital TV service until the adoption of discrete cosine transform (DCT) video compression technology made it possible in the early 1990s.[8]

In the mid-1980s, as Japanese consumer electronics firms forged ahead with the development of HDTV technology, and as the MUSE analog format was proposed by Japan's public broadcaster NHK as a worldwide standard, Japanese advancements were seen as pacesetters that threatened to eclipse U.S. electronics companies. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner among the more than 23 different technical concepts under consideration.

Between 1988 and 1991, several European organizations were working on DCT-based digital video coding standards for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster RAI, developed a DCT video codec that broadcast SDTV at 34 Mbit/s and near-studio-quality HDTV at about 70–140 Mbit/s. RAI demonstrated this with a 1990 FIFA World Cup broadcast in March 1990.[9][13] An American company, General Instrument, also demonstrated the feasibility of a digital television signal in 1990. This led to the FCC being persuaded to delay its decision on an ATV standard until a digitally based standard could be developed.

In March 1990, when it became clear that a digital standard was feasible, the FCC made a number of critical decisions. First, the Commission declared that the new TV standard must be more than an enhanced analog signal, but be able to provide a genuine HDTV signal with at least twice the resolution of existing television images. Then, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being "simulcast" on different channels. The new ATV standard also allowed the new DTV signal to be based on entirely new design principles. Although incompatible with the existing NTSC standard, the new DTV standard would be able to incorporate many improvements.[7]

The final standard adopted by the FCC did not require a single standard for scanning formats, aspect ratios, or lines of resolution. This outcome resulted from a dispute between the consumer electronics industry (joined by some broadcasters) and the computer industry (joined by the film industry and some public interest groups) over which of the two scanning processes—interlaced or progressive—is superior. Interlaced scanning, which is used in televisions worldwide, scans even-numbered lines first, then odd-numbered ones. Progressive scanning, which is the format used in computers, scans lines in sequences, from top to bottom. The computer industry argued that progressive scanning is superior because it does not "flicker" in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet, and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offers a more efficient means of converting filmed programming into digital formats. For their part, the consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format.[7]

Inaugural launches[edit]

DirecTV in the U.S. launched the first commercial digital satellite platform in May 1994, using the Digital Satellite System (DSS) standard.[14][15]Digital cable broadcasts were tested and launched in the U.S. in 1996 by TCI and Time Warner.[16][17] The first digital terrestrial platform was launched in November 1998 as ONdigital in the United Kingdom, using the DVB-T standard.[18]

Technical information[edit]

Formats and bandwidth[edit]

Comparison of image quality between ISDB-T(1080i broadcast, top) and NTSC(480i transmission, bottom)

Digital television supports many different picture formats defined by the broadcast television systems which are a combination of size and aspect ratio (width to height ratio).

With digital terrestrial television (DTT) broadcasting, the range of formats can be broadly divided into two categories: high definition television (HDTV) for the transmission of high-definition video and standard-definition television (SDTV). These terms by themselves are not very precise, and many subtle intermediate cases exist.

One of several different HDTV formats that can be transmitted over DTV is: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlaced video mode (1080i). Each of these uses a 16:9 aspect ratio. HDTV cannot be transmitted over analog television channels because of channel capacity issues.

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. In terms of rectangular pixels, NTSC countries can deliver a 640 × 480 resolution in 4:3 and 854 × 480 in 16:9, while PAL can give 768 × 576 in 4:3 and 1024 × 576 in 16:9. However, broadcasters may choose to reduce these resolutions to reduce bit rate (e.g., many DVB-T channels in the United Kingdom use a horizontal resolution of 544 or 704 pixels per line).[19]

Each commercial broadcastingterrestrial television DTV channel in North America is permitted to be broadcast at a bit rate up to 19 megabits per second. However, the broadcaster does not need to use this entire bandwidth for just one broadcast channel. Instead the broadcast can use the channel to include PSIP and can also subdivide across several video subchannels (a.k.a. feeds) of varying quality and compression rates, including non-video datacasting services that allow one-way high-bit-rate streaming of data to computers like National Datacast.

A broadcaster may opt to use a standard-definition (SDTV) digital signal instead of an HDTV signal, because current convention allows the bandwidth of a DTV channel (or "multiplex") to be subdivided into multiple digital subchannels, (similar to what most FM radio stations offer with HD Radio), providing multiple feeds of entirely different television 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 bit rate and make reception easier for more distant or mobile viewers.

Receiving digital signal[edit]

There are several different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is from terrestrial transmitters 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 channels that have a terrestrial transmitter in range of their antenna.

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 Digital multimedia broadcasting (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 digital subscriber line (DSL) or optical cable line. Finally, an alternative way is to receive digital TV signals via the open Internet (Internet television), whether from a central streaming service or a P2P (peer-to-peer) system.

Some signals carry encryption and specify use conditions (such as "may not be recorded" or "may not be viewed on displays larger than 1 m in diagonal measure") backed up with the force of law under the World Intellectual Property Organization Copyright Treaty (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) for IS or named differently CableCard.

Protection parameters for terrestrial DTV broadcasting[edit]

Digital television signals must not interfere with each other, and they must also coexist with analog television until it is phased out. The following table gives allowable signal-to-noise and signal-to-interference ratios for various interference scenarios. This table is a crucial regulatory tool for controlling the placement and power levels of stations. Digital TV is more tolerant of interference than analog TV, and this is the reason a smaller range of channels can carry an all-digital set of television stations.[20]

System Parameters
(protection ratios)
Canada [13] USA [5] EBU [9, 12]
ITU-mode M3
Japan & Brazil [36, 37][21]
C/N for AWGN Channel +19.5 dB
(16.5 dB[22])
+15.19 dB +19.3 dB +19.2 dB
Co-Channel DTV into Analog TV +33.8 dB +34.44 dB +34 ~ 37 dB +38 dB
Co-Channel Analog TV into DTV +7.2 dB +1.81 dB +4 dB +4 dB
Co-Channel DTV into DTV +19.5 dB
(16.5 dB[22])
+15.27 dB +19 dB +19 dB
Lower Adjacent Channel DTV into Analog TV −16 dB −17.43 dB −5 ~ −11 dB[23]−6 dB
Upper Adjacent Channel DTV into Analog TV −12 dB −11.95 dB −1 ~ −10[23]−5 dB
Lower Adjacent Channel Analog TV into DTV −48 dB −47.33 dB −34 ~ −37 dB[23]−35 dB
Upper Adjacent Channel Analog TV into DTV −49 dB −48.71 dB −38 ~ −36 dB[23]−37 dB
Lower Adjacent Channel DTV into DTV −27 dB −28 dB −30 dB −28 dB
Upper Adjacent Channel DTV into DTV −27 dB −26 dB −30 dB −29 dB

Interaction[edit]

People can interact with a DTV system in various ways. One can, for example, browse the electronic program guide. Modern DTV systems sometimes use a return path providing feedback from the end user to the broadcaster. This is possible with a coaxial or fiber optic cable, a dialup modem, or Internet connection but is not possible with a standard antenna.

Some of these systems support video on demand using a communication channel localized to a neighborhood rather than a city (terrestrial) or an even larger area (satellite).

1-segment broadcasting[edit]

Main article: 1seg

1seg (1-segment) is a special form of ISDB. Each channel is further divided into 13 segments. The 12 segments of them are allocated for HDTV and remaining segment, the 13th, is used for narrow-band receivers such as mobile television or cell phone.

Timeline of transition[edit]

Further information: Digital television transition

Comparison of analog vs digital[edit]

See also: Analog television

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 reduction in image quality depending on the level of compression as well as the resolution of the transmitted image. 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 and analog signals react to interference differently. For example, common problems with analog television include ghosting of images, noise from weak signals, and many other potential problems which degrade the quality of the image and sound, although the program material may still be watchable. With digital television, the audio and video must be synchronized digitally, so reception of the digital signal must be very nearly complete; otherwise, neither audio nor video will be usable. Short of this complete failure, "blocky" video is seen when the digital signal experiences interference.

Analog TV began with monophonic sound, and later developed multichannel television sound with two independent audio signal channels. DTV allows up to 5 audio signal channels plus a subwoofer bass channel, with broadcasts similar in quality to movie theaters and DVDs.[24]

Digital TV signals require less transmission power than analog TV signals to be broadcast and received satisfactorily.[25]

Compression artifacts, picture quality monitoring, and allocated bandwidth[edit]

DTV images have some picture defects that are not present on analog television or motion picture cinema, because of present-day limitations of bit rate and compression algorithms such as MPEG-2. This defect is sometimes referred to as "mosquito noise".[26]

Because of the way the human visual system works, defects in an image that are localized to particular features of the image or that come and go are more perceptible than defects that are uniform and constant. However, the DTV system is designed to take advantage of other limitations of the human visual system to help mask these flaws, e.g. by allowing more compression artifacts during fast motion where the eye cannot track and resolve them as easily and, conversely, minimizing artifacts in still backgrounds that may be closely examined in a scene (since time allows).

Broadcast, cable, satellite, and Internet DTV operators control the picture quality of television signal encodes using sophisticated, neuroscience-based algorithms, such as the structural similarity (SSIM) video quality measurement tool, which was accorded each of its inventors a Primetime Emmy because of its global use. Another tool, called Visual Information Fidelity (VIF), is a top-performing algorithm at the core of the NetflixVMAF video quality monitoring system, which accounts for about 35% of all U.S. bandwidth consumption.

Effects of poor reception[edit]

Changes in signal reception from factors such as degrading antenna connections or changing weather conditions may gradually reduce the quality of analog TV. The nature of digital TV results in a perfectly decodable video initially, until the receiving equipment starts picking up interference that overpowers the desired signal or if the signal is too weak to decode. Some equipment will show a garbled picture with significant damage, while other devices may go directly from perfectly decodable video to no video at all or lock up. This phenomenon is known as the digital cliff effect.

Block error may occur when transmission is done with compressed images. A block error in a single frame often results in black boxes in several subsequent frames, making viewing difficult.

For remote locations, distant channels that, as analog signals, were previously usable in a snowy and degraded state may, as digital signals, be perfectly decodable or may become completely unavailable. The use of higher frequencies will add to these problems, especially in cases where a clear line-of-sight from the receiving antenna to the transmitter is not available, because usually higher frequency signals can't pass through obstacles as easily.

Effect on old analog technology[edit]

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This section needs to be updated. Please help update this article to reflect recent events or newly available information.(February 2017)

Television sets with only analog tuners cannot decode digital transmissions. When analog broadcasting over the air ceases, users of sets with analog-only tuners may use other sources of programming (e.g. cable, recorded media) or may purchase set-top converter boxes to tune in the digital signals. In the United States, a government-sponsored coupon was available to offset the cost of an external converter box. Analog switch-off (of full-power stations) took place on December 11, 2006 in The Netherlands,[27] June 12, 2009 in the United States for full-power stations, and later for Class-A Stations on September 1, 2016,[28] July 24, 2011 in Japan,[29] August 31, 2011 in Canada,[30] February 13, 2012 in Arab states, May 1, 2012 in Germany, October 24, 2012 in the United Kingdom[31] and Ireland,[32] October 31, 2012 in selected Indian cities,[33] and December 10, 2013 in Australia.[34] Completion of analog switch-off is scheduled for December 31, 2017 in the whole of India,[33] December 2018 in Costa Rica and around 2020 for the Philippines.

Disappearance of TV-audio receivers[edit]

Prior to the conversion to digital TV, analog television broadcast audio for TV channels on a separate FM carrier signal from the video signal. This FM audio signal could be heard using standard radios equipped with the appropriate tuning circuits.

However, after the transition of many countries to digital TV, no portable radio manufacturer has yet developed an alternative method for portable radios to play just the audio signal of digital TV channels; DTV radio is not the same thing.

Environmental issues[edit]

The adoption of a broadcast standard incompatible with existing analog receivers has created the problem of large numbers of analog receivers being discarded during digital television transition. One superintendent of public works was quoted in 2009 saying; "some of the studies I’ve read in the trade magazines say up to a quarter of American households could be throwing a TV out in the next two years following the regulation change".[35] In 2009, an estimated 99 million analog TV receivers were sitting unused in homes in the US alone and, while some obsolete receivers are being retrofitted with converters, many more are simply dumped in landfills where they represent a source of toxic metals such as lead as well as lesser amounts of materials such as barium, cadmium and chromium.[36][37]

According to one campaign group, a CRTcomputer monitor or TV contains an average of 8 pounds (3.6 kg) of lead.[38] According to another source, the lead in glass of a CRT varies from 1.08 lb to 11.28 lb, depending on screen size and type, but the lead is in the form of "stable and immobile" lead oxide mixed into the glass.[39] It is claimed that the lead can have long-term negative effects on the environment if dumped as landfill.[40] However, the glass envelope can be recycled at suitably equipped facilities.[41] Other portions of the receiver may be subject to disposal as hazardous material.

Local restrictions on disposal of these materials vary widely; in some cases second-hand stores have refused to accept working color television receivers for resale due to the increasing costs of disposing of unsold TVs. Those thrift stores which are still accepting donated TVs have reported significant increases in good-condition working used television receivers abandoned by viewers who often expect them not to work after digital transition.[42]

In Michigan in 2009, one recycler estimated that as many as one household in four would dispose of or recycle a TV set in the following year.[43] The digital television transition, migration to high-definition television receivers and the replacement of CRTs with flatscreens are all factors in the increasing number of discarded analog CRT-based television receivers.

See also[edit]

Notes and references[edit]

  1. ^Kruger, Lennard G. (2002). Digital Television: An Overview. New York: Nova Publishers. ISBN .
  2. ^"HDTV Set Top Boxes and Digital TV Broadcast Information". Archived from the original on 22 May 2016. Retrieved 28 June 2014.
  3. ^Ong, C. Y., Song, J., Pan, C., & Li, Y.(2010, May). Technology and Standards of Digital Television Terrestrial Multimedia Broadcasting [Topics in Wireless Communications], IEEE Communications Magazine, 48(5),119-127
  4. ^"Korea's Terrestrial DMB: Germany to begin broadcast this May". ZDNet Korea. 2006-04-06. Retrieved 2010-06-17.
  5. ^"picturephoning.com: DMB". Textually.org. Archived from the original on 2010-08-09. Retrieved 2010-06-17.
  6. ^"South Korea : Social Media 답변 내용 : 악어새 - 리포트월드". Reportworld.co.kr. Archived from the original on 2009-08-17. Retrieved 2010-06-17.
  7. ^ abc"The Origins and Future Prospects of Digital Television". Benton Foundation. 2008-12-23.
  8. ^ abcdeLea, William (1994). Video on demand: Research Paper 94/68. 9 May 1994: House of Commons Library. Retrieved 20 September 2019.CS1 maint: location (link)
  9. ^ abcdefBarbero, M.; Hofmann, H.; Wells, N. D. (14 November 1991). "DCT source coding and current implementations for HDTV". EBU Technical Review. European Broadcasting Union (251): 22–33. Retrieved 4 November 2019.
  10. ^Ahmed, Nasir (January 1991). "How I Came Up With the Discrete Cosine Transform". Digital Signal Processing. 1 (1): 4–5. doi:10.1016/1051-2004(91)90086-Z.
  11. ^Ghanbari, Mohammed (2003). Standard Codecs: Image Compression to Advanced Video Coding. Institution of Engineering and Technology. pp. 1–2. ISBN .
  12. ^Li, Jian Ping (2006). Proceedings of the International Computer Conference 2006 on Wavelet Active Media Technology and Information Processing: Chongqing, China, 29-31 August 2006. World Scientific. p. 847. ISBN .
  13. ^Barbero, M.; Stroppiana, M. (October 1992). "Data compression for HDTV transmission and distribution". IEE Colloquium on Applications of Video Compression in Broadcasting: 10/1–10/5.
  14. ^"History of U.S. Satellite Broadcasting Company, Inc. – FundingUniverse". www.fundinguniverse.com. Retrieved 9 August 2018.
  15. ^"Business Insider: Digital satellite TV has Indy roots". Retrieved 9 August 2018.
  16. ^"NextLevel signs cable deal - Dec. 17, 1997". money.cnn.com. Retrieved 9 August 2018.
  17. ^"TCI faces big challenges - Aug. 15, 1996". money.cnn.com. Retrieved 9 August 2018.
  18. ^"CANAL+ TECHNOLOGIES and the world's first digital terrestrial television service in the United Kingdom". Retrieved 9 August 2018.
  19. ^Latest snapshots - Freeview/DTT bitratesArchived 2007-11-22 at the Wayback Machine (Mendip transmitter, UK)
  20. ^"Frequently Asked Questions -- What Is Digital TV?". ABC News. Retrieved 2020-09-30.
  21. ^ISDB-T (6 MHz, 64QAM, R=2/3), Analog TV (M/NTSC).
  22. ^ abThe Canadian parameter, C/(N+I) of noise plus co-channel DTV interface should be 16.5 dB.
  23. ^ abcdDepending on analog TV systems used.
  24. ^"Digital TV: A Cringley Crash Course — Digital Vs. Analog". Pbs.org. Retrieved 2014-01-13.
  25. ^https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2140-3-2011-PDF-E.pdf
  26. ^Le Dinh, Phuc-Tue; Patry, Jacques (February 24, 2006). "Video compression artifacts and MPEG noise reduction". Video Imaging DesignLine. Retrieved April 30, 2010.
  27. ^"How Television went Digital in The Netherlands"(PDF). Open Society Foundations September 2011. Archived from the original(PDF) on 2013-04-20. Retrieved 2013-02-04.
  28. ^"The Digital TV Transition: Will You Be Affected?". FCC. Retrieved 2009-11-02.
  29. ^"New DTV Hard Date: July 24, 2011?". B&C. Retrieved 2009-11-02. - dead link
  30. ^"DTV Post-Transition Allotment Plan"(PDF). Spectrum Management and Telecommunications. Retrieved 2009-11-02.
  31. ^"End of analogue TV era as switchover completes in the UK"(PDF). Digital UK. Retrieved 2012-12-21.
  32. ^"Analogue switch off has finally happened". SAORVIEW. Retrieved 2012-12-21.
  33. ^ ab"Find out when digital switch over is coming to you". Government of India Ministry of Information & Broadcasting. Retrieved 2012-12-21.
  34. ^"Australia's ready for digital TV". Digital Ready AU. Archived from the original on 2013-01-29. Retrieved 2013-12-25.
  35. ^North Tonawanda: council discusses future TV disposalArchived 2009-01-31 at the Wayback Machine, Neale Gulley, Tonawanda News, January 27, 2009
  36. ^Old Toxic TVs Cause Problems, USA TODAY, January 27, 2009
  37. ^Unloading that old TV not quite so simple, Lee Bergquist, Milwaukee Journal-Sentinel, January 23, 2009
  38. ^Campaigners highlight 'toxic TVs', Maggie Shiels, BBC News, 9 January 2009
  39. ^"Lead in Cathode Ray Tubes (CRTs) Information Sheet**"(PDF). Electronic Industries Alliance. 2001-11-30. p. 1. Archived from the original(PDF) on 2011-05-20. Retrieved 2009-09-29.
  40. ^Poon, C.S. (2008). "Management of CRT glass from discarded computer monitors and TV sets". Waste Management. 28 (9): 1499. doi:10.1016/j.wasman.2008.06.001. hdl:10397/24493. PMID 18571917. Retrieved 2009-09-29.
  41. ^What To Do With Your Old TV's, Mike Webster, WCSH-TV, January 28, 2009 - dead link
  42. ^Many people throwing out perfectly good TVs over digital confusionArchived 2009-01-23 at the Wayback Machine, Daniel Vasquez, Sun-Sentinel, Florida, January 19, 2009
  43. ^Trashing the tube: Digital conversion may spark glut of toxic waste, Jennifer Chambers, Detroit News, January 23, 2009

Further reading[edit]

External links[edit]

Sours: https://en.wikipedia.org/wiki/Digital_television
How to fit a TV Connector Plug onto a Coaxial AERIAL Cable

Digital TV antennas have come a long ways since your grandma’s rabbit ears antennas you grew up with. Here is our list of the 10 things you need to know about modern day digital TV antennas.

  1. Broadcast signals are superior to cable and satellite.

There are no paid subscription fees to receive over-the-air (OTA) television, and the picture and sound quality is far superior. In addition, OTA broadcasts are free from the signal compressions used by cable and satellite giving you unadulterated high definition television.

  1. Unlock new local channels.

Cable and Satellite providers do not carry all the channels that may be available in your area. In fact, most broadcast stations offer additional regional programming, absolutely free. These channels include local news, sports, cooking shows, kids programming along with classic TV shows and movies.

  1. All the major networks transmit signals free over-the-air.

You don’t have to pay for some of the content you receive on cable or satellite. The broadcast networks are paid for by advertisers, not subscribers. All your local news, weather, sitcoms, cooking shows, kid’s shows, sports and thousands of movies are available free with an antenna.

  1. ‘HD’ or ‘HDTV’ antennas are some of the more common names used for digital TV antennas.

All digital antennas receive the same picture and sound quality; we just give them a familiar name. Some broadcasts will be in full HD while others are broadcast in standard definition. The real difference is the uncompressed signal received with an antenna.

  1. There are channels, and then there are sub-channels.

Each broadcast station sends out a signal on a frequency (channel). This frequency will provide many ‘sub-channels’ containing your programming. For example, a channel broadcast on channel 8, would appear on your TV as sub-channel group 8.1, 8.2, 8.3 etc. Each channel, aside from its main service can be broadcasting additional programming on 1 to 4 sub-channels simultaneously.

  1. Antennas are a great compliment to any cable or satellite subscription.

Complimenting your television setup with a digital antenna will come in handy the next time your cable or satellite blacks out. During emergencies or bad weather, receiving OTA signals to your TV with an antenna will keep you informed. Much like a radio, the frequency is more reliable and less subject to interruption.

  1. Find the broadcast towers before you choose an antenna.

When choosing an antenna, remember that every set up is unique to the location in which you live. Click HERE to learn more about antenna selection.

  1. Hills, trees, and buildings bend, deflect, and weaken signals.

The digital TV signal is a ‘line of sight’ signal. Typically, the higher you have your antenna, the better the reception. While signals pass through walls and other surfaces, the more obstructions the signal encounters, the weaker the signal and this causes signal disruption. The clearest, most unobstructed view to the broadcast towers will allow the antenna to perform at the highest level.

  1. 3 things you need to receive over-the-air digital broadcast TV
  • A television with a digital tuner (found in any TV manufactured after March 2007)
  • The right antenna for your specific location. See here at Antenna Point
  • The knowledge of broadcast tower locations in your area. Point your antenna toward them and bask in the glory of OTA, free television.

10. There is no magic antenna.

Antennas come in a variety of shapes and sizes, each designed for a specific situation. Some are narrow focused (directional) antennas; while others are multidirectional both with various range capacities. Well-designed antennas, such as our patented Tapered Loop, are tuned for specific frequency ranges and geographical challenges, which will increase your chances for success.

There is no ‘one-size-fits-all’ solution in an antenna. To help you choose the right antenna, view our Antenna Selection Page or Live Chat with an expert now.

HERE ARE SOME TIPS FOR SUCCESS:

  • Outdoor installation is best, but Antennas Direct antennas can also be installed indoors or in attics. (50% strength/range is lost indoors).
  • Simple, direct connections and installations are best. The more junctions in the installation, the higher the signal loss.
  • Each time the signal is split (to go to another TV) signal strength is reduced, so a low-noise amplifier may be needed to help compensate for the signal reduction.
  • Install the antenna where signal is “present”. Move the antenna to different locations until signals are found. Many times one end of the roof or room has better signal characteristics than the others.

Read Next: A Cord Cutter Tells All: 6 Steps to TV Freedom

Sours: https://www.antennasdirect.com/blog/10-digital-tv-antennas/

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