Digital television in the United States

See digital television for more technical details, or DTV transition in the United States for specific information related to the analog-to-digital switchover

In the United States, digital television broadcasts, or DTV, can be received via cable, via internet, via satellite, or via free over-the-air (OTA) digital terrestrial television - much like analog television broadcasts have been. Full-power analog television broadcasts, however, were required by U.S. federal law to cease by June 12, 2009. Low-power, Class A, and TV Translator stations are not currently required to cease analog broadcasts. Also by law, digital broadcasts - when transmitted as OTA signals - must conform to ATSC standards.;[1] it is unclear whether satellite operators are free to use their own proprietary standards; and many standards exist for internet television (most are proprietary).

Standards

The U.S. opted to adhere to ATSC standards for broadcast digital television. These standards define, among other things, format and transmission criteria that ensure consistency, accessibility, and fairness for consumers and equipment manufacturers alike in the U.S., as well as international compatibility.

Format standards

The five main ATSC formats of DTV currently broadcast in the U.S. are:

Most digital television sets sold in the U.S. use a display with a 16:9 aspect ratio to optimally display HDTV-formatted content. Lower-resolution sources like regular DVDs may be upscaled to the native resolution of the TV.

Transmission standards

Cable and satellite

Currently, most Americans get digital television broadcasts via cable or satellite. Digital cable television systems with an activated channel capacity of 750 MHz or greater, are required by the FCC to follow ANSI/SCTE transmission standards with the exception of cable systems that only pass through 8 VSB modulated signals.[2] Digital television sets (equipped with ATSC tuners) are often capable of viewing a baseline set of unencrypted digital programming, known as basic cable, which typically include local network television affiliates. According to FCC regulations, the remaining encrypted channels must be viewable with a receiver equipped with a CableCARD,.

Terrestrial

Digital television transmissions over-the-air (OTA) are now available in most metropolitan areas in the U.S., often carrying both standard-definition and high-definition (HDTV) transmissions of the same stations.[3] In fact, by the analog shut-off date of June 12, 2009, all Full Power OTA stations in the U.S. will, by law, have to either transmit their broadcasts digitally, or shut down.

Many stations have already used the switch to digital transmission as an opportunity to transition from 480i broadcasts to digital HD OTA broadcasts (either in 720p or 1080i), though this change is voluntary.

Within a distance of 35 to 40 miles from the broadcast stations, it is possible that no equipment more special than perhaps a simple antenna (such as "rabbit ears") may be necessary to receive a DTV broadcast signal OTA—at least some of the time for some of the channels. Any television equipped with an ATSC tuner may display DTV broadcasts properly. Some customers are already discovering that terrain, trees, rain, snow, wind, and even the movement of people around the room interfere with reception to one degree or another, from signals breaking up to total loss of signal. (Few ATSC-equipped televisions or converter boxes have internal antennas, in contrast to analog sets available in years past).

Transition from analog to digital OTA broadcasts in 2009

It is estimated that as of April 2007, 28% of American households had an HDTV set, a total of 35 million sets, and that 86% of owners were highly satisfied with the HDTV programming[4] Estimates are that by the end of 2010, some 59% of American TVs had transitioned to HDTVs. All TV stations currently broadcast in both digital and analog and major networks broadcast in HD in most markets.

While many in the industry wanted a flexible or delayed deadline, the FCC forced the issue at the behest of Congress. Congress wanted to reclaim some of the spectrum used for analog and repurpose that for emergency services. They also wanted to auction off bandwidth between 76-88 MHz frequencies (channels 5 and 6)and old analog UHF channels 60 to 69, and channels 52 to 59 by mandating DTV tuners be phased into all new TV sets. Many transition dates were proposed, but Congress finally fixed February 17, 2009 (later extending it until June 12, 2009), in law as the maximum end date for analog television authorizations.[5] Because this date comes after the NCAA's Bowl Championship Series and the NFL's Super Bowl XLIII, there will be less of a chance of an acute hardware shortage from people waiting until the last minute to purchase an ATSC tuner than there would have been with a January 1 cutoff. The original deadline of January 1, 2006 was abolished when it was realized that TV stations and customers would not be able to meet the earlier deadline.

In March 2008, the FCC requested public comment on turning the bandwidth currently occupied by analog television channels 5 and 6 (76–88 MHz) over to extending the FM broadcast band when the digital television transition was to be completed in February 2009 (ultimately delayed to June 2009).[6] This proposed allocation would effectively assign frequencies corresponding to the existing Japanese FM radio service (which begins at 76 MHz) for use as an extension to the existing North American FM broadcast band.[7]

Ultimately, VHF Channels 5 and 6 were retained for digital broadcast television use after the transition, though the FCC had continued researching the possibility of re-allocating the two channels to an expanded FM band.

Wikipedia Entry -Digital Television in the USA

The Origins of Digital TV

Digital television began in Japan with their development of high definition television (or HDTV) in the 1980’s. The development improved picture quality on TV. Japan first initiated HDTV broadcasts in 1992. However, the United States government wanted greatly to create their own American made HGTV broadcast technology. In fact, US manufacturers felt that is was imperative not to be reliant on Japan to supply the US with new HDTV broadcasts technologies, so US manufacturers stepped it up. In the book, Digital Cultures: Understanding New Media, the USA’s adoption of digital television, is described as the following: “With new digital technology-homegrown in Silicon Valley a much higher definition television picture could be produced, as good as or better than the Japanese MUSE technology that had started the whole thing off. By 1993, US manufacturers had come up with a strategic Grand Alliance standard, representing a technical compromise between the competing needs of different industry segments that could handle a variety of digital high-definition formats with varying degrees of resolution, pixel density, frame rates and scanning methods.” (Creeber and Martin :2009) The US Telecommunications Act of 1999 held a special place in the introduction of digital television into the United States. This act allowed for regional phone companies, long-distance phone carriers, and cable companies to enter each other’s markets. The Telecommunications Act enabled cable companies to offer triple play packages (also known as bundle packages). These packages often now include digital television, broadband internet, and telephone services.

The Benefits of Digital TV over Analog TV

It is often written that digital television is better, than analogue television. But what makes a digital signal better than and analog signal? And how has the induction of digital television benefited individual television consumers in contrast to analogue television? A digital signal translates television images and sounds into a binary code of ones and zeros. An analog signal has defined levels of voltage. Digital television (or DTV) has many advantages over analog television. Some of these advantages include better image quality and high resolution. DTV signals require much less frequency space. This in turn makes the picture quality on a bigger newer flat screen TV better. In contrast, an analog signal is continuously variable (or continuously changing) as the voltage values move about in time. This is why older analog TV sets could not decode and display digital signals unless they are switched over to digital. In June 2009, the Federal Commerce Commission (or FCC) initiated the switch from analog TV to digital TV. This made older analog TV’s unusable for new digital cable and satellite broadcast. The exception came was when some consumers brought digital converter boxes for their older TV sets or brought new flat screen TV’s. In fact, in Media and Culture: An Introduction to Mass Communication it states: “To ensure that uninterrupted to free, over-the-air television did not pose a financial hardship for viewers, in January 2008 the government began issuing $40 gift cards (up to two per household) to consumers who needed to purchase digital converters…Although the government spent $2 billion on ads and gift cards to help with the conversion, about nine million households (out of fourteen million) were not ready and saw their TVs go blank.” (Campbell, Martin, & Fabos: 2011)


Digital TV Broadcast Distribution Methods

There are two main ways that digital television broadcast are usually distributed to people’s homes in the United States. The first is by using a digital cable provider such as Time Warner or Comcast. The second is by using a satellite dish provider such as DIRECTV or Echo Star’s Dish TV. Digital Cable works by a headend (or computerized nerve center) receiving long-distance signals to pick up local, independent, and national broadcast stations through a satellite dish attached to a fiber optic cable. These signals are then feed through trunk and feeder cables attached to utility poles. Cable companies rent space on these poles from phone and electric companies. Drop lines are then run the cable to subscribers’ homes on utility poles and digital cable consumers receive their digital TV using a cable converter box. Just as with digital cable satellite dish cable works by beaming a signal from a ground station up to a satellite in orbit. This satellite is geosynchronous, meaning it rotates at the same speed the earth rotates on its axis. In Digital Cultures: Understanding New Media it states: “Satellite television works by beaming signals from a ground station up to a satellite in geostationary orbit, 2,300 miles above the earth’s surface…. [The satellite signals are] just at the right point in the earth’s gravitational pull to rotate at the same speed as the earth, keeping them [the satellite’s signals] in a fixed position relative to points on the ground. (Creeber & Martin: 2009) The difference however lies in the dish. When you receive “dish cable” through a provider (such as DIRECTV or Dish TV) each cable consumer receives their own individual dish which is tested for signal strength during the time of installation.

“Signals are relayed by the satellite transponders operating in the KU band of frequencies back down to earth, where they are received by satellite dishes, placed either on individual roofs or balconies, or in a satellite array set up by companies who retransmit their signals in another form (like cable or broadcast).” (Creeber & Martin: 2009)


The Best Features of Digital TV

There are three main features that American consumers can gain from having digital television (or DTV). Those three features are as follows: Digital Video Recorder (DVR), on demand, and increased network channels. The Digital Video Recorder (or as it’s commonly known as DVR) feature allows American DTV consumers to watch their favorite broadcast shows whenever they desire by placing by recording them for future viewing purposes. On Demand allows consumers to instantly watch different shows from different networks and movies using the “On Demand” button. For example, digital cable provider Time Warner Cable allows cable viewers to watch new American Idol episodes and new movies like Addicted. Additionally, satellite dish providers such as DIRECTV allow digital cable viewers to receive international channels. All digital television providers now offer more channels for their consumers nowadays. This is partially, due to the fact that TV stations can assign more channels to the same frequency and because of the satellites linking the nation (and the world) through digital television. Media & Culture: An Introduction to Mass Communication authors wrote: “…there are other pluses to going digital. Because digital signals require less frequency space than analog signals, TV stations can compress a digital signal and carry several different signals using the same frequency or bandwidth.” (Campbell, Martin, & Fabos: 2011)

References Creeber, G. & Martin, R. (Eds.). (2009) Digital Cultures: Understanding new media. New York, NY: Ashford Colour Press Ltd., Gosport, Hants. Campbell, R., Martin, C. R. & Fabos, B. (Eds.). (2011) Media & Culture: An introduction to mass communication. Boston, MA: Bedford/ St. Martin’s.



On August 22, 2011, the United States' Federal Communications Commission announced a freeze on all future applications for broadcast stations requesting to use channel 51,[8] to prevent adjacent-channel interference to the A-Block of the 700 MHz band. Later that year (on December 16, 2011), Industry Canada and the CRTC followed suit in placing a moratorium on future television stations using Channel 51 for broadcast use, to prevent adjacent-channel interference to the A-Block of the 700 MHz band.[9]

Early rollout of transition

On May 8, 2008, FCC Chairman Kevin J. Martin announced the agency would test run the transition to digital television in Wilmington, North Carolina, beginning September 8, 2008. This test run was to work out problems that might have occurred before the complete transition.

See also

References

  1. ↑ FCC. The Digital TV Transition FAQs
  2. ↑ "76.640 Support for unidirectional digital cable products on digital cable systems.". Government Printing Office. 8 Nov 2003.
  3. ↑ http://antennaweb.org/ AntennaWeb
  4. ↑ WKYC's Director's Cut with Frank Macek: News: HDTV Penetration at 28%
  5. ↑ 47 USC 309(j)(14)(A) as amended by section 3002 of S.1932 signed into law February 8, 2006
  6. ↑ Federal Communications Commission (2008-05-16). "In the Matter of Promoting Diversification of Ownership in the Broadcasting Services". Retrieved 2008-08-26. Certain commenters have urged the Commission to give a "hard look" to a proposal that the Commission re-allocate TV Channels 5 and 6 for FM broadcasting 73 FR 28400, 28403
  7. ↑ Could EXB Band Be Your New Home?RadioWorld September 10, 2008
  8. ↑ FCCPublic Notice DA-11-1428A1:
  9. ↑ Industry Canada Advisory Letter - Moratorium on the Use of Television Channel 51

External links