Digital Television (DTV) is the sending and receiving of moving images and sound by discrete (digital) signals, in contrast to the analog signals used by analog TV.
The first country to make a wholesale switch to Digital Over-the-Air (terrestrial) broadcasting was the Netherlands, in 2006. This was followed by Finland and Sweden in 2007.
In the United States, full-power television stations are scheduled to change over to digital on June 12, 2009. By special dispensation, some analog TV signals will cease, as previously scheduled, on February 17, 2009. This has to do with station resistance to a sudden change in schedule, that will cost broadcasters money and cause logistical nightmares.
In Japan, the switch to digital is scheduled to happen July 24, 2011. In Canada, it is scheduled to happen August 31, 2011. China is scheduled to switch in 2015. In the United Kingdom, the digital switchover has different times for each part of the country; however, the whole of the UK will be digital by 2012. Brazil switched to digital in December 2, 2007 in major cities and it is estimated 7 years for complete signal expansion over all of the Brazilian territory.
There are a number of different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is using an antenna (known as an aerial in some countries). This way is known as Digital Terrestrial Television (DTT). With DTT, viewers are limited to whatever channels the antenna picks up. Signal quality will also vary.
Other ways have been devised to receive digital television. Among the most familiar to people are digital cable and digital satellite. Another way is IPTV, that is receiving TV via Internet Protocol, relying on DSL or optical cable line. Finally, an alternative way is to receive digital TV signals via the open Internet. For example, there is a lot of P2P Internet Television software that can be used to watch TV on your computer. There are other standards for digital TV too.
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”.
Direct To Home (DTH) Satellite TV service that promises to redefine the digital home entertainment experience in 62 cities across India started in October 9, 2008. Indian digital TV uses the latest MPEG4 standard with DVB S2 technology for exceptional picture clarity and high quality audio, and high definition ready interactive content. They also claim a 20% larger dish antenna ensures better performance during rain.
Brigadier(Retired) Sukhwindar Singh
Credit: Wikipedia & Internet Research.
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