Digital TV or DTV

It was the year 1940 when television standards of NTSC - National Television Systems Committee, were approved by FCC - federal communications commissions. These TVs were still in use with lots of improvements but with the same old ways of transmitting analogue signals, till the Digital Televisions came in action. The old analogue TV receives only analogue signals, which have lots of drawbacks in them. Basically an analogue transmission means transmission of video and audio. In case of Digital TV its quite different world with a digital camera having far more high resolution than analogue, purely digital transmission and truly digital image display with very high resolution.

Digital TV Transmission

In case of analogue transmission, video and audio are transmitted by separate signals. The VDO signal consist of rows of dots called pixels each having its own color and intensity, synchronized with sync signals so that electronics of TV inside understands them. For transmission purposes 6MHz slot is available for the broadcasters. These analogue signals can suffer from lots of reason like bad weather (snowing, raining), how your antenna receives them causing double images cross channel interference and lots more depending upon your residence. When it comes to digital TV transmission its like what happens in CDs the data is stored as ones and zeroes that is the information is digitized and unlinked to the orbital satellites which transmits them to the dish at the roof top that transfers the digital data at your Digital TV set. The digital data is quite less affected by the surrounding conditions and so the chances of interference are quit low.

Digital TV Display

The main reason TV industry moved towards Digital TV was resolution of display. The analogue TV set has a resolution of 512 * 400 pixels where as a lowest resolution monitor is 540 * 480 pixels providing more crisp and sharp picture. So this was monitor who made the people to think about a TV set with high resolution and they came up with the digital television.

Digital TV can be categorized into three standards:

1. HD TV 1080 with 1080 lines of resolution and 16:9 aspect ratio
2. HD TV 720 with 720 lines of resolution and 16:9 aspect ratio
3. SD TV with 480 lines of resolution and 16:9 or 4:3 aspect ratio

HDTV stands for high definition television and SDTV standard definition television.

 

Broadcasting

The broadcasters in USA have now a new frequency for their digital broadcasts allotted to them by FCC. So each broadcaster has one analogue TV channel and one digital TV channel for the broadcasting. One digital channel can carry a 19.39 - Mbps (mega bit per second) stream of digital data, which your digital TV receives and sends it to your Digital TV receiver to decode it. One digital channel can be further divided into sub channels like one channel of 19.39 Mbps can be divided into 3 sub-channels of 6.46 Mbps carrying three 6.46 Mbps stream of digital data. Each sub-channel can carry different programming. The channel division is possible because of several Digital TV formats availability.

Formats

480i & 480p with 704x480 resolution
1080i & 1080p with 1920x1080 resolution
720p with 1280x720 resolution

• The difference comes B/W “p” and “i” “p” stands for progressive format in which the full picture is updated every sixtieth of a second .
• “i” stands for interlaced format in which half the picture is updated every sixtieth of a second.
• The broadcasters have a choice to use any three of them.480i and 480p are for SDTV where as 720p, 1080i and 1080p are for HD TV broadcasting.

 

Digital TV Programming

To provide 100% pure digital programming there are sophisticate centers in USA and DBS Satellite TV services. Dish network and Direct TV are the two largest DBS services providing special DVR and HDTV packages and equipments along with high standards of programming packages.

Conclusion

On the whole for all the TV lovers who believe in quality entertainment or information, Digital TV is there for them with the high quality and resolution of picture along with high standards of programming.