Concept of DTV---Are digital TV pictures better?

cctv.com 11-17-2004 14:10

Analogue TV pictures received through an aerial can suffer snow, ghosting, cross-channel interference and other effects, depending on where you live and how your aerial is installed. Digital pictures are different, they degrade much more quickly. This means you are likely to see either a perfect picture or no picture at all.

Sky are claiming that Digital pictures do not suffer from interference caused by weather conditions. This appears contrary to the experiences people are having. Although digital pictures are much more robust than their analogue counterparts, they can suffer from corruption.

Indeed, digital pictures are not perfect. They suffer from symptoms linked to the limitations of compression technology. If the content of the picture changes too quickly, you begin to see "blocks" in the pictures that shouldn't be there. (These are called "Digital Artefacts"). This can also happen if the pictures from other channels are fighting for the same bandwidth.

Many viewers visiting Live 98, the consumer electronics show in London, have reported how the demonstrations of digital TV show poor pictures. I have also seen remarkably poor pictures from BBC Choice on the launch day of SkyDigital, with similar results reported for other channels such as THE BOX.

It's important to remember that digital television is not high definition television. Digital pictures occupy the same 625 lines as analogue pictures. This contrasts with digital television in other countries such as the USA where high definition pictures were due before the end of 1998. In the UK, however, if you are currently receiving an analogue picture that is free from interference, you already have the best picture possible. Digital TV will offer no improvement to you.

Editor:Wang  Source: