What is Digital Television?
Digital television is an exciting new way of broadcasting which involves converting the pictures and sound to data signals, compressing these and then transmitting only the changed detail. It is an efficient way of providing better quality pictures and sound whilst reducing the amount of signal bandwidth required.
The switchover from analogue to digital is now regionally underway in the UK and by 2012 all TV broadcasting will be digital.
Digital television in detail
How digital television works
Digital is the transmission of TV where all the elements are converted into a stream of pure binary numbers. By exploiting redundancies in the stream not all the information about every part of every frame needs to be transmitted. Just consider a sequence of television pictures as a section of movie film; it's obvious that one frame is very like the next and very little changes from frame to frame in any particular sequence. As long as the first frame in any given sequence is defined, it isn't necessary to transmit everything, only the bits that change significantly from frame to frame need be transmitted. All the rest is redundant information.
Exploiting redundancies
Exploiting redundancies means that digital television can be compressed. Much less information needs to be transmitted than with an analogue signal, so significantly more channels can be broadcast over the same broadcast system.
Self-repair signal
In addition, the use of pure numbers means that methods can be employed to allow the signal to 'self-repair' and automatically correct errors caused by interference. The result is a picture and sound quality that remains consistently excellent regardless of interference that would make analogue viewing impossible.