Analogue TV vs. Digital TV
History of analogue
Analogue TV broadcasting has served us well for over 70 years. However, in terms of the actual broadcasts - the production and distribution of programmes across the nation - analogue lost its exclusivity long ago and is fast reaching the end of its useful life.
The first digital service in the UK was launched in October 1998 by BSkyB and was quickly followed by the terrestrial broadcasters. Sky's analogue channels were turned off shortly afterwards and now all UK analogue services are to be phased out completely by 2012 in the Digital Switchover.
The digital solution
Digital helps solve the scarce frequency problem by delivering a more efficient use of frequency band than the analogue method. The technique of digital compression allows a huge increase in capacity. More channels can be carried in digital format than in analogue across the same amount of frequency band.
Analogue takes up quite a lot of frequency band and cannot be efficiently compressed, so where the old satellite system could deliver up to 120 television channels the same spectrum now delivers well over 1,000 services of TV, radio, active and interactive applications. All carried across the same amount of frequency as was previously used for just 120 analogue channels.
Another advantage to digital is that it delivers a more consistent picture quality than analogue, and it does it with less signal level and through heavier interference than with the older method.
Why has digital broadcasting ousted analogue so quickly?
The answer lies in the way digital solves a serious problem that most people are unaware of, that there isn't enough frequency band to go round.