DIYbanter - Difference between digital, HDTV and the normal TV ?

wrote in message
...
May I know the main difference between a Digital TV, an HDTV and the
normal TV ?
Thanks

By 'normal' TV I assume you mean the TV that we have been watching for the
last 50 years ? This is analogue. The transport medium by which the signal
reaches you - say an RF carrier broadcast over the airways - is modulated
with a direct analogue representation of the signal which emerges from the
studio camera or other video source. The receiving TV set process this in an
analogue form to produce the picture that you see (and the sound of course).

With digital TV, the transport medium is modulated with a digital
representation of the signal from the camera. This digital signal is complex
in that the source signal has been digitised, compressed, had error
correction added and a couple of other clever techniques applied to help
with the power / bandwidth distribution. It may also have had encryption
added for pay TV access purposes. After it has had all of this done to it,
it will be chopped up and inserted into a transport stream, along with
sometimes many other channels. The TV set will process the received signal
in digital format right up to just before the picture tube in a CRT set, or
all the way in a plasma or LCD set.

High definition TV (HDTV) is just that. The number of pixels which form the
picture, is higher than with 'standard' definition. Effectively, if you
understand the concept of how a TV picture was formed on a CRT TV, it's like
doubling the number of horizontal lines that the picture is formed from, and
likewise, the number of individual points that can be resolved along each
line.

Arfa