iankh
It's never done till it's overdone
- Joined
- Jan 8, 2005
- Messages
- 7,181
The information in the signal itself coming over the air is now digital, as opposed to the old analogue signal.
An older TV knows how to read and translate the analogue into a picture and sound but does not know how to translate the digital information.
The newer TVs are capable of translating that digital information. The converter boxes they are selling for older TVs do the same thing, they take the digital information, and turn it into analogue information that is under stood by the older sets.
Newer TVs have the ability to "understand" the digital information built in.
Cable and Satellite do not need this, because the delivery mechanism is not broadcast through the air, but via a physical cable or via a satellite.
The whole reason for digital broadcasting is that it opens up airspace. Digital takes up less space than analogue.
Another very good way to under stand analogue and digital are records and CDs.
Vinyl records are analogue. They have physical sound waves (grooves) that cause a needle to vibrate, and then that physical energy is converted into sound.
CDs are digital (which is a series of zeros and ones), or data that are read by a beam of light and translated into sound.
Here's another analogy. They are now selling turntables for vinyl that have USB connections to allow you to convert records to MP3 and digital format.
Those turntables (like the new TVs) have a built in converter that takes the information in the physical sound waves (grooves) and converts it into a digital format (zeros and ones) so that it can be used by a computer, which only understands digital information.
Digital is more compact than analogue, so just like a CD can old more music than a vinyl record, digital television broadcasting also takes up less physical space, so going digital opens up air bandwidth and airspace.
Cheri!! 
