Ooohh, a topic I know a little bit about since one of my clients manufactures the broadcast side hardware/encoding devices here in Japan.
But no time
I have to do some work today...
First, there are 3 Digital standards:
European DVB system
The US ATSC system
The Japanese system ISDB which is related to DVB.
Technically, the Japanese system is better, but the US standard was developed just to be different, the same as 3G cell phone standards. The cell phone difference was more centered on IPRs, but the HDTV and DVB standards were set out of fear that the US would lose domestic market viability.
All can theoretically convert PAL and NTSC. Japan pioneered analog HDTV (1035i and called Hi-Vision, which is still around and looks great) in the earky 1990s. Yes, I said 1990s. I was shocked when I first came here and saw it. It's been around for over 10 years now and commonplace.
Japan started terrestrial digital 2 years ago. The market and approach is different, but I don't have time to explain why right now. Japan is already getting ready to jump a generation in technology and go to Ultra-High Definition TV, which is 16 times better than HDTV.
I've seen it and it's astounding. Most people in the US have never really seen 'true' HDTV (unless you've seen it in a lab) because the broadcast side cameras, coders and transmitters are not state of the art. They are mostly early generation stuff.
Got to go! I'm late!