Here's a few facts:
The U.S. is one of the few countries in the world to use 8-VSB instead of COFDM modulation for OTA (over the air) digital TV. The later offers more redundancy and is generally used where 8 MHz of bandwidth is available, and works better with moving vehicles. 8VSB is generally used in 6 MHz of bandwidth and allows for some extra information or features and relies upon improvements in tuners to deliver pictures in less favorable conditions (such as multipath). And some state "...that 8-VSB offers a number of advantages over COFDM for broadcast DTV service, including superior overall coverage, lower costs of construction and operation, and immunity to impulse noise from household appliances." See the bottom article
here if you want more info.
(The U.S. is the only country in the world that will continue the use of the VHF band for television after the analog transmissions are ended and digital transmissions take over. The rest of the world has moved OTA digital television to the UHF band exclusively.) Disregard- incorrect. See following posts. Should read "The U.S. is one of the very few....."
The old analog OTA TV system in the U.S. was called NTSC. The new digital OTA TV system is called ATSC.
The U.S. generally uses 60 Hz refresh rates while most/all of Europe uses 50 Hz.
The FCC (Federal Communications Commission) has established the below table for digital TV in the U.S. - called "Table 3" :
ATSC Table 3 Formats for DTV Transmission
Vert----------horz---------aspect----------fps/scan
1080----------1920----------16:9--------24p, 30p, 30i
720-----------1280----------16:9--------24p, 30p, 60p
480------------704----------16:9--------24p, 30p, 30i, 60p
480------------704-----------4:3---------24p, 30p, 30i, 60p
480------------640-----------4:3---------24p, 30p, 30i, 60p
Note that only the top two lines are referred to as "HD" - the rest are "SD" or "ED." HD is a subset of digital TV.
It is common in the U.S., at least, for the "1920" to be reduced to only 1440 or 1280.
Keep in mind about interlacing, and that in theory at least, 720 60p will display motion such as sports better than 1080 30i. But many other factors affect this.