communications law prof karl manheim spring 2006 7 digital & high definition tv terminology advanced television atv any technology that improves audio video quality over existing ntsc standards 1940 enhanced edtv hdtv display compare computer monitors dtv signal transmission bits bytes vs analog in us is per atsc japan france adopted 1991 1997 why basic fcc decisions re the public interest if so should play role what be how much spectrum allocated who get channels can they used for non purposes happen to standard present system began 1938 initial 12 round tube 4 3 aspect 300 lines current 525 scan 480 visible x 500 pixels unused 45 vertical blanking interval vbi interlaced alternate line refresh 60 times second better possible broadcast would benefit convenience necessity image sharpness
