Specs NTSC HDTV
Aspect Ratio 4 : 3 16 : 9
Frame Rate 30 frames per second 60 frames per second
Resolution 480 horizontal resolution lines 720 or 1080 horizontal resolution lines
Vertical Refresh Rate 60 Hz 60 Hz

Timeline
     October 1998: HDTV transmissions begin at 26 stations in the top 10
     markets

     May 1999: network affiliates in the top 10 markets must show at least
     50% digital programming

     November 1999: digital broadcasts in the next 20 largest markets

     May 2002: remaining commercial stations must convert

     2003: public stations must convert to digital broadcasts

     2004: stations must simulcast at least 75% of their analog
     programming on HDTV

     2005: stations must simulcast 100% of their analog programming

     2006: stations relinquish their current analog spectrum

     http://home.earthlink.net/~greenevideo/HDTV/timeline.html


UD "http://www.physics.udel.edu/~watson/scen103/99s/projects/television/hdtv4.html"
Last Updated: May 19, 1999
Created by Diana Waxman , Jessica Bureau & Greg Roeberg