How accessDTV Works


If you have read How Digital Television Works, then you are familiar with the world of DTV. Here is a quick summary of the important points:

  • Broadcasters in your area have each been allocated a new channel for their DTV broadcasts.
  • The broadcasters each transmit a 19.39-Mbps stream of digital data. This signal contains television programs compressed using the MPEG-2 compression system.

DTV shows can be broadcast at several different resolutions:

  • 480p - The picture is 704x480 scan lines sent at 60 complete frames per second.
  • 720p - The picture is 1280x720 scan lines sent at 60 complete frames per second.
  • 1080i - The picture is 1920x1080 scan lines sent at 60 interlaced frames per second (30 complete frames per second).
  • Broadcasters can transmit either a single 1080i high-definition channel that consumes the entire 19.39-Mbps stream, or several different sub-channels by encoding multiple programs at 480p resolution and lower bit rates.

For example, the DTV station 53 can have sub-channels named 53.1, 53.2 and 53.3. accessDTV can record and play back the sub-channels.

The accessDTV Digital­ Media Receiver Solution consists of hardware and software. The hardware is a PCI card that you install inside your PC. The software controls the card and allows you to tune in and view DTV broadcasts in your area, using either your computer monitor or an external HDTV display.