Digital television in the United States supports multiple digital subchannels if you divide the 19.4 Megabits-per-second (Mbps) bitstream. Full quality 1080i HDTV requires 18Mbps; however, many stations compress this down to 11Mbps. A 720p HDTV signal can be compressed to 8Mbps, and a SD signal compressed to 6Mbps without perceivable loss of quality. 4Mbps or less yields acceptable results if the subject in the video moves very little (such as a slideshow automated weather channel). It has been suggested that Digital terrestrial television be merged into this article or section. ...

Therefore, station managers could run any of the following scenerios:

Scenario A: 1 x Uncompressed 1080i HDTV

Scenario B: 1 x Compressed 1080i HDTV + 1 x Compressed 720p HDTV Subchannel

Scenario C: 1 x Compressed 1080i HDTV + 1 x Compressed SD Subchannel + (Optional Slideshow type subchannel)

Scenario D: 3 x Compressed SD Channels

Scenario E: 4 x Highly Compressed SD Channels

Many PBS stations around the country broadcast 4 SD channels during the daytime, and 1 HD + 1 DT channel at night. PBS offers the following channels: PBS DT, PBS HD, PBS Kids & Family, PBS Select, & PBS Learner. PBS re-directs here; for alternate uses see PBS (disambiguation) PBS logo The Public Broadcasting Service (PBS) is a non-profit public broadcasting television service with 349 member TV stations in the United States. ...