HDTV is High Resolution Digital Television (DTV) combined with Dolby Digital Surround Sound. The results are crystal clear high resolution images and unbelievable surround sound audio. All-digital HDTV broadcasts as many as 10 times more pixels than standard TV. Standard TV usually displays around 210,000 pixels, and HDTV displays between 1 million and 2 million pixels. A 16:9 HDTV widescreen aspect ratio transmits images like they were intended to be seen, compared to a standard TV which has an aspect ratio of 4:3.
HDTV is “interlaced”, a term used to descibe the scanning system. Using interlacing, an HDTV screen shows the odd lines during one scan of the screen, and the even lines during the following scan of the screen. An HDTV shows 30 screen frames per second, so 30 times per second, the screen shows half of the lines and then shows the other half of the lines.
One important aspect of HDTV is the need for data compression of the signals. MPEG-2 is used to compress digital signals in order to reduce their bandwidth while being transmitted. This type of compression often reduces the bandwidth required by a ratio of 55:1. The compressed signals can then be transmitted via satellite, and used by lower bandwidth applications.
An HDTV receiver is required for this service in addition to an HD compatible TV and the source of HDTV broadcast (satellite or cable). If you desire to watch HDTV shows on analog TV, the cheapest way to see them would be to buy an HDTV converter, although HDTV shows that you see on an analog TV will be no better than DVD quality, because the resolution and formatting of an HDTV set will be absent. A genuine HD compatible TV will provide outstanding functionality with HDTV programs.