HD radio
HD Radio is the U.S. approach to digital broadcasting that competes with the European Digital Audio Broadcast( DAB). The system uses the FM broadcastfrequency range and also the medium wave( MW) range between 0.5 MHz and 1.6 MHz for digital broadcast transmissions.
HD Radio uses existing broadcast infrastructures and is forward and backward compatible with existing receiving equipment, so that the switchover can be made continuously without affecting broadcast transmissions. The technology used is In Band On Channel( IBOC), where the analog and digital signals are broadcast on the same frequency.
In addition to broadcasting the audio signals, HD radio can also transmit additional information about the piece of music, the artist or the music album as ID3 tags.
With the addition of new information services, such as traffic, weather and financial information, as well as navigation aids, a SMIL-basedprogramming language, HD Broadcast Multimedia Language (HD BML), is also expected to increase functionality.
For HD radio, the HDC codec is a compression surround technology for 5.1; in addition, HD radio can also transmit MPEG surround. In the USA, HD-Radio competes with the payradio systems "XM Satellite Radio" and Sirius Satellite Radio.