04-16-2009, 03:40 PM
It's digital radio.
Stations on both AM and FM can use a chunk of their spectrum to transmit one or more digital signals as well as the usual analog signals. Sometimes they offer different programming via digital.
It's not HD in any real sense. In fact, it's massively compressed and suffers dropouts akin to the stutters and brief loss of picture you might observe in a digital television broadcast.
Stations on both AM and FM can use a chunk of their spectrum to transmit one or more digital signals as well as the usual analog signals. Sometimes they offer different programming via digital.
It's not HD in any real sense. In fact, it's massively compressed and suffers dropouts akin to the stutters and brief loss of picture you might observe in a digital television broadcast.