Basically, digital radio works the same as conventional radio. There’s a signal on one end and a receiver on the other. But there are a few key differences.
 Instead of sending out one analog signal, stations send out a bundled signal – both analog and digital. Because it is digital, textual data such as traffic, stock info and song titles can be sent out, as well.
 The digital signal layer is compressed.
 The combined analog and digital signals are transmitted.
 Inevitably, radio signals bounce off objects, causing what is called multipath distortions. This is what causes the static in conventional radio receivers. HD Digital radio receivers are designed to sort through reflected signals, reducing static, hiss, pops and fades.
 Finally, the signals reach their destination. Both broadcasts are free, with no subscription fee. To hear the digital broadcast, all you need is an HD Radio receiver.
HD Radio Receiver iPod tagging Texas High Definition Radio stations