1. HD Radio digitizes and compresses the audio. It then bundles the audio with other digital data for transmission.
2. The signal is packetized and assembled into OFDM format.
3. Radio stations then transmit the signal over existing AM and FM bands.
4. Signals from multiple paths, noise and interference all reach the receiver.
5. The HD Radio sorts out the signals and presents a clean, noise-free high quality audio program to the listener.