IBOC: In Band On Channel
WARNING: This page is about a different car, the 2013 BMW X5, 2012 BMW X5, and 2011 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
The IBOC control module of the High Definition Radio is designed as a hybrid tuner for reception of digital and analog radio stations in the AM and FM frequency ranges. To receive the digital signals, the same signal path is used as for reception of the analog signals. This means that the familiar components 'antenna amplifier with diversity module' and 'AM and FM antennas' can be used.
The IBOC control module decrypts the digital audio data and sends it across the MOST bus (Media Oriented System Transport bus) to the head unit. The head unit transforms the audio data into analog LF signals. The LF signals are output across the loudspeakers.