Tuner Unit: Notes

The tuner unit is a separate digital radio tuner interface. Received AM/FM radio waves are processed on the digital signal processor (DSP) and sent to the audio unit via the dedicated digital audio line (SPDIF1). At this time, the HD radio (TM) sound signal is separated from the normal AM radio sound signal. All of the information about AM/FM reception (includes RBDS information) are sent from the tuner unit via the dedicated serial bus (TUNER RS485). This unit holds AM/FM radio frequency presets even when the 12 volt battery is disconnected.

For vehicles with Sirius XM (R) radio, the antenna for receiving AM/FM radio waves and satellite/terrestrial (XM) signal uses a roof antenna type. AM/FM radio wave is amplified by the AM/FM antenna amplifier. The sensitivity of the FM wave is raised by the auto gain control. The XM antenna receives satellite signal and terrestrial signal by using the high-gain antenna. Signals are sent to the audio unit via the dedicated single line (SAT/TER).