GF82.60-P-3020RC Digital Audio Broadcasting (DAB), Function

GF82.60-P-3020RC Digital Audio Broadcasting (DAB), Function
- with CODE (537) Digital radio
- with CODE (833) Great Britain version


Function requirements
^ Status "Circuit 30 ON" or "Circuit 15R ON"
^ System is authorized and operating properly
^ Rod antenna (A28), left antenna amplifier module (A2/64), and DAB L-band antenna (A95/1) are operating free of faults

Depending on the equipment version, one of the following audio devices is installed (hereinafter called "Audio unit"):
- Radio (A2), with code (510) Audio 20 including CD changer
- Radio and navigation unit (A2/56), with code (525) MB Audio 50 APS radio or with code (511) Audio 50 APS with DVD changer
- COMAND operating, display and controller unit (A40/3), with code (527) COMAND APS with single DVD drive (with navigation) or with code (512) COMAND APS with DVD changer

General
The Digital Audio Broadcasting (Digital Radio) (DAB) function makes it possible to transfer several programs on one frequency; these programs are called the "Ensemble". Up to 64 frequencies are available fro DAB; in Great Britain, up to 7 of these frequencies can be received simultaneously; as a rule, this number is 2 to 3 frequencies. An "ensemble" can consist of up to 12 programs. Each program can have subprograms (e.g. news announcement, summary of events, etc.). Only the "ensemble name", not the frequency, is displayed for the individual "ensembles".

DAB is a digital radio mode which eliminates the usual "FM/AM noise". However, short-term interruptions in reception of the "ensembles" are possible, because with DAB only two reception states are possible "Complete reception" or "No reception". The Digital Audio Broadcasting control unit (N87/3) allows reception of "Ensembles" in DAB format. Control of the DAB functions is accomplished on the "audio unit". The information and displays required for control are output on the "audio unit" display.

Operating instructions
DAB can be operated using the following components:
- Left multifunction steering wheel button group (S110) and right multifunction steering wheel button group (S111)
- Control buttons on "Audio unit"
- Voice control of the voice control system (VCS [SBS]), with code (511) Audio 50 APS with DVD changer, with code (527) COMAND APS with single DVD drive (with navigation) or with code (512) COMAND APS with DVD changer

It is only possible to select stations in the memory list or station list with the multifunction steering wheel button groups. The "Ensemble" can only be changed using the control buttons at the "audio equipment" or the VCS [SBS] voice control.

Function sequence for DAB radio
- The DAB L-band antenna receives the DAB L-band signals for the local providers, usually from conurbation stations.
- The rod antenna and the left antenna amplifier module receive the DAB band III signals for large-area provision, usually from stations with a large range or national stations.

The signals are forwarded to the Digital Audio Broadcasting control unit using coaxial cables. The Digital Audio Broadcasting control unit decodes the signals and transfers these in the form of PCM (Pulse Code Modulation) signals via the Media Oriented System Transport (MOST) to the "Audio unit".

On vehicles with code (810) Sound system, the Digital Audio Broadcasting control unit transfers the PCM signals for audio output, via the MOST, to the sound system amplifier (N40/3). From there, the PCM signals for audio output are output via direct lines over the following speakers:
- Left door speaker group (H4/1)
- Right door speaker group (H4/2)
- Left rear speaker (H4/7)
- Right rear speaker (H4/8)
- Center cockpit speaker (centerfill) (H4/27)
- Left door tweeter (H4/33)
- Right door tweeter (H4/34)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)

On vehicles, except code (810) Sound system, the Digital Audio Broadcasting control unit transfers the PCM signals for audio output over the MOST to the "Audio unit". From there, the PCM signals for audio output are output via direct lines over the following speakers:
- Left door speaker group
- Right door speaker group
- Left rear speaker
- Right rear speaker
- Center cockpit speaker (centerfill)
- Left door tweeter
- Right door tweeter