GF82.85-P-2030CEB Audio Mode, Function
GF82.85-P-2030CEB Audio Mode, Function
- with CODE (527) COMAND APS with single DVD drive (with navigation)
- except CODE (498) Japan version
- with CODE (512) COMAND APS with DVD changer
- with CODE (528) COMAND with DVD changer
Function requirements, general
^ Circuit 30g
^ Data DVD/CD inserted
General information on the audio mode
The following audio functions can be selected using the "RADIO" menu or the "DISK" menu:
^ Radio operation function (AM/FM)
^ Function sequence for DVD/CD audio and video as well as MP3
^ MUSIC REGISTER function (without code (528) COMAND with DVD changer)
The following components are available for control of the audio system:
- Control buttons on the COMAND controller unit (A40/3)
- Audio/COMAND control panel (A40/9)
- Left multifunction steering wheel button group (S110 ) and right multifunction steering wheel button group (S111)
- Voice control system microphone (B25/7) (with code (527) COMAND APS with single DVD drive (with navigation) or code (512) COMAND APS with DVD changer)
On vehicles without code (810) Sound system, the audio signals are output directly by the COMAND controller unit to the following speakers:
- Left front door speaker (H4/1)
- Right front door speaker (H4/2)
- Left rear door speaker (H4/3)
- Right rear door speaker (H4/4)
On vehicles with code (810) Sound system, the audio signals are routed by the COMAND controller unit via Media Oriented System Transport (MOST) to the sound system amplifier control unit (N40/3), where they undergo final amplification. The audio signals are directly output by the sound system amplifier control unit to the following speakers:
- Left front door speaker
- Right front door speaker
- Left rear door speaker
- Right rear door speaker
- Center dashboard speaker (H4/27)
- Bass speaker (H4/29) (model 204.0/2)
- Left rear surround speaker (H4/54)
- Right rear surround speaker (H4/57)
On model 204.0 the right rear surround speaker is integrated into the bass speaker.
On model 204.9 the audio signal for the rear bass speaker (H4/38) runs from the sound system amplifier control unit to the rear bass speaker amplifier (N40/9) and from there via direct lines to the rear bass speaker.
The subscribers of MOST are activated with circuit 15R OFF by switching on the COMAND controller unit.
Information on the station currently set or track played is shown in the instrument cluster (A1) and Audio/COMAND display (A40/8).
Radio operation function (AM/FM)
The antennas in the rear window receive the signals of the radio frequency bands FM and AM (MW, LW, SW).
The following useful signals relevant for the radio reception are modulated onto the signals:
- Music signals
- Speech signals
- Data signals (e.g. traffic information)
The signals are transmitted via direct lines to the FM, AM and CL [ZV] antenna amplifier (A2/18) (model 204.0) or to the rear window antenna amplifier 1 (A2/71) (model 204.2/9) as well as to the rear window antenna FM antenna amplifier (A2/19). The antenna amplifiers filter the frequencies of the radio frequency bands out of the received signals and amplify them. The amplified signals are then sent via coaxial lines to the tuners integrated into the COMAND controller unit where they are demodulated and then output over the speaker system.
The radio mode (AM/FM) function is made up of the following subfunctions:
^ Function sequence for AM reception (MW, LW, SW)
^ Function sequence for FM reception
^ Traffic Announcement (TA) function (traffic information) (without code (494) USA version)
^ Radio data system (RDS) function (without code (494) USA version) or Radio Broadcast Data System (RBDS) reception (with code (494) USA version)
^ Function sequence for high-definition (HD) radio mode (with code (494) USA version)
Function sequence for AM reception (MW, LW, SW)
For the MW, LW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM).
These signals are demodulated by the AM tuner integrated into the COMAND controller unit. In other words, it also separates the useful signals (audible frequencies) from the carrier signal (inaudible). The COMAND controller unit also enables an automatic, reception-specific changeover between the antenna amplifiers.
Function sequence for FM reception
For the FM radio frequency band, the useful signals are transmitted using frequency modulation. These signals are demodulated by the FM tuner integrated into the COMAND controller unit. In other words, it also separates the useful signals (audible frequencies from the carrier signal (inaudible). The COMAND controller unit also enables an automatic, reception-specific changeover between the antenna amplifiers.
TA function (traffic information) (without code (494) USA version)
If the COMAND controller unit receives a traffic announcement (TA) while a radio station or a CD/DVD is in operation, the traffic announcement is given priority, i.e.:
- The volume of the traffic announcement is increased for radio operation.
- If a CD/DVD is playing, it is stopped and the traffic announcement made.
Additional function requirements of RDS (without code (494) USA version) or RBDS reception (with code (494) USA version)
^ Function activated
^ Radio stations also transmit additional digital information
RDS function (without code (494) USA version) or RBDS (with code (494) USA version)
Apart from the normal radio program, many radio stations (FM) transmit additional digital information such as station names, program type (PTY) (e.g. pop, culture, etc.) and traffic program identification. This information is evaluated by the COMAND controller unit and shown on the Audio/COMAND display.
Function sequence for HD radio mode (with code (494) USA version)
The HD radio function is implemented in the COMAND controller unit. The integrated HD tuner is a combined AM/FM/Weatherband (WB) receiver with HD radio function. It demodulates the analog AM and FM signals using the two integrated double tuners and decodes the digital AM and FM signals using the integrated HD radio decoder chips.
The weatherband feature allows reception of US weatherband signals.
The HD radio function also allows additional reception of digital carrier waves for analog AM/FM programs, which are also broadcast by the stations.
The HD radio function improves the audio quality using digital technology:
- FM (96 kBit/s):
- CD sound quality (no "multipath interferences")
- AM (36 kBit/s):
- FM sound quality (stereo)
The stations also broadcast other audio channels and data with the digital carriers. This supplements the program with up to 2 additional audio channels per frequency (e.g. foreign language program from National Public Radio (NPR)) and supplemental information (e.g. title and artist) can be received.
Additional transmission of digital carriers is designated as "On Channel", the digital station is tuned to the same frequency as the analog station.
The digital transmission process in the FM and AM band is known as "in-band".
In contrast to the satellite digital audio radio (satellite radio) (SDAR) function (with code (536) SIRIUS satellite radio) regional stations and programs are received by the HD radio function and no fees will be charged
Function sequence for DVD/CD audio and video as well as MP3
The DVD/CD audio and video function can be used to play audio CDs or audio DVDs (including MP3 format) as well as video CDs or video DVDs. User guidance for controlling DVD/CD functionality and displaying supplemental information is carried out via the Audio/COMAND display.
Data exchange between the COMAND controller unit and the Audio/COMAND display is performed via the telematics CAN (CAN A). The video signals are sent via the low voltage differential signal (LVDS) line.
The DVD/CD menu and the Track menu, which are shown on the Audio/COMAND display, are stored on the inserted DVD/CD. For this reason, the function scope and menu display are dependent on each respective medium.
In the event that one of the two menus is missing on the DVD/CD, the corresponding menu item is highlighted with a gray background on the Audio/COMAND display on the COMAND controller unit.
MUSIC REGISTER function (without code (528) COMAND with DVD changer)
On the integrated hard drive in the COMAND controller unit, files (in the MP3 format) from a CD/DVD or a Personal Computer Memory Card International Association (PCMCIA) card can be stored and then called up again as and when required.
