Radio mode, function - GF82.60-P-2001RMU
MODEL 230.4 as of 1.7.04 with CODE (494) USA version
After the "Radio mode" function has been activated by pressing the "FM/AM" button on the COMAND operating, display and controller unit (A40/3) in the "Audio" menu, and depending on the roof position (open, closed), the AM antenna in the rear window with the rear window antenna amplifier module (A2/12) or the rear shelf antenna (A2/68) with the rear shelf antenna amplifier (A2/67) receives high-frequency signals for medium wave (MW).
The FM antennas in the front windshield receive high-frequency signals for ultra-short wave (FM) and relay these to the left antenna amplifier module (A2/64). The music, voice and data signals are superimposed on these radio frequency signals. The left antenna amplifier module (A2/64) filters the radio frequency band frequencies and amplifies these.
The amplified signals are then sent via a coaxial cable to the radio tuner in the audio gateway control unit (N93/1). The radio tuner separates the useful information (audible frequencies) from the carrier signal (inaudible). The demodulated audio signals are amplified and converted into sound signals by the vehicle speakers.
Antenna diversity, function
In the case of the "antenna diversity" function, reception-dependent switching over is carried out between the FM antennas of the front windshield. The function proceeds automatically and is carried out by the left antenna amplifier module (A2/64). The radio tuner in the audio gateway control unit (N93/1) only generates the intermediate frequency signal. The intermediate frequency signal is used by the left antenna amplifier module (A2/64) as a reference for switching FM antenna.
The radio receiver in the audio gateway control unit (N93/1) automatically generates a list of FM stations received after the COMAND operating, display and controller unit (A40/3) is switched on; the list is constantly updated during operation. This list appears, sorted alphabetically, when the "FM station list" menu is called up. The displayed stations can be activated through selection and confirmation.
The list of stations is only available when the "Radio Broadcast Data System (RBDS)" function has been activated. If reception problems occur while driving, the COMAND operating, display and controller unit (A40/3) tries to receive the selected station on an alternative frequency with the aid of the integrated 2nd receiver and then tries to switch over accordingly if reception improves.
RBDS function
Apart from the normal radio program, many radio stations (FM stations) transmit additional digital information such as station names, program type (e.g. pop, culture, etc.) and traffic radio recognition.
This information is evaluated by the COMAND operating, display and controller unit (A40/3) if:
- An RBDS station has been tuned to
- The "RBDS" function has been activated
The radio component in the audio gateway control unit (N93/1) also offers:
- a station list of the currently most powerful FM stations in RBDS mode
- An automatic memory for the strongest AM stations
- a selection of program type (e.g. pop, culture, etc.) for FM stations in RBDS mode
Station selection options are:
- Automatic station search with scan function (the stations of one waveband are played for 8 s)
- Station search on multifunction steering wheel (MFL)
- Manual station search
- Station selection using list of stations
- Station selection by entering the frequency (e.g. 92.2 MHz)
- Station selection from the memory (10 stations per waveband)
Satellite digital audio radio (satellite radio) (SDAR)
It is possible to receive digital satellite stations. The prerequisite is that this has been enabled by a network provider. If the system is enabled, additional stations can be received. The SDAR control unit (N87/5) decodes the S-band satellite signals received by the SDAR antenna (A2/82) and forwards them over the Media Oriented System Transport (MOST) to the COMAND operating, display and controller unit (A40/3). The satellite radio function can be called up in the audio menu.
The "Satellite radio" function is provided as factory-installed special equipment in the vehicle. Thus, not only the complete wiring is installed in the vehicle, but also the SDAR antenna (A2/82) and the SDAR control unit (N87/5).
Since YoM 07/1 the SDAR control unit (N87/5) (3rd generation) has been used, and now it is also available for vehicles with code (460) Additional parts, Canadian vehicles. The SDAR control unit (N87/5) (3rd generation) differs from the previous generations on account of the following features:
- Shorter response times
- Improved reception properties
- Temperature and electromagnetic compatibility (EMC) properties have been optimized
| Audio gateway control unit, location/task/design/function | GF82.62-P-3102RM | ||
| Antenna amplifier module, location/task/design/function | GF82.62-P-3105R | ||
| Rear window antenna, location/task/design/function | GF82.62-P-3106R | ||
| Windshield antenna, location/purpose/design/function | GF82.62-P-3112R | ||
| Rear shelf antenna, location/task/design/function | GF82.62-P-3113R | ||
| Operating-display unit with control unit, location/task/design/function | GF82.85-P-3114RMU |