GF82.85-P-2030TMU Audio Mode, Function

GF82.85-P-2030TMU Audio Mode, Function
- with CODE (530) COMAND APS USA (with navigation system)
- Radio, CD, SDAR


Radio reception, function
The antennas in the rear window receive high frequency (HF) signals for ultra-short wave (FM) and medium wave (MW) as well as weather information. Modulated onto these HF signals are music, voice or data signals. The left antenna amplifier module (A2/64) filters the radio frequency band frequencies from the received HF signals and amplifies them. The amplified signals are then transmitted from the left antenna amplifier module via a joint coaxial line (FM, AM) to the radio receiver in the audio gateway control unit (N93/1).
The radio receiver demodulates the HF signals, in other words it 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.

Radio mode
The radio menu is reached by pressing the AUDIO function key on the COMAND operating, display and controller unit (A40/3). Following this, the following subfunctions can be set for the radio mode, which are shown on the display of the COMAND operating, display and controller unit:
^ AM noise suppression
^ Selection of Radio Broadcast Data System (RBDS) stations with good reception
^ RBDS functions (PS, TP, TA, EON, PTY, PTY 30/31)
^ FM antenna diversity, function
^ Station selection

Station selection
Different ways of tuning in stations:
^ Tuning by list of stations
^ Tuning by program type list
^ Tuning via frequency list
^ Tuning by station search
^ Tuning by station search on multifunction steering wheel (MFL)
^ Tuning by autostore memory
^ Tuning by scan search (the stations of a waveband are played for 8 seconds)
^ Manual tuning
^ Tuning by station memory (10 stations preset for each waveband and 7 stations in the weather band)
^ Tuning by manual frequency input (via the 12-button control panel of the operating unit)

Radio Broadcast Data System (RBDS) function (Regional mode)
In addition to the radio program, many radio stations (FM) also transmit additional inaudible digital information. These include, for example station name, program type (PTY) (e.g. pop, culture) and traffic program identification. This information is evaluated by the COMAND operating, display and controller unit and shown on the display, if an RBDS station is tuned and the RBDS function is activated.

FM antenna diversity, function
If reception faults occur while driving, the COMAND operating, display and controller unit tries to receive the selected station on an alternative frequency with the aid of the radio tuner and to switch over accordingly if reception improves. Similarly a switchover is made depending on reception quality between the rear window FM antennas. The function runs automatically and is carried out by the left antenna amplifier module.

The radio tuner only generates the intermediate frequency (IF [ZF]) signal which serves the left antenna amplifier module as a reference for changing the FM antenna.

At certain times, some radio channel programs are subdivided into regional programs. Since the COMAND operating, display and controller unit, as described above, automatically changes to an alternative station frequency in the event of reception faults, this can likewise lead to a change of the regional program. If this is not desired, the "Regional program" entry can be activated under the "FM settings" menu.

Satellite digital audio radio (satellite radio) (SDAR) (with code (536) SIRIUS satellite radio)
The system "Satellite radio" is a universal radio system, which serves to ensure sufficient coverage by means of 3 satellites and approx. 100 converters. The following additional components are required for reception in the vehicle:
^ SDAR antenna (2/49a4) (irrespective of FM and MW reception)
^ SDAR control unit (N87/5)

Since modification year 07/1 the SDAR control unit (3rd generation) has been used, which is now also available for vehicles with code (460) Additional parts, Canadian vehicles. The SDAR control unit (3rd generation) differs from previous generations through the following features:
^ Shorter response times
^ Improved reception properties
^ Temperature and electromagnetic compatibility (EMC) properties have been optimized