Audio mode, function - GF82.85-P-2030GQD

MODEL 164.1 with CODE (523) MB Audio 20 radio as of model year 09/YoM 08 model refinement package

MODEL 164.8 with CODE (523) MB Audio 20 radio as of model year 09/YoM 08

MODEL 251.0 with CODE (523) MB Audio 20 radio as of model year 09/YoM 08

MODEL 251.1 with CODE (523) MB Audio 20 radio as of model year 09/YoM 08

Function requirements

Status "Circuit 30 ON" or "Circuit 15R ON"
The radio is authorized and in perfect working order
No fault in antenna system (radio function)
Audio-CD is inserted (for disk operation)
A radio data system (RDS) station is set and the RDS function is activated
Radio stations also transmit additional digital information
Traffic Announcement (TA) function set on the radio (A2)

General audio mode function sequence

The audio mode function consists of the following function sequences:

Radio operation (FM/AM/SW/LW/MW) function sequence
Disk function sequence

Operating instructions

Control, selection or adjustment of the audio functions is possible with the following components:

Left multifunction steering wheel button group (S110) or right multifunction steering wheel button group (S111)
Control buttons on the radio

Radio operation (FM/AM/SW/LW/MW) function sequence

The rear window antennas or the FM/AM/RRCL [FZV] antenna (A2/93a1) in the roof antenna module (A2/93) receive high frequency (HF) signals for the FM and AM (MW, LW, SW) radio frequency bands. The following useful signals relevant for the radio reception are modulated onto these HF signals:

Music signals
Speech signals
Data signals (e.g. Traffic Message Channel (TMC) messages (traffic information))

The HF signals from the rear window antennas are forwarded via direct lines to the FM rear window antenna amplifier (A2/19) and from there to the roof antenna module. These two amplifiers filter the frequencies of the radio frequency bands out of the received HF signals and amplify them. The amplified signals are then sent from the roof antenna module via coaxial lines (FM, AM) to the tuner integrated in the radio where they are demodulated and undergo final amplification.

The demodulated audio signals are output directly on the following speakers by the radio:

Left front door speaker (H4/5)
Right front door speaker (H4/6)
Left rear door speaker (H4/3)
Right rear door speaker (H4/4)
Left front door tweeter (H4/33)
Right front door tweeter (H4/34)
Left rear door tweeter (H4/35)
Right rear door tweeter (H4/36)

The function sequence for the radio mode also consists of the following subfunctions:

Function sequence for AM tuner (MW, LW, SW)
FM double tuner function sequence with phase diversity (FM)
TP traffic information function sequence (FM only)
RDS function sequence (with FM only)

Function sequence for AM tuner (MW, LW, SW)

For the MW, LW and SW radio frequency bands, the useful signals are broadcast using amplitude modulation (AM). The AM tuner integrated into the radio demodulates these signals. I. e. it separates the audio signals (audible frequencies) from the carrier signal (not audible).

FM double tuner function sequence with phase diversity (FM)

For the FM radio frequency band, the useful signals are broadcast using frequency modulation (FM). The FM tuner integrated into the radio demodulates these signals. I. e. it also separates the audio signals (audible frequencies) from the carrier signal (not audible). The radio also enables an additional reception-specific changeover between the two antenna amplifiers. This function runs automatically.

TP traffic information function sequence (FM only)

If the radio receives a traffic announcement while a radio station or a CD is playing, the traffic announcement has priority, i.e.:

The volume of the traffic announcement is increased for radio operation.
If a CD is playing, playback is stopped and the traffic announcement made.

RDS function sequence (with FM only)

Digital, inaudible information such as station names, types of program (PTY) (e.g. pop, classic) and traffic program identification is evaluated by the radio and displayed on the radio display.

Disk function sequence

The disc function sequence comprises the following subfunction sequences:

CD function sequence or MP3
AUX function sequence

CD or MP3 function sequence

A CD drive is integrated into the radio. The CD drive is used to read in the audio CDs (including in MP3 format) and they are internally processed by the radio. The user guidance for control of the CD functions (e.g. track selection) and for showing supplemental information (e.g. title) is accomplished on the radio display.

The audio is then output directly via the radio on the following speakers:

Left front door speaker
Right front door speaker
Left rear door speaker
Right rear door speaker
Left front door tweeter
Right front door tweeter
Left rear door tweeter
Right rear door tweeter

AUX function sequence

If an external device (e.g. MP3 player) is connected via the AUX jack and the "AUX" menu item is called up, the corresponding base screen is displayed in the radio. The following information is shown on the radio display:

Status line
- No display
Field of application
- No display, 2 speaker symbols only
Function bar
- "AUX" and "Tone"

The associated submenus can be called up on the radio display in the following menu items:

"AUX" menu item
- No other submenus
"Tone" menu item
- Treble
- Bass
- Balance/fader

The menu navigation and display of the connection options are shown on the display of the radio and are dependent on the respective portable terminal connected.

The audio is then output directly via the radio on the following speakers:

Left front door speaker
Right front door speaker
Left rear door speaker
Right rear door speaker
Left front door tweeter
Right front door tweeter
Left rear door tweeter
Right rear door tweeter

Electrical function diagram for audio mode, function	Model 164	PE82.60-P-2058-97MAA
Electrical function diagram for audio mode, function	Model 251	PE82.60-P-2058-97RAA
Radio control panel, component description	A2	GF82.60-P-3116GQ