GF82.85-P-2011RA TV Operation, Function

GF82.85-P-2011RA TV Operation, Function
- with CODE (352) COMAND operating and display system
- with CODE (860) TV tuner
- except CODE (491) USA version
- except CODE (498) Japan version

Component Identification:

TV mode
The LCD color display of the COMAND operating, display and control module (A40/3) is used for television reception.
TV reception is possible up to approx. 8 km/h and can be activated with the present TV button
Moreover, the system can be controlled from all seats with an infrared remote control. The TV tuner (A2/42) is installed in the rear on the left side.

The audio signals are preamplified by the COMAND operating, display and control module (A40/3) and the required tone settings (volume, bass, treble and fader) are made.

TV mute, function
The mute function of the audio sources is maintained when it was activated before switching off.

Displaying mute status on the TV screen
If mute is set, a symbol appears in the top right of the display. It is necessary for the mute status to be transmitted to the TV tuner (A2/42) with a newly generated command so that the mute status can be displayed on the TV screen.

The setting which was performed last before switching off the ignition, is adopted when the ignition is switched on again.

TV tuner system
The TV tuner (A2/42) supplies the video and audio information which is reproduced by the COMAND operating, display and control module (A40/3).

TV tuner components and functions
^ 4-fold antenna diversity, audio and video are separate
^ Audio antenna diversity
^ Video antenna diversity
^ Frequency diversity (when the VPS signal is present)
^ Picture diversity
^ TV tuner module for audio and video
^ Multistandard PAL/Secam receiver for greater ECE area

4-fold antenna diversity
To prevent interference noise or loss of picture during mobile reception, the audio and video antenna diversity operate separately from one another. The signals received by the antennas are relayed to the TV tuner (A2/42) via 4 antenna inputs. The best signal is selected by the receiver on its own.

Audio antenna diversity
An adaptive quality signal derived from the AF audio signal i provided to the central processing unit. After completing a programmable decision-making process, the antenna is changed.

Video antenna diversity
The video signal quality evaluation requests an antenna switchover from the central processing unit. A switchover signal is then output switching on the alternative antenna of the requesting video path. When this antenna is better for the signal, it is retained.

Frequency diversity (when VPS signal is present)
The vertical blanking gap of the picture signal (data line) contains numerous information, which control, for example, the recording times for video recorders or permits the display of television text. The station is identified by a numerical station code (in the data line).

TV tuner modules for audio and video
3 reception modules, consisting of 2 tuners for picture processing and one tuner for the sound signal, work for the TV system. The PLL tuners cover a reception range from 45 to 866 MHz.

As of 1.7.02 the TV system works with a total of 3 reception modules, whereby each tuner can be used for processing pictures and sound.

The reception range consists of three bands: VHF low, VHF high and UHF. Each of these three bands has its own controllable preliminary stage. The tuner inputs are carried out symmetrically. The TV standard BG, I, L, LS and MN can be received.

Multistandard signal processing
The signals mixed to the IF level (Intermediate Frequency level) by the tuners are demodulated in the subsequent signal processing stage (positive and negative amplitude-modulated signals). The demodulation stage for the audio signal receives a narrow band filtered IF signal. This signal has virtually
no video signals and therefore does not cause audio interference. The audio signals are "AM" or "FM" depending on the TV standard. The AM audio is demodulated in the first Intermediate Frequency and the FM audio at a lower, second Intermediate Frequency.

Quality evaluation
During a process, a DC voltage corresponding to the signal quality is obtained from the AF signal by filtering. The TV standard is recognized by this DC voltage; this simultaneously serves as the decision criterion for the frequency diversity sequence control. The soft-mute and high cut control function is regulated with the DC voltage for suppression of interference with extremely weak signals.

AV input (FBAS)
Two connectors for external sources such as video player or DVD player are present in the tuner box. The video input format is the FBAS signal with U = 1V amplitude.
The video source outputs are connected to the AMP/MQS tuner box inputs by an adapter cable.

Day/night design function
If Front is set in the Car Status on CAN B for night design, then the color tables are loaded with the colors for night design in the megatext module.
As a direct connection between colors and symbols shown on the display exists, the menu display is immediately adjusted to the new colors, even if just one menu is active. When the CAN-B bus for night design is deleted, the color tables with the colors for the day design are loaded.

Languages
^ German
^ English
^ English (United States of America)
^ French
^ Italian
^ Dutch
^ Spanish

On model 203 as of 1.7.02 the switch-off threshold for TV mode has been reduced from a speed of 8 km/h to 6 km/h.