TV tuner, function - GF82.60-P-3109-02TA
Function requirements:
- On-board power supply
- Authentication positive
- Circuit 15R ON
Function
The TV tuner (A2/10) communicates with the COMAND operating, display and control unit (A40/3), the audio gateway control unit (N93/1) and the other system components via the built-in MOST ring interface. Basic controls of the TV tuner (A2/10):
- 4-fold antenna diversity, separated into video and audio signals
- Audio antenna diversity
- Video antenna diversity
- Multistandard receiver for PAL, Secam and NTSC
- Multistandard signal processing
TV tuner modules for audio and video
The TV system operates with a total of 3 reception modules, whereby 2 tuners are used for video processing and one tuner is used for the sound signal. The PLL tuners used cover a reception range of 45 to 866 MHz. The reception range is divided up internally into 3 bands (VHF low, VHF high and UHF). Each band has its own controllable pre-stage. The tuner outputs are of a symmetrical design. The TV tuner (A2/10) has 4 antenna inputs, into which signals are fed from the car antennas (ideally supplementing each other).
The antenna inputs are assigned to the 3 TV receiver units as follows:
- Ant 1, Ant 2, Ant 3, Ant 4 are assigned to the audio receiver unit
- Ant 1, Ant 2 are assigned to video reception path 2
- Ant 3, Ant 4 are assigned to video reception path 1
Each receiver unit can automatically select the most suitable input signal. Audio and picture antenna diversity work separately from each other in order to avoid unpleasant interference noises or picture obliteration during mobile reception.
The TV tuner (A2/10) is designed to receive television signals in the majority of Europe.
Multistandard signal processing
The signals from the TV tuner (A2/10) that have been mixed to intermediate frequency (IF) level are demodulated during subsequent signal processing. Both positive and negative amplitude-modulated signals can be processed. The demodulation stage for the sound signal receives a narrow-band filtered intermediate frequency signal which has virtually no video part and cannot cause any further sound interference. The audio signals are "AM" or "FM" depending on the TV standard.