Antenna amplifier module, function - GF82.62-P-3105-04PS

Filtering and amplification of high frequency signals 

Electrical filters,  select the desired frequency bandwidths (AM, FM, TV,..)  from the high-frequency signals received by the side windows  and rear window  antennas.

These filters  are, depending upon the country (e.g. , ,...) of different design, as the transmission frequencies  are country specific.

The filtered frequency bandwidths  are then selectively amplified  and sent via coaxial lines  to the corresponding control modules, e.g.: 

• Radio (A2)  or
• COMAND operating, display and control module (A40/3) 

  or

• EIS control module (N73) 

Demodulation of FZV signals 

The signals for the radio controlled central locking (FZV)  are demodulated by the amplifier module 2, windshield antenna (A2/72)  and digitized. 

For the ... version, the demodulation is performed  by the amplifier module 2, windshield antenna (A2/72). 

The data processed thus is then sent over a separated data line to the EIS control module (N73)  and once there sent to the CAN interior. 

During the demodulation  the useful signal (e. g. the FZV signal)  is split up from the high-frequency carrier frequency (transmission frequency). 

Antenna diversity, function 

The diversity processor integrated into amplifier module 1, windshield antenna (A2/71)  and amplifier module 2, windshield antenna (A2/72)  is responsible for setting up a reception-sensitive switchover between the FM side window  and the FM rear window  , in order to ensure that the best possible reception  is given.

The diversity function  for TV  is assumed by the amplifier module 3, windshield antenna (A2/73)  and amplifier module 4, windshield antenna (A2/74). 

The FM antenna  function is described below:

• Firstly, the radio (A2)  or the COMAND operating, display and control module (A40/3)  receives the active FM antenna  signals from the amplifier module 1, windshield antenna (A2/71)  and amplifier module 2, windshield antenna (A2/72)  .
• The radio (A2)  or the COMAND (A40/3)  generates the intermediate frequency reference signal  from the incoming FM signals. 

This reference signal  is sent via a separated line to the amplifier module 1, windshield antenna (A2/71)  and amplifier module 2, windshield antenna (A2/72). 

• The diversity processor  of the amplifier module 1, windshield antenna (A2/71)  and amplifier module 2, windshield antenna (A2/72)  check whether the intermediate frequency signal  , is noise free after demodulation  . If faults exist, then it is automatically switched to the next of the three FM antennas  on the side  and rear windows. 
• The switchover speed  is dependent here on the frequency  of the occurring faults  .

  In the event of extremely poor FM reception  this helps to avoid a continuous switchover  between the antennas  from taking place, which in turn could cause reception  difficulties.