GF82.62-P-3121TXC Left Antenna Amplifier Module Component Description

GF82.62-P-3121TXC Left Antenna Amplifier Module Component Description
- with CODE (498) Japan version

Component Identification:

Location of left antenna amplifier module
The left antenna amplifier module (A2/64) is located behind the left C-pillar paneling.

Task of left antenna amplifier module
The left antenna amplifier module (A2/64) is responsible for the following:
^ To provide high-frequency decoupling of the voltage supply of the heater area on the rear window
^ To filter and amplify the FM and AM signals of the rear window antenna
^ To forward amplified FM and AM signals to the audio gateway control unit (N93/1)
^ To send the strongest of 4 FM signals to the audio gateway control unit (N93/1) (diversity function)
^ To filter and amplify the TV1/TV2 signals of the rear window antenna and to send them to the TV antenna selector (A2/79)
^ To receive, filter, demodulate, digitize the signals for the radio remote central locking (RRCL), as are received from the rear window antenna and to forward them to the Rear SAM control unit with fuse and relay module (N10/2)

Design of left antenna amplifier module
The following components and functions are integrated into the left antenna amplifier module (A2/64):
^ Filter, amplifier and a diversity system for the FM1 FM2, FM3 and FM4 signals
^ Filter and amplifier for AM signals
^ Filter and amplifier for TV1 and TV2 signals
^ Filter, demodulator and digitization function for the radio remote central locking signal
^ To provide high-frequency decoupling around the voltage supply's barrier circuit for the heater area

Function of left antenna amplifier module

Filtering and amplification of AM, FM, TV and radio remote central locking signals
In the left antenna amplifier module (A2/64) the FM frequency bands (FM1 up to FM4), AM frequency band and the TV frequency bands (TV1 and TV2) are filtered out and amplified. In addition to this the radio remote central locking signal is also filtered out.

Antenna diversity function (FM)
The diversity function serves to reduce reception interference. The diversity function integrated into the left antenna amplifier module (A2/64) is responsible for reception specific switching between the FM antennas (FM1 up to FM4) for the rear window, to achieve the best possible reception. Firstly, the audio gateway control unit (N93/1) receive the signals of the active antenna from the left antenna amplifier module (A2/64).

The audio gateway control unit (N93/1) generates the IF reference signal from the incoming FM signals. This reference signal is transmitted to the left antenna amplifier module (A2/64) via a separate line

Following demodulation the diversity function checks whether the IF signal is trouble-free. If interference is present, it automatically switches over to the next of the four rear window FM antennas.

The switchover speed depends on the frequency with which interference occurs. This prevents continuous switching between the antennas in areas where the FM reception is very poor which itself causes reception interference.

Demodulation/digitization of radio remote central locking signals
The demodulator is located in the left antenna amplifier module (A2/64). During demodulation the useful signal (radio remote central locking signal) is generated from the received HF signal and then digitized. The signals processed thus are then forwarded over a separate line, to the rear SAM control unit with fuse and relay module (N10/2).