GF82.62-P-0001R Antenna System (ATS), Function
GF82.62-P-0001R Antenna System (ATS), Function
Preliminary remarks
The following describes the antenna system for audio (code 750), TV (code 860), telephone (code 388), navigation, central locking (code 466), TELE AID (code 855) and E-call emergency call system (code 349).
General information
The different antennas are matched in terms of design to their specific reception and transmitting ranges.There are active and passive antennas. The antennas can be designed as transmitter, receiver or as transmitter-receiver antennas. The antennas transmit or receive, e.g. data and voice output information through conversion of electromagnetic radio waves into high-frequency electrical voltages and vice versa.
Active antennas have a DC voltage provided for the integrated amplifier. The voltage supply is set up through separate lines or by means of signal transfer over the given coaxial lines (phantom supply). The GPS antenna (A2/23) as fitted is an active antenna.
Passive antennas do not require a voltage supply. Installed passive antennas are:
^ Windshield antennas
^ Rear window antenna
^ Rear shelf antenna (A27/68)
^ telephone antenna (A2/22)
^ TELE AID substitute antenna (A2/50)
Both the passive and active antennas can be designed as transmitter/receiving antennas.
Transmitter/receiving antennas are:
^ telephone antenna (A2/22)
^ TELE AID substitute antenna (A2/50)
Receiving antennas are:
^ Windshield antennas
^ Rear window antenna
^ Rear shelf antenna (A27/68)
^ GPS antenna (A2/23)
The Keyless Go antenna system (code 889) and the antenna system for the tire pressure monitor (code 475) are described in separate documents.
Antenna system block diagram
Displayed for the following equipments:
^ COMAND operating and display system (code 352)
^ Radio (code 750)
^ D-network portable CTEL telephone (D2B) (code 317)
^ Tele Aid (Code 855)
^ E-Call emergency call system (code 349)
^ Stationary heater (code 228)
Description of block diagram for antenna system
The AM signal of the rear window antenna (4) is sent over the rear window antenna amplifier module (A2/12) to the antenna switch (3). The AM signal received at the rear shelf antenna (A2/68) is also sent over the rear shelf antenna amplifier (A2/67) to the antenna switch (3). The antenna switch (3) is integrated into the rear shelf antenna amplifier A2/67.
The antenna switch (3) switches, depending on the Vario roof position, either the AM signal of the rear shelf antenna (Vario roof closed) or the AM signal of the rear shelf antenna (A2/68) (Vario roof open) to the left antenna amplifier module (A2/64).
The switching signal for the antenna switch (3) (Vario roof open or closed) comes from the RSC control unit (N52) over the CAN bus to the radio (A2) or to the COMAND operating, display and control unit (A40/3).
The antenna control line (2) of the radio (A2) or of the COMAND operating, display and control unit (A40/3) is used to actuate the antenna switch (3) in the rear shelf antenna amplifier (A2/67) using a voltage depending on the roof position.
The FM and TV signals received by the windshield antenna (5) on the left-hand side are sent to the left antenna amplifier module (A2/64). The FM, TV and radio remote control locking signals received by the windshield antenna (5) on the right-hand side are sent to the right antenna amplifier module (A2/65).
In the right antenna amplifier module (A2/65) FM, TV and RRCL signals are filtered and amplified. TV signals are sent to the COMAND operating, display and control unit (A40/3), the FM signals (FM3, FM4) to the left antenna amplifier module (A2/64). The RRCL signal is demodulated in the right antenna amplifier module (A2/65), digitized and sent via a data output to the overhead control panel (N70).
In the left antenna amplifier module (A2/64) FM and TV signals are filtered and amplified. The TV signals are sent to the COMAND operating, display and control unit (A40/3). The strongest of the 4 FM signals (FM1 up to FM4) is selected and sent to the COMAND operating, display and control unit (A40/3) or the radio (A2). The AM signal from the antenna switch (3) is filtered and also sent to the COMAND operating, display and control unit (A40/3) or the radio (A2).
The signals received by the GPS antenna (A2/23) are sent over the antenna splitter (A2/5) to the COMAND operating, display and control unit (A40/3) and the transmitter/receiver and TELE AID, D2B (A35/17) or the E-call control unit (A35/8) for further processing.
The telephone antenna (A2/22) is used to send and receive telephone signals, TELE AID signals (as long as reception is not poor) and stationary heater system signals. The signals are sent over the telephone/portable CTEL/STH radio remote control antenna splitter (A2/53) of the corresponding component. The telephone interface (A34/4) is used to connect the portable CTEL (34/6) to the antenna system.
The telephone interface control unit (A34/4) and transmitter/ receiver control unit and TELE AID control unit, D2B (A35/17) or E-call control unit (A35/8) as well as the radio (A2) or COMAND operating, display and control unit (A40/3) are connected via the Digital Data Bus (D2B).
If reception over the telephone antenna (A2/22) is poor, then the signals received by the TELE AID backup antenna (A2/50), are sent to the telephone transmitter/receiver and TELE AID, D2B (A35/17) or the E-call control unit (A35/8), the transmission path is inverted.
The signal for the STH radio remote control transmitter (A8/3), which is received over the antenna A2/22, is sent to the radio remote control receiver (A6/1). With modification year 2004/1 a signal received from the STH radio remote control transmitter (A8/3) is acknowledged by the receiver unit for the radio remote control (A6/1) by sending a radio signal to the STH radio remote control (A8/3).
In vehicles without stationary heater the telephone/portable CTEL/STH radio remote control antenna splitter (A2/53) is not installed.
If the telephone transmitter/receiver and TELE AID, D2B (A35/17) are installed, the telephone interface (A34/4) is not applicable.
In vehicles designated for the USA (code 494a) and Japan (code 498) both the E-call control unit (A35/8) and the telephone interface (A34/4)are installed. There is then no connection between the E-call control unit (A35/8) and the telephone/portable CTEL/STH radio remote control antenna splitter (A2/53).
