Antenna system (ATS), function - GF82.62-P-0001SXU
MODEL 221 with CODE (494) USA version up to Model Year 08
Preliminary remarks
The following description deals with the antenna systems for
- COMAND APS USA (with navigation) (code 530),
- SIRIUS satellite radio (code 536),
- Sound system (code 810),
- Preinstallation for telephone "Handy", UPCI system, USA/Canada (code 387),
- TELE AID emergency call system (code 359),
- Radio remote control with panic switch (code 763) and
- Keyless Go (code 889)
are described in the following.
General information
The various antennas are designed according to their special reception and transmission ranges. There are active and passive antennas. The antennas can be designed as transmission, reception or as transmission/reception antennas. The antennas transmit or receive voice information by converting electromagnetic radio waves into an electric voltage and vice versa.
Passive antennas
Passive antennas do not require a power supply.
Active antennas
Active antennas are supplied with power and have an integrated amplifier. The voltage supply can be provided on separate lines or via a coaxial cable (phantom feed). The actual signal is transmitted via this coaxial cable.
Transmit/receive antennas
The transmission/reception antennas are
- the telephone antenna (A2/49a1) in the telephone and GPS roof antenna (A2/49),
- the Bluetooth antenna (A2/91),
- the emergency call antenna (A2/52),
- the emergency call system left backup antenna (A2/54) and
- the emergency call system right backup antenna (A2/55).
Reception antennas
Receive antennas are
- the AM antenna in the rear window,
- the FM1 to FM4 antennas in the rear window,
- the SDAR antenna (A2/82),
- the radio remote central locking antenna in the rear window and
- the GPS antenna (A2/49a2) in the telephone and GPS roof antenna.
The Keyless Go antenna system (code 889) is described in separate documentation. In vehicles with Keyless Go the authorization signal is received by the radio remote central locking antenna.
Location of components
Block diagram of antenna systems
Description, block diagram of antenna system
The rear window FM1 to FM4 and AM antenna signals are picked up, filtered and amplified by the rear window antenna amplifier module. A diversity processor in the rear window antenna amplifier module selects the strongest signal from the FM antenna signals and relays it to the audio tuner control unit. The AM signal is also relayed to the audio tuner control unit.
A phantom voltage (DC offset) is used to switch between AM and FM. If a direct voltage of 0 volts is present at the intermediate frequency input of the rear window antenna amplifier module, it operates in AM mode. If a direct voltage of 12 volts is present at the intermediate frequency input of the rear window antenna amplifier module, it operates in FM diversity mode.
Depending on the vehicle's location, the satellite signal or the terrestrial signal is transmitted by the SDAR antenna (Satellite Digital Audio Radio (satellite radio)). Outside of cities, the terrestrial signal is usually used. The SDAR antenna is integrated in the emergency call antenna.
The signals that are prepared by the SDAR control unit are relayed to the audio tuner control unit via the MOST (Media Oriented System Transport) digital data bus.
The signals of the radio remote central locking antenna in the rear window are picked up by the rear window antenna amplifier module. Processing of the signal depends on the vehicle equipment.
The radio remote central locking signal of the antenna is switched to a radio remote central locking receiver in the rear window antenna amplifier module, demodulated and directly transmitted to the rear SAM control unit with fuse and relay module for further processing.
For vehicles without Keyless Go (code 889), a phantom voltage (DC offset) of 0 volts is applied at the Keyless Go input of the rear window antenna amplifier module.
If the vehicle is equipped with Keyless Go, a phantom voltage of 5 volts is present at the Keyless Go input of the rear window antenna amplifier module. The radio remote central locking signal with the Keyless Go authorization signal is switched to the Keyless Go outlet and directly relayed to the Keyless Go control unit. The radio remote central locking signal and the Keyless Go authorization signal are evaluated in the Keyless Go control unit.
The signals from the GPS antenna reach the antenna splitter. The signals are relayed by the antenna splitter to the COMAND control unit and the emergency call system control unit. There, the signals are required for location finding.
The telephone signals are transmitted and received by the telephone antenna. This is connected to the portable CTEL via the portable CTEL antenna amplifier and the UPCI [UHI] portable CTEL holder (Universal Portable CTEL Interface).
The UPCI portable CTEL holder (Universal portable CTEL Interface) is connected to the UPCI (Universal portable CTEL Interface) control unit together with the portable CTEL via the data and control lines. This is connected to the COMAND control unit via the MOST bus.
The signals received by the GPS antenna are transferred to the GPS antenna splitter.
The signals are relayed by the GPS antenna splitter to the COMAND control unit and the emergency call system control unit. There, the signals are required for location finding.
The emergency call system control unit operates in the same manner as a telephone. If the emergency call system is active, it transmits and receives signals via the emergency call antenna.
In the event of interruptions when transmitting and receiving via the emergency call antenna, the emergency call system left backup antenna and the emergency call system right backup antenna are used for transmitting and receiving.
The emergency call system antenna splitter adds and splits the signals from the/for the emergency call system backup antennas.
If the TELE AID emergency call system is active, other audio systems and the portable CTEL are muted if they are switched on.
External equipment can communicate with the Universal Portable CTEL Interface (UPCI [UHI]) control unit via the Bluetooth antenna. Signals can be transmitted to or received from the external equipment.
| Rear window antenna component description | GF82.62-P-3123SX | ||
| GPS antenna splitter, component description | GF82.62-P-3129SXU | ||
| Rear window antenna module component description | GF82.62-P-3131SXU | ||
| Telephone and GPS roof antenna component description | GF82.62-P-4119SX | ||
| Bluetooth antenna component description | GF82.62-P-4201SX | ||
| Portable CTEL antenna amplifier component description | CODE (387) Preinstallation for telephone "Handy", UPCI system, USA/Canada | GF82.70-P-3111SXU | |
| Emergency call antenna component description | GF82.95-P-4000SXU | ||
| Emergency call antenna splitter component description | GF82.95-P-4001SXU | ||
| Emergency call system backup antennas component description | GF82.95-P-4002SXU |