User's Manual

DRAFT
4: VAM-CM interfaces
4.2.8.1:Signal conditions
The Control and ID interface is equipped with level shifter in VAM-CM board. This solution enables
VAM to adjust I/O voltage system by applying own V_io voltage to VAM control interface connector.
For more details, see Power Supply interface description on page 16.
Power on/off is not controlled via level shifter. Power on/off is pull down type control having internal
pull-up resistor for "HIGH-state" implemented in VAM-CM board. Power on/off action is achieved by
pulling this line to GND so no level shifting is needed. Power on/off line shall be floating when
inactive, no external pull-up is allowed.
4.3: Radio interface description
4.3.1:GMR2 transceiver antenna interface
Dedicated antenna interface for GMR2 transceiver. The antenna interface uses snap on SMB
connector JAE SMB003D00 to provide cost efficient and robust interfacing for RF signal. Figure 9
shows the connector used for GMR2 RF transceiver antenna interface.
Figure 9. GMR2 transceiver antenna interface connector
Signals in GMR2 transceiver antenna interface are connected as shown in Table 10 .
Pin Signal Description
Center GMR RF Frequency: 1518 MHz – 1675 MHz
Power:
output +33,5 dBm MAX
input-10dBm MAX
Frame GND Signal GND
Table 10. GMR2 transceiver antenna interface pins
4.3.1.1:External antenna requirements.
External GMR antenna shall meet following baseline requirements (RF cable losses not included in
antenna gain figures). It shall be noted that actual antenna performance requirements are
dependent on terminal type (fixed, maritime etc). Detailed antenna requirements may be provided
by Inmarsat on request.
min max Unit
Frequency band 1518 1675 MHz
18:GSPS Core Module 2.0 VAM-CM HW Description
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