User's Manual

Smart Machine Smart Decision
SIM7100A_User Manual_V1.01 2014-12-11
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Figure 35: Active antenna circuit
Figure 36: Passive antenna circuit (Default)
In above figures, the components C1 and L1, L2 are used for antenna matching, the values of the
components can only be obtained after the antenna tuning usually, and they are provided by antenna
vendor.C2 in Figure 35 is used for DC isolation. In active antenna circuit, users must use an external
LDO/DCDC to provide VDD voltage whose value should be taken according active antenna characteristic,
and VDD can be shut down to avoid consuming additional current when not being used.
GNSS can be used by NMEA port. User can select NMEA as output through UART or USB. NMEA
sentences are automatic and no command is provided. NMEA sentences include GSV, GGA, RMC, GSA,
and VTG. Before using GNSS, user should configure SIM7100A in proper operating mode by AT
command. Please refer to related document for details. SIM7100A can also get position location
information through AT directly.