CLM920_NC3_LTE Module hardware manual
Shanghai Yuge Information Technology co., LTD
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3.17.1 Main antenna interface
CLM920 NC3's 49-pin main set antenna interface, in order to facilitate antenna
debugging, it is necessary to add
π
-type matching circuit on the main board, take 50-ohm
impedance line, the recommended circuit is as follows
：
Figure 3-25 Main antenna matching circuit
3.17.2 Diversity antenna interface
CLM920 NC3's 35-pin is a diversity antenna interface. To facilitate antenna debugging,
it is necessary to add a
π
-type matching circuit to the main board, and take a 50-ohm
impedance line. The main antenna and the diversity antenna need to maintain a certain
spacing. The recommended circuit is as shown below
：
Figure 3-26 Diversity Antenna Matching Circuit
3.17.3 GNSS interface
CLM920 NC3's 47 feet are GNSS antenna interfaces, support GPS, BEIDOU,
GLONASS, GALILEO signal reception. If you need to use it, you need to open the GPS with
AT command AT+CGPS=1 (please consult CLM920 NC3 AT command set manual for details)
In order to facilitate the debugging of the antenna, it is necessary to add a
π
-type matching
circuit to the main board, and take a 50-ohm impedance line. The GNSS antenna needs to