CLM920_AC3 Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
- 37 -
converter interface 1
resolution12bits
45
ADC0
Analog to digital
converter interface 0
0.3
1.3V
ADC resolution
12bits
3.14 RF interface
The CLM920 AC3 module provides two antenna interfaces, one main set antenna
interface, which is responsible for the 4G and 3G signals of the transceiver module, and one
diversity antenna interface. It is responsible for receiving 4G and 3G signals. The signal
degradation caused by multi-path and high-speed movement can be passed. Adding a
diversity antenna enhances the signal. The impedance of the two antenna interfaces is 50
ohms. 4G recommends connecting diversity antennas to limit high-speed movement and
signal degradation caused by multipath.
Table 3-24 Antenna interface pin definition
Pin
Name
I/O
Description
Remarks
49
ANT_MAIN
IO
Main antenna interface
50 ohm characteristic
impedance
35
ANT_DIV
AI
Diversity antenna interface 50 ohm characteristic
impedance
3.14.1 Antenna matching circuit
The 49-pin of the CLM920 AC3 is the main set antenna interface. To facilitate the
debugging of the antenna, a
π
-type matching circuit needs to be added to the main board,
and the 50-ohm impedance line is taken.
The 35-pin of the CLM920 AC3 is a diversity antenna interface. To facilitate antenna
debugging, a
π
-type matching circuit needs to be added to the motherboard, and a 50-ohm
impedance line is taken.
Recommended circuit as shown below
：
