Synchronization Module Description
Author
lzm
Date Published
1. Synchronization Features
Supports manual or automatic configuration of TDD uplink/downlink (UL/DL) time slot ratio and special subframe ratio.
Uses a domestically produced 32‑bit CPU with abundant resources, strong computing power, controllable cost, and good product expandability.
Provides GPIO and an indicator LED for synchronization status.
After synchronization is achieved, parameters can be read and written in real time via the serial port.
Supports ECS (Enhanced Cell Synchronization) function.
2. Pin Definition
Name | Pin | I/O | Description | Level |
|---|---|---|---|---|
RFin | 2 | I | NR / TD‑LTE RF signal input, 50Ω input impedance. Synchronization sensitivity may degrade when signal level < -48 dBm or > +5 dBm. Recommended signal level range: -40 dBm to +2 dBm. | ≥ -48 dBm |
RF GND | 1, 3 | GND | RF ground | – |
DETout | 4 | O | RFin input signal detection, amplified and output by the module | TTL 3.3V |
TXD | 5 | O | Module serial port transmit | TTL 3.3V |
GND | 6 | I | Serial port ground | TTL 3.3V |
RXD | 7 | I | Module serial port receive | TTL 3.3V |
VCC | 8 | VCC | 5V power supply | 5V |
GND | 9 | GND | Power ground | – |
ATT_UPLE / UP_TEST_MODE | 10 | I/O | 1. Uplink test mode | TTL 3.3V |
ATT_DLLE / DP_TEST_MODE | 11 | I/O | 1. Downlink test mode | TTL 3.3V |
UL_OUT | 12 | O | Uplink synchronization signal output | TTL 3.3V |
DL_OUT | 13 | O | Downlink synchronization signal output | TTL 3.3V |
TDD_STAT_LED | 14 | O | Synchronization status LED. High level when TDD‑LTE is synchronized. Can directly drive an LED with a current‑limiting resistor > 1 kΩ. | TTL 3.3V |
UP_AD | 15 | I | Reserved | – |
ATT_CLK | 16 | O | Shared clock output for uplink/downlink digital attenuators | TTL 3.3V |
ATT_DATA | 17 | O | Shared data output for uplink/downlink digital attenuators | TTL 3.3V |
TEST_Key | 18 | – | Spare; can be connected directly to GND | – |
3. Product Images
(Images omitted)
4. Serial Protocol & Debug Interface
The serial port currently uses the China Mobile repeater network management protocol. Custom protocols are also available. Via the module's serial port, related parameters such as power, attenuation (ATT), calibration power, and test mode entry can be read and set. Synchronization parameters are advanced development parameters and are generally not exposed to users. The interface is shown below:
(Interface image omitted)
6. Usage Precautions
A SAW filter must be added at the RF input of the module, supporting 4G bands and N41.
If the module is required to control the attenuator (ATT), use digital attenuator model ARW621A.