The principle and debugging method of duplexer

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

The principle and debugging method of duplexer

Posted Date: 2024-02-01

A duplexer is a relatively special bidirectional three-terminal filter. The duplexer must not only couple in the weak receiving signal, but also feed the larger transmitting power to the antenna, and both are required to complete their functions without affecting each other. A general duplexer is composed of a spiral vibration cavity. Due to its high operating frequency and large influence on distribution parameters, it is often made into a sealed sleeve. Each signal feeder uses a coaxial cable cavity profile with good shielding effect, and certain requirements are also required. The finish is often black in order to facilitate heat dissipation. The three signal terminals generally use standard high-frequency connectors Q9 or L16 high-frequency sockets. Wireless communication requirements for duplexers.

A duplexer is one that allows us to connect the TX path and RX path to a common antenna without interfering with each other. When the transmitter and receiver frequencies are different, two filters can be combined. One filter is used for receiving and the other is used for transmitting as shown in the picture below.

The filtering method does not work when the transmitter and receiver frequencies are the same. In this case, we use a circultor, which passes the signal in only one direction, as shown below.

Debugging method of duplexer

A duplexer is a device used to transmit and receive signals on the same frequency band. When debugging a duplexer, here are some common methods and steps:

1. Check the hardware connection: Make sure the duplexer is correctly connected to the corresponding sending and receiving equipment, and the connection lines are intact. Verify the stability and correctness of the cable connections.

2. Test equipment inspection: Ensure that the test equipment used (such as power meter, spectrum analyzer, etc.) is working properly and has sufficient accuracy and sensitivity.

3. Initial settings: Follow the instruction manual of the duplexer to perform initial settings. This may include setting the center frequency, bandwidth, gain and other related parameters.

4. Transmit channel test: Use test equipment to send a signal to the transmit end of the duplexer, and check whether it passes through the duplexer correctly and the signal strength and quality are as expected. You can use a power meter or spectrum analyzer to measure the insertion loss and out-of-band leakage of the duplexer.

5. Receive channel test: When no signal is sent, use test equipment to input the signal to the receiving end of the duplexer and check whether it is correctly transmitted to the receiving device. You can use a power meter or spectrum analyzer to measure the isolation of a duplexer.

6. Parameter adjustment: According to the measurement results and requirements, the parameters of the duplexer can be adjusted. For example, gain can be adjusted to optimize the quality and strength of transmitted and received signals.

7. Repeat the test: After adjusting the parameters, repeat the test of the sending and receiving channels to ensure that the adjusted duplexer performance meets expectations.

8. Actual application testing: Connect the debugged duplexer to the sending and receiving equipment in the final application, and conduct actual application testing to ensure that the performance of the duplexer in the actual environment meets the requirements.

Review Editor: Huang Fei

#principle #debugging #method #duplexer