The duplexer  is a heterogeneous dual -e -radio station. The main accessories of the relay platform are to separate the launch from the receiving signal to ensure that both receiving and launch can work normally at the same time. It is composed of two sets of band -blocking filters of different frequencies to avoid transmission of signal transmitting signals to the receiver.

     In the wireless mobile phone communication system, the main function of the railor is to combine the signal of the input multiminomotical band to the output path to the same set of indoor distribution systems.

     The principles and design methods of the frequency selection of frequency selection and dual -device are consistent. They are combinations of different frequency band filters, but the two are slightly different: the dual device works on the same frequency band of the communication system. Two two. The public port of the filter is connected to an antenna, one of which is selected by the frequency of the filter in the upward frequency band. In the future, the signal of the antenna will be sent to the antenna emitting. The frequency selection function of the dual device and the rail also inhibits the mutual interference between each sender.