Tetra Digital Trunking Terminal Hardware Design

Presently,as the important part of mobile communication system,special mobile communication develps fast. Digital trunk mobile system is the advanced level of the special mobile communication,and it has attracted attention abroad. Various kinds of digital trunk system stardards came out one by one,and the standards of TETRA and iDEN are the most popular in the world. In our country,the department of information indurstry specify four standards ,including TETRA,iDEN,GOTA and GT800, as the recommended standards.Considering the advantages of TETRA,the integrated mobile communication system of our military will be constructed based on TETRA technology standard. The task is a portion of the pre-reaserch project of the digital trunk system for military.Based on collecting the digital trunk technology stardards of TETRA,this paper analyze the arithmetics used by the digital trunk of TETRA,and make the simulation of the modulation and demodulation arithmetic. Based on the simulation work,we designed the circuit for the terminal of the digital trunk mobile communication system of TETRA, whose was mainly constructed by DSP+FPGA and included voice sampling/reconstructing chip,AD,DA,OP and so on. This circuit can realize the function of encoding/decoding and modulating/demodulating of the digital trunk system of TETRA. After the design of the hardware,we debugged all the modules of the hardware and got the result of the debugging. At last,we realize the real-time voice encoding/decoding over the hardware successfully.