The Design, Based On Adsl Technology, An Artillery Communication Modem

This thesis originates from a practical engineering project, which belongs to the Digital Signal Process(DSP) technology application in the signal communication category. The main task of this project is to design a special line Modem card, which will be one part of real-time system, using the ADSL(Asymmetric Digital Subscriber Line) technology. It is an attempt to reconstruct the civilian technique for military purpose. Although ADSL technology is now very mature, it remains quite a problem to apply it in the special line communication system, both hardware and software structure require a degree of transformation. Our design abandon the normal structure of combining MCU,DSP and AFE(Analog Front End)together in one card but apply only one DSP chip to achieve modulation functions.Firstly, we analy the characteristics of existing copper line communication technology and describe the use of DMT(Discrete multi-tone) modulation and demodulation technical reasons. Then we devide Modem into three basic modules in functional terms, estimation of the DSP chip has also been calculated, so at least the program is feasible form the calculation speed considerations. In this paper we mainly discuss the hardware design and DMT algorithm research. Hadware design includes communication interfaces to PC, peripheral circuit of the DSP chip and the AFE, LineDriver and Hybrid module, also the voice separtator. The software based on the design of the system over roll structure, it focus on FFT,IFFT and water-pouring theorem. Matlab is used to simulate how the algorithm works.