Research Of Baseband Transmitter Based On DSP

In wireless communication systems, the traditional radio transmitter relies more on hardware, whose expansibility is poor, it is very difficult to satisfy the complex changeable application environment. The SR (Software Radio) transmitter can satisfy the different environment and demands of the users through the reshuffle application software, which has the very big flexibility. Because of their high operation speed, programmable, interfaced easily. Digital Signal Processor (DSP) is applied mostly in real time signal processing. Using DSP to implement digital signal processing has become the current development trend. At present, SR transmitter based on DSP which satisfy the complex changeable application environment is the most prevalent and effective solution.With digital signal process as the core and modern communication theory as its foundation, the thesis researches the problem of SR Baseband transmitter and designs the hardware platform of a SR Baseband transmitter as well. Firstly, it elaborates the sampling theory and multi-velocity sampling theory, which possess theoretical guidance for the design and implementation of a SR Baseband transmitter. Secondly, the orthogonal transform—Hilbert transform is introduced in theory detailedly. The Hilbert Filter is an entirely passed filter giving 90 degree phase shift to the input signal. After passing the Hilbert Filter, range of the signal spectrum has no change and has 90-degree phase change, which is an important part of the software radio and is widely applied in digital filter, modulation and demodulation of the digital signal and frequency conversion. It also introduces the theoretical diagram of Baseband transmitter and design process of each module of Baseband transmitter system in detail. Finally, SR Baseband transmitter system has been achieved according to the development board DSK6713 based on TMS320C6713 DSP of Texas Instruments Corporation, which has been achieved the goal of Single Side Band (SSB) of different baseband modulation signals. Meanwhile, the result of experiment is analyzed and compared in order to demonstrate performance of Baseband transmitter system. The comparison between theoretical analysis and experiment results proves the correctness of the design work, and the system performs well. The performance index of transmitter system has been satisfied all design requirements. Furthermore, it can be performed with low cost and easy operation comparing with other congeneric products.The code of Baseband transmitter system is written according to software radio thought, which is reused and transplantable in good coding style. It has been proved that this system has good characteristics of maintainability, reliability and adaptability, the parameters of the system is changed flexibly. The product of the thesis could be used widely in radio communication systems.