The Research And Realization On Digital Modulation Of Software Radio Based On DSP Technology

In recent decades, mobile communication has entered a period of rapid development, it is closely related to people's daily lives and has become a necessity in people's lives, the current mobile communication is in the second generation to third generation of the phase transition.The modulation is a key technology in mobile communication, and it is important for mobile communication to select an appropriate and high effective modulation mode according to different wireless channel characteristic. The appearance of the software radio is a huge impetus to the development of mobile. Constructing a generic, standard, modular hardware platform and realizing the radio function by software instead of hardware can enhance the system flexibility greatly. It is flexible for the digital modulation by software, and it may realize different modulation mode through the airborne to be downloaded and therefore it suits the different communication systems.After reading massive domestic and foreign literature about digital modulation and software radio, In the paper, deeply studying the principles of digital modulation methods as well as the advantages and disadvantages, I designed a software radio platform in order to achieve the corresponding digital modulation. The platform fot TI's DSP chip TMS320VC5416 as the core to process signal for realizing digital modulation algorithms, respectively,the ADC and DAC constitute data acquisition modules and to the modulation signal processing module in the peripheral circuits,and the CPLD constitute logic control module, which provide interface control signals,and realize input information retrieval functions, decoding functions and sub-band function. In software design, it is divided into logic control and digital modulation algorithm in two parts. Part of the overall logic control realize CPLD logic control module and digital modulation part realize ASK, FSK, QPSK modulation algorithm in the DSP module.The software-defined radio platform has lots of advantages such as faster processing speed, real-time operational, large amounts of data storage and so on.