Design And Implementation Of Audio And Transmission Driver On Handheld Software Defined Radio Platform

Audio data collection and data transmission are two important functions of the handheld software defined radio platform, these two functions are the foundation of real-time voice communication of handheld software defined radio platform. How to implement data collection and transmission is an important issue to be considered for developing handheld software radio platform real-time voice communication.To achieve the above two functions, the following issues need to be solved:analyze audio driver architecture of Linux,implement the underlying driver, improve the portability and ease of use; simplify data transfer protocol,reduce the difficulty of development, design data transmission channel between ARM and FPGA.Therefore, considering the practical application of the small form factor software defined radio platform, this paper implements the audio data collection function and data transmission function of GPP and FPGA based on the handheld software defined radio platform which is equipped with Android operating system. This paper’s research includes the following aspects:Firstly, implement ALSA’s driver in Linux audio subsystem. This paper researches the architecture of ALSA and how to use the related chips,and achieve the ALSA driver including the audio chip driver、MCBSP driver、DMA driver, as a result, the platform has the ability to record and play audio signal.Secondly, build a data transmission channel between ARM and FPGA. Complete the FPGA clock configuration and FPGA program loading, set up basic environment for the FPGA. The data transmission driver is based on the GPMC module which is integrated in the DM3730, this driver can achieve bidirectional data transmission between ARM and FPGA and build an inter-processor data transfer channel.Thirdly, complete the application layer program. The application layer program can implement the function of recording and playing audio signal; then, the audio data will be compressed by the DSP which is integrated in the DM3730; eventually, the application layer program calls the interface of data transmission driver to send data to the FPGA chip.Lastly, this paper verifies the audio driver and data transmission driver. The test results show that the application layer program can call the interface of driver to realize the function of recording and playing audio signal, audio distortion is less than 0.3%, the audio driver works properly; the data transmission driver can realize bidirectional data transmission function, the transmission clock can be up to 70 MHz, the interface of data transmission driver works properly.The thesis content provides scheme for handheld software defined radio platform audio signal record and data transmission, the handheld software defined radio platform based on the scheme has certain advantages in certain situations, and has practical value.