Design And Implementation Of The Embedded Underwater Acoustic MODEM Signal Processing Board

In the underwater acoustic (UWA) communications field, Orthogonal frequency division multiplexing (OFDM) obtains the more and more many person's favor by its superior performance. A set of embedded submarine MODEM signal processing board has been designed in this article. The main content of this thesis are as follows:First,the OFDM basic principle is studied. An realization method of OFDM system applied for UWA communication was proposed. According to the realization method of OFDM system, An concrete hardware electric circuit realization plan has been designed, including the systems control module, the signal processing module, the analog signal transmitter and receiver modules as well as the way to communicate and to monitor. In design process,full consideration of submarine equipment power supply question, many kinds of way to communicate and to monitor was designed, to reduce the power consumption and to adapt to different environments, to satisfy on the requirements of the communications rate.Second, The TMS320VC5509A USB module has been developed.The USB1.1 specification has been analyzed,based on which the USB firmware procedure has been developed using DSP CSL, The USB device driver as well as the application procedure frame has been developed using WinDriver, Through testing, USB devices can be stability.Last, The embedded Ethernet Interface has been developed. The TCP/IP protocal has been analyzed, and a full light embedded TCP/IP stack- LwIP was selected. To bring into fullplay of the protocol stack performance,a RTOSμC/OS-Ⅱwas introduced.A detail introduction of portingμC/OS-Ⅱon TMS320VC5509A has been done, Practice has proved that the system is stable and reliable. A introduction of porting LwIP onμC/OS-Ⅱhas also been done. The ethernet controller LAN91C111 hardware driver has been developed. Finally the performance of the driver and protocol stack was tested.