Research On Coding Of Ultrasonic Underwater Communication

Along with the human resources development of the earth gradually turning tothe ocean, solving the Marine underwater communication becomes more and moreurgent. Because of the electromagnetic wave as the carrier’s traditional land and aircommunication will be absorbed by the sea water in underwater communication, thecommunication distance can hardly reach people’s need. To solve the tool of movingunderwater communication such as underwater submarines,"The dragon" and so on,which makes the domestic and foreign research on underwater communicationproblems began. In this background, this paper is aimed at studying how to improvethe quality of the underwater communication anti-interference ability.The paper’s study includes the following content: the first one, analyzed thedomestic and foreign research underwater communication status, and got theconclusion that traditional communication which spread by the electromagnetic wavedid not apply to underwater communication, analyzed the phenomenon that the wayof transmission by ultrasonic instead of the electromagnetic wave way was easilysuffered interference. The second one, studied the work mechanism of ultrasonictransducer, discussed how to solve the interference, and compared the characteristicsof2ASK,2FSK,2PSK modulation technology during ultrasonic transmission.Based on this study, then put forward improving the anti-interference abilitythrough the encoding technology, through different pseudo random sequence ofdiscussion, selected the m series as ultrasonic coding sequence, and did the simulationunder the MATLAB environment. Finally, tested and verified the results of the abovetheory study and software programming, including the design of ultrasonic signalsdrive circuit, the design of the ultrasonic signal amplifier circuit, the design of carriersignal’s generation which based on FPGA, and the hardware design of m sequencegenerator’s control circuit, coding circuit. The software design used the ISE development environment, and in the FPGA chip used Verilog HDL hardwaredescription language to do the correlation function design and simulation. The testshowed that the theoretical research of the related results corresponded with functionof practical circuit. This paper’s study can provide some reference for furtherunderwater communication technology research.