Design And Realization Of Underwater Modem Based On QPSK

Underwater acoustic network consists of lots of network nodes deployed in monitoringsea areas. It forms network system by the way of underwater acoustic communication and thenodes perceive and process information in area where network covers. Getting advantages oftime and space information from the nodes, it achieves networked connection of devices andwide cover range in space, and offers effective technical means for widely waters monitoring,real time data acquisition and information exchange.Underwater acoustic network is the inevitable course of merging the water surface andunderwater information situation together to three-dimensional integration informationnetwork. Underwater Modem is the necessary equipment and the key part of the underwatersound net working, and to a great extent it make affects on operating efficiency of theunderwater sound network, overall power consumption and deploying strategy. There ismature commercial underwater Modem abroad at present, for example, American Datasonicsand ATM serials of Bethos. While the development of independent underwater Modemmodule is still in its infancy at home, some research institute only purchase foreign offeringsto do underwater network research, and it is restricted within technology.This paper discussed underwater Modem system design, which based on QuadraturePhase Shift Keying modulation and demodulation algorithm of spread spectrumcommunication technology. The Modem system used low power consumption adsp-bf533chips as the core, adopted QPSK modulation and demodulation algorithm of spread frequencycommunication, This product can realize long distance and long term reliable underwater datacommunication. Underwater Modem connects PC terminals through standard RS-232communication interface for data transmission between underwater devices and terminals.This product with low power consumption, high-integrated, software transplanted and strongof anti-interference advantage, etc. meet the future design direction of underwatercommunication. The Modem system conform to criterion of design demand though testing onthe sea.