The Development Of Communication Transmission Stytem By Coupling On Mooring Chain For Marine Monitoring

A new type of communication technology for ocean monitoring system is researched and presented in this paper, which was based on Inductively Coupled Communication(ICC) technology on mooring chain, to achieved the data transmisstion between the buoy and underwater sensors. Compared to the large volume, high-power, high-cost underwater acoustic communication system which was used widely, this communication system based on a simple plastic coated cable as the transmission medium has the advantage of small size, low power and low-cost, and which can be applied in underwater communication networks over long distances. Never the less, because of its special mount way to a plastic coated cable, it can be loaded and unloaded simply, flexibly, safely. If one node is damaged, the communication would not be interrupted. This technology is valuable when long distance real-time data transmission was necessary for data aquisition from multiple sensor on any position of the vertical profile.This paper describes the theory of the communication transmission system by Coupling on mooring chain. And introduces the hardware design and software design of the system, which focuses on the DPSK modulation and demodulation design based on CPLD、hardware and software design for de-noising and the communication protocol.The all system can be described as three parts as follows:1Send and receiver circuit. The CPLD, with peripheral transmission circuit、amplifier circuit、 filter circui、analog-digital conversion circuit are designed as DPSK modulation and demodulation for the weak signal, Including hardware and software design for noise removal.2Signal coupling loop. includes enameled wire and the ring separation ferrite. It is made by wind enameled wire on the ring separation ferrite to a certain number of turns, and is used for coupling output after the DPSK modulation.3Communication control circuit. According to the requirements of low-power for underwater system, the MSP430is used to implement a communication protocol between each underwater node, which is for screening the received data, excluding the garbled Produced by noise.The communication transmission system by Coupling on mooring chain had been tested in the laboratory by joining a resistance or in the simulating seawater. Also it had been tested in the sea. Through these tests, it shows that the system designed reliably, communicate well, can used for long-distance, multi-sensor real-time data transfer, it has a high commercial value to promote.