Research of deep sea disposable profile channel modeling

XCTD is the abbreviation of the Expendable Conductivity-Temperature-Depth profiler. As one of typical products of the deep-sea abandoned profiler, it had been developed successfully and rapidly in recent years. Considering the influence of cost, work environment or other factors, the transmission line uses a double-stranded enameled wire to transmit data signal in XCTD measurement system. Because of the constraint of the real-time change of channel impedance parameters and the interference of complex ocean noise, the measured data can not transfer to receiving terminal effectively. So how can we make sure that the data signal reliably transfers in the channel at high transmission frequency is one of the key problems of the development of XCTD technology. Firstly, the paper analyzes the transmission characteristic of XCTD channel by establishing the optimized circuit model of XCTD channel, then, the XCTD channel lab model is built to simulate the data transmission process of XCTD underwater measurement. And according to the frequency sweeping method, the LABVIEW platform and data acquisition card is used to get the channel amplitude frequency and phase frequency characteristics at fixed depth. Finally, the three spline interpolation algorithm is used to fit the channel transfer function, and the transmission characteristics of the channel are optimized. It provides a new solution for the research of channel characteristics and the accurate transmission of data.