Chaotic Modulation Techniques In The Covert Communication System For Underwater Acoustic Research

The communication technology is the lifeline of the economy and military affairs in world all the time, the secure communication technology is the core. Underwater acoustic communications(UWA) are made difficult by the combined effect of muitipath propagation and high temporal and spatial variability of the channel conditions. The fading which was caused by muitipath propagation was one of the main factors influencing the performance of underwater acoustic communication systems.Firstly some development of chaotic secure communication and chaotic modulation are introduced. Then introducing the characteristic of the underwater channel. After that expounding the theory of the Chaotic-Pulse-Position modulation technology and simulating the system to confirm the parameters. Based on that, bringing forward the Chaotic-Synchronization-Chaotic-Pulse-Position modulation (CS-CPPM), proving the method by the simulating experiment of the Chuas circuit and all the system. Subsequently introducing the synchronization methods for communication with chaos over band-limited channels simply and using the Simulink simulate the model base on the low-pass sixth-order Chebyshev filter. Finally, realizing the CPPM system using FPGA.