中文摘要：

由于海洋中恶劣传输条件的影响，采用一种调制解调技术往往难以同时实现高数据传输率、大传输距离以及良好的信道适应性．为适应不同信道下的通信要求，利用直接序列扩频技术（DSSS）和正交频分复用技术（OFDM）设计并实现了基于TMS320C6713 DSP芯片的双模水声通信系统，给出了DSSS和OFDM通信参数设定以及模式转换协议设计．海上实验结果验证了该系统的有效性．

英文摘要：

Underwater acoustic communication channels are generally characterized as time-variant dispersive channels,which are also doubly spread channels in time and frequency. Currently there isn＇t any single communication technique that can work well under different type of channels. A dual mode System is presented in this paper,which incorporate the DSSS and the OFDM technology to develop a channel-robust solution. The system implemented on TMS320C6713 TI DSP platform contains the design of modulation, de modulation and mode switch protocol. The communication technical parameters and the switch protocol are introduced. Experimental results obtained in a physical shallow water channel demonstrate the effectiveness of the proposed system.