【作者】 余丽敏；

【导师】 程恩；

【作者基本信息】 厦门大学 ， 无线电物理， 2002， 硕士

【摘要】 水声信道是一个极其复杂的随机时间-空间-频率变参信道，存在窄带、高噪、强多途干扰、传输衰耗大等众多因素的制约，是至今难度最大的无线通信信道。水声通信技术也由此成为水声技术领域中一个极其复杂、极具挑战性的研究方向。将传真通信应用于水声领域，是一个比较新的研究课题。本论文对水声传真通信进行了初步的研究与探索。在商业办公领域，传真机(Fax machine)是一种应用广泛、非常实用的电子设备。传真的意义在于多页静止文本页面的传输与精确重现。而水声信道的传真发送除了具备传统的传真发送的意义，还有着其特殊的意义：在信道状况及其恶劣，纯数据通信完全无法实现的情况下，串行图像扫描传输机制的传真发送，以文本重现的方式提供了数据传输的另一个可行方案。本论文初步构造了一个水声传真通信系统。完成了PC传真软件的设计和水声传真Modem的设计。针对水声信道的强多途干扰特性，以及传真文本文件的特殊冗余特性，本论文设计了特殊的传真文件压缩／解压算法和调制／解调方案。在BorlandC++Builder 5． 0平台下，使用其VCL组件和大量win32 API函数完成了水声传真软件的编程，实现了传真文件的无损压缩、解压恢复以及打印控制。论文采用TI公司的高性能DSP芯片TMS320C542作为水声传真Modem的主控芯片，实现数字频率合成调制发送和接收端的Goertzel频谱分析解调。采用TLC320AC01音频级模拟接口芯片实现了DSP与模拟信号的接口。对于DSP同步串口与PC异步串行口之间的通信，本论文设计了专门的DSP算法，使用软件接口，实现了同步串口与异步串口之间的匹配通信。更多还原

【Abstract】 Underwater acoustic channel is a complex time-, space- and frequency-variant channel, which is restricted by numbers of negative factors, e.g. narrow band, high ambient noise, multipath distortion and deep fading. Based on this most difficult wireless channel, underwater acoustic communication therefore becomes one of the most complex and challenging research directions in the field of underwater acoustic technology.Underwater acoustic Fax communication is a new application of using Fax communication into underwater acoustic area. This paper makes a primary exploration into this new application field.Fax machine is a widely-used electronic equipment in offices. The significance of Fax lies in the transmission of multi-page text pages and the accurate reconstruction in receiver. Besides this classic significance of Fax, underwater acoustic Fax communication has its own special significance: Under bad channel conditions, pure data communication is hardly to be implemented. In this case, Fax communication, which is based on the principle of serial image scanning transmission, provides an alternative method of data communication by the way of text reconstruction in receiver.This paper constructs an underwater acoustic Fax communication system and implements the design of PC Fax software and the design of underwater acoustic Fax modem.Taking account of the multipath of underwater acoustic channel and the special redundancy of Fax files, this paper designs special compression/decompression and modulation/demodulation algorithms. The programming of Fax software is realized on the platform of Borland O+ BuilderS.O, with the application of a large amount of VCL components and Win32 API functions.This paper adapts TI’s DSP TMS320C542 as the core of underwater acoustic Fax modem to realize the digital frequency synthesizer, modulation, and Goertzel spectral analysis demodulation. TLC320AC01 is used to realize the interface of DSP and analog signals. As to the communication between DSP’s synchronous serial port and PC’s asynchronous serial port, the paper designs a special DSP algorithm to realize this compatible communication with a software interface.更多还原