碩士 / 國立海洋大學 / 電機工程學系 / 88 / The underwater channel is a complex environment with severe interference, thus the implementation of underwater communi-cations is more difficult than that of radio communications. Furthermore, the energy of radio wave decays rapidly when it is propagated in water, therefore the acoustic wave is a better choice for underwater communication.
In this thesis, the pi/4 DQPSK modulation techniques for under-water acoustic(UWA) telemetry modem are investigated.
The direct sequence spread spectrum scheme is also employed to overcome the UWA channel effect.
The TI TMS320C31 DSP set, modulator, demodulator, A/D converter, D/A converter, and UART are used to build up a fundamental hardware architecture for BPSK, QPSK and pi/4 DQPSK transmissions. And we use TI TMS320C3X assembly language and C language to design the processing programs. Real-time ASCII characters, pictures, and images transmission experiments between two PC via UWA channel are conducted in the laboratory.
| Identifer | oai:union.ndltd.org:TW/088NTOU0442007 |
| Date | January 2000 |
| Creators | Chen Yen-Liang, 陳彥良 |
| Contributors | Lu Fu-Sheng, 呂福生 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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