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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/28697

Title: 應用TMS320C6X DSK研製全數位水下傳呼機
Authors: 呂福生;曾敬翔;吳鑌崇
Contributors: NTOU:Department of Electrical Engineering
Date: 2006-03
Issue Date: 2011-10-21T02:39:20Z
Publisher: 第八屆水下技術研討會論文集
Abstract: 摘要:本文探討應用數位信號處理模組實現全數位多感測器水下傳呼機之雛形。收發系統以直序式展頻通訊技術為核心,應用匹配濾波器與非同調延遲追蹤鎖相迴路,達成展頻瑪的擷取語同步。傳統的延遲鎖相迴路,如果以數位處理器實現,頗為困難。本文提出一修正的延遲鎖相迴路,已暫存器儲存需適當位移的輸入訊號,即可達成相當於移動展頻瑪訊號的功效,此修正的延遲鎖相回容易實現及操控,而其效果與傳統架構者完全相同。所研製的系統採用較短的展頻碼以維持適當傳輸率,但當傳輸距離增長,導致多重路徑干擾更嚴重時,則利用多感測器接收技術,藉由等增益結合方法與直接決策-決策迴授等化器改進接收功能。除了電腦模擬及離線發收分析外,亦利用實驗水槽進行即時水下數據傳輸,測試資料包括文字檔及簡單圖形。電腦模擬及水槽實驗結果顯示,所研製的全數位水下傳呼機已能順利達成圖文傳輸的預期目標。
Abstract:The TMS320C6711 DSK module is used to build an all-digital multi-sensor underwater paging system in this paper. The direct-sequence spread-spectrum techniques are investigated, and an improved all-digital non-coherent delay-locked loop for code synchronization is used. In order to get proper transmission data rate, the PN sequence employed in spread-spectrum system is a short one. If multipath interference causes adverse e ects, and the communication channel is disadvantageous for transmission, the short PN sequence can not overcome the intersymbol-interference completely. The equal-gain combination scheme and the decision-directed decision feedback equalizer, are used to enhance the performance. In addition to numerical simulations, the on-line transmission experiments in a water tank are conducted. The testing data include plain text les and simple images. The computer simulation and experimental results have shown that the all-digital underwater paging system can ful ll the expectations of the research project.
Relation: pp.168-175
URI: http://ntour.ntou.edu.tw/handle/987654321/28697
Appears in Collections:[電機工程學系] 演講及研討會

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