臺灣博碩士論文加值系統

海底地震儀(Ocean Bottom Seismometer, OBS)可將地震波轉爲電子訊號記錄，取得較精確之海域所發生的地震訊息。但是能量較小的遠震會被海洋各種背景雜訊掩蓋，導致海底地震儀接收到的資料無法分離出遠震。這些環境雜訊中，亞重力波(infragravity wave)是海洋環境裡因波浪與近岸交互作用後所產生的長週期訊號，恰好與遠震低頻訊號範圍重疊。而差動式壓力計(Differential Pressure Gauge, DPG)可以偵測因水面微小高度變化而造成水中些微壓力變化的低頻率之波動，若海底地震儀結合差動式壓力計佈放在海床，便可利用差動式壓力計量出頻率範圍在0.003Hz $sim$ 0.03Hz之亞重力波，再各別分析海底地震儀與差動式壓力計收到的訊號，就可知道海底地震儀收到的遠震訊號是否有被亞重力波影響。但是差動式壓力計的頻率響應是否能涵蓋亞重力波在海洋裡所造成的週期性之壓力變化為關鍵性問題，因此本研究開發一套機構，利用簡諧運動使差動式壓力計可以在小型水槽進行週期性之壓力差測試，並將收到的數據進行頻譜分析以得知頻率響應及特性，以便掌握其性能是否足以分離亞重力波。

An Ocean Bottom Seismometer (OBS) is an instrument designed to record seismic waves as electronic signals, in order to obtain more precise seismic information from the surrounding waters. However, teleseismic waves have a low energy level, such that teleseismic signals typically cannot be distinguished from the ambient noise received by an OBS. Among the different types of ambient noise received by an OBS, infragravity waves are long-period signals, generated by the interactions between ocean waves and coastlines, which essentially overlap the low-frequency teleseismic signals. A Differential Pressure Gauge (DPG) is an instrument designed to detect low-frequency changes of pressure in the water, due to small fluctuations of the water surface. Therefore, an integrated system comprised of an OBS and a DPG is able to detect infragravity waves with frequencies ranging from 0.003 Hz to 0.03 Hz by the DPG. As a result, teleseismic waves received by the OBS can be analyzed to determine whether or not they interfered with infragravity waves. The critical issue of this research is that whether a DPG has a frequency response that can cover the periodic changes of pressure in the ocean caused by infragravity waves.Thus, in this research, we developed a mechanism that drives a DPG with simple harmonic motion inside a small water tank for periodic pressure tests. We also performed spectrum analysis on the DPG data to obtain the frequency response and characteristics of the DPG, so as to evaluate the DPG''s capability of detecting infragravity waves in the ocean.

論文審定書. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
致謝. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
摘要. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
圖目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
表目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
第一章緒論. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 前言. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 文獻回顧. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 研究目的. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.4 論文架構. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
第二章壓力差測試機構開發. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1 簡諧運動機構設計. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 馬達選用與驅動方式. . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 傳動機構設計. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4 機構組裝. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
第三章壓力計本體測試. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.1 測試規劃. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.2 頻譜分析. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.3 測試結果. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
第四章微型放大濾波電路板測試. . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1 測試規劃. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.2 公分級振幅測試. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.3 公厘級振幅測試. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.4 測試結果. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
第五章討論與結論. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.1 討論. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.2 結論. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
參考文獻. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
附錄A 接NF 放大濾波器之頻譜分析. . . . . . . . . . . . . . . . . . . . . . . . . 49
附錄B 接微型放大濾波電路板之頻譜分析. . . . . . . . . . . . . . . . . . . . . . 56

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