臺灣博碩士論文加值系統

本論文主要在探討橫向超聲波濾波器繞射效應引起的頻帶響應變形的現象(相較於理想響應而言)並加以補償。論文一開始探討繞射現象的成因，建立繞射的數學模型。再檢驗已發表的數種補償法，其主要可分為時域補償與頻域補償兩大類。而後選取最有效的方法發展出程式。最後利用時域補償法設計一應用於數位廣播(DAB)的中頻濾波器。

This thesis describes the compensation of the distortion in the transversal SAW filter due to diffraction effect.The origin of the diffraction phenomenon is presented and the mathematical model of the diffraction response is established. Several compensation methods which are classified into in time domain and frequency domain are evaluated. Accordingly, a computer program with effective algorithm is developed.Its capability is demonstrated in the design of an IF bandpass filter applied in Digital Audio Broadcast(DAB).

目錄 頁次
中文摘要.…………….………………………………………………..i
英文摘要.……………….……………………………………………ii
誌謝.……………………………………………………………iii
目錄.……………………………………………………………iv
圖目錄……..…………………………………………………………………v
第一章 緒論..................................................1
1.1 前言..............................................3
1.2 平面波的繞射現象..................................4
1.3 繞射補償的方法概論................................6
1.4 簡介..............................................7
第二章 SAW IDT考慮繞射現象之頻率響應的數學推導..............7
2.1 以SAW的IDT的結構(interdigital transducers
of surface acoustic wave)來實現橫向濾波器(transversal
fliter) ...........................................7
2.2 SAW IDT filter 之轉換函數的推導......................9
2.3 在異質材料中，探討SAW IDT結構之繞射效應與波束擾動(beam steering)的關係....................................11
2.4 IDT 繞射場的公式推導...............................16
2.5 以128∘LiNbO3 材料為基質的IDT 繞射響應..............18
第三章 繞射效應之寬頻補償...................................22
3.1 寬頻補償法之頻域補償................................22
3.2 寬頻補償法之時域補償................................34
第四章 带通濾波器的設計，並顯示其繞射補償結果................45
第五章 結論.................................................56
參考文獻.....................................................57

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