聽診器(stethoscope)是醫生在進行臨床診斷時最重要的工具之一，其優點為以非侵入的方式，利用聽取人體內心、肺、胃腸等臟器發出的聲響，進行相關疾病的診斷。聽診器自1816年由法國醫生R. Laennec發明以來，經過了將近兩個世紀的演進，從過去早期的鐘式(bell)聽診器到現今結合麥克風感測元件的電子式聽診器。由於現代電腦科技的發達，近年來電子式聽診器正逐漸發展為電腦化的醫療輔具，透過電腦數位訊號處理的方式，可協助醫生更精確地進行診斷。
以訊號處理系統而言，聽診器內傳遞聲波的部件本身的頻率響應特性會影響聲波訊號的變化，而且在臨床量測時，容易受到磨擦音和環境噪音的干擾。醫生在進行聽診時可辨別這些干擾音與人體生理音的差異；但若欲進行電腦化聽診，訊號處理程式則難以分辨干擾音與生理音。為了解決此訊號處理上的問題，本研究利用有限元素分析法(Finite element analysis, FEA)來模擬聽診器的聲波特性，希望能藉此以科學的方式來取得更好的聽診器外形和材料之設計參數。
為了驗證有限元素分析結果的正確性，本研究以聲學系統之集總參數模型(lumped-parameter model)為基礎，探討聲波元件的頻率響應變化，並以自製的電腦量測介面，以實物量測的方式測量聽診器實物的頻率響應，證實模擬的結果符合預期。

The stethoscope is one of the most important tools in clinical diagnosis, owing to its ability in facilitating non-invasive diagnosis from auscultation of internal organs. After nearly two centuries of evolution since being invented by French physician R. Laennec in the year 1816, the stethoscope has changed from the early bell stethoscope to the present electronic stethoscope. Recent technology development further promotes computerized diagnosis from digitalized auscultation signals by way of digital signal processing algorithms. All these progresses lead to a handier tool and more accurate diagnosis by the physicians.
In terms of signal processing systems, electronic stethoscopes can be regarded as a sensing component of acoustic waves. Its acoustic frequency response will affect the measured signals. Moreover, friction and environmental sounds are easily picked up by the stethoscope. These cause the physicians not much difficulty because human can easily distinguish between these interferences and the physiological signal. However, computer programs have not been able to distinguish. To solve this problem, this research uses finite element analysis (FEA) to simulate the acoustic characteristics of stethoscopes, hoping to achieve better stethoscope design parameters in shape and material.
After FEA simulation, lumped-parameter model of the acoustic system is used to explore changes in the frequency response of the acoustic component. In addition, physical measurements are performed with acoustic interface hardware. The FEA simulation is thus verified.

M. D. Blaufox, An Ear to the Chest: An Illustrated History of the Evolution of the Stethoscope, The Parthenon Publishing Group Inc, 2001.
聶族剛, 肺音聽診系統之可行性研究, 國立中央大學電機工程學系碩士論文, 2005.
紀國瑞, 數位聽診器之原型, 國立中央大學電機工程學系碩士論文, 2005.
溫祖建, 電腦化肺音擷取系統, 國立中央大學電機工程學系碩士論文, 2005.
余宗霖, 氣喘肺音監測系統之可行性研究, 國立中央大學電機工程學系碩士論文, 2005.
陳精一, ANSYS電腦輔助工程實務分析, 全華圖書, 2010.
S. Moaveni, 有限元素分析 : 理論與應用ANSYS, 陳新郁,林政仁 譯, 高立圖書有限公司, 2007.
R. Z. Gan, B. Feng and Q. Sun, "Three-dimensional fnite element modeling of human ear for sound transmission," Annals of Biomedical Engineering, vol. 32, no. 6, pp. 847-859, Jun. 2004.
R. Z. Gan, Q. Sun, B. Feng and M. W. Wood, "Acoustic–structural coupled finite element analysis for sound transmission in human ear—Pressure distributions," Medical Engineering & Physics, vol. 28, no. 5, pp. 395-404, Jun. 2006.
R. Z. Gan, B. P. Reeves, and X. Wang, "Modeling of Sound Transmission from Ear Canal to Cochlea," Annals of Biomedical Engineering, vol. 35, no. 12, pp. 2180-2195, Dec. 2007.
J. C. Zuercher, E. V. Carlson and M. C. Killion, "Small acoustic tubes: New approximations including isothermal and viscous effects," The Journal of the Acoustical Society of America, vol. 83, no. 4, p. 1653–1666, Apr. 1988.
P. Harper, S. S. Kraman, H. Pasterkamp and G. R. Wodicka, "An acoustic model of the respiratory track," IEEE Transactions on Biomedical Engineering, vol. 48, no. 5, p. 543–550, May. 2001.
P. Y. Ertel, M. Lawrence, R. K. Brown and A. M. Stern, "Stethoscope Acoustics II. Transmission and Filtration Patterns," Circulation, vol. 34, no. 5, pp. 899-909, Nov. 1966.
M. Abella, J. Formolo and D. G. Penney, "Comparison of the acoustic properties of six popular stethoscopes," The Journal of the Acoustical Society of America, vol. 91, no. 4, pp. 2224-2228, Apr. 1992.
劉金源, 水中聲學-水聲系統之基本操作原理, 國立編譯館, 1991.
白明憲, 工程聲學, 全華圖書, 2008.
Anonymous, "Theory Reference. Chapter 8: Acoustics," in ANSYS Documentation, ANSYS, Inc..
A. Craggs, "A finite element model for acoustically lined small rooms," Journal of Sound and Vibration, vol. 108, no. 2, p. 327–337, 22 Jul. 1986.
Anonymous, "Fluids Guide II. Acoustics 1. Acoustics," in ANSYS Documentation, ANSYS, Inc..
D. K. Cheng, Field and Wave Electromagnetics, 2nd ed., Addison-Wesley, 1989.
A. V. Oppenheim, A. S. Willsky and S. H. Nawab, Signal & system, 2nd ed., Prentice-Hall International, 1997.
B. C. Baker, "資料擷取系統最佳濾波器的選擇與設計原理Part II," http://www.eettaiwan.com/. [Online]. [Accessed 9 2013].