肺部是成對的組織，但在結構上並不是完全的對稱。右肺有三葉、左肺有兩葉，且支氣管在左右肺部的分布也不同。根據肺部和支氣管結構的不同，我們假設左右肺音訊號會有差異性。
本實驗研究共42位，年齡介於18-22歲自願者，無吸煙習慣且經過醫院檢查無任何肺部疾病。每位受測者量測七對位置(前胸三對，側胸一對與後胸三對)。使用電容式麥克風與放大濾波電路擷取肺音訊號；另外使用熱敏電阻偵測吸氣與吐氣的狀態，這些訊號透過MP3 Player儲存。
軟體設計利用Matlab撰寫程式，將訊號做快速傅立葉轉換(FFT)，比較左右肺部在頻譜上的差異性。在分析前胸三對量測點之F50有顯著差異性(p<0.05)，右肺對應的頻率會比左肺高。比較左右肺的總功率，發現在前中胸、前下胸左肺的總功率會大於右肺。根據以上的結果，發現肺音訊號會因結構上的差異產生不一樣的特性。在未來可以繼續分析有疾病的病患，進而輔助醫生診斷疾病。

The lung is a tissue in pairs but it is not completely symmetric on structure. The right lung has three lobes and the left lung has two. Distribution of bronchus is different on left-right lungs. According to the difference of organ on left-right lungs, we assume that the sounds of left-right lungs are different.
Forty two volunteers from 18 to 22 years old without smoking habits and any lung diseases participated in this experiment. We record lung sounds from seven pairs of detecting points (three pairs of points in the anterior, one pairs of points in the lateral, three pairs of points in the posterior).We use electric condenser microphone, amplifier, and filter circuit to record lung sound. Besides we also detect the states of inspiration and expiration by thermistor. Signals are stored up by MP3 Player.
Using FFT analyzes the lung sounds by using Matlab and compares the difference of spectrums. The results show that F50 have significant differences (p<0.05) in the anterior. The frequency of right lung is higher than frequency of left lung. Compared total power, the value of left lung is bigger than the value of right lung on the middle anterior and lower anterior. The different structure of lung can make the different sounds between the left lung and the right lung. In the future, we can help doctor to diagnose the disease of lung.

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