微型喇叭運用於行動電話之分析與設計

Abstract

近年來遠端通訊工業的快速發展。手機與個人數位助理等通訊產品對於聲音品質的要求是重要的。運用在這些產品的揚聲器稱為微型喇叭。微型喇叭是由振膜、音圈與框架組合而成，而這些物體的大小、形狀與材料性質會對微型喇叭的聲學特性造成影響。 在這篇的論文中，我們將經由實驗與模擬的結果來分析微型喇叭。並且使用機電聲類比電路去模擬微型喇叭裝置於行動電話的動態響應。而機電聲類比電路則是利用電路分析的概念。對於機電聲類比電路參數的計算，在這裡我們採用測試箱法與曲線逼近的方式來求得。 在電聲學裡，管路通常被當作只有質量效應，而管路的自然共振效應卻被忽略。在這篇的論文裡，我們將運用不同的方法去模擬管路的共振效應。 開孔式與被動輻射式的揚聲器音箱設計概念被運用於行動電話的音箱設計，以增強低音的效果。

The telecommunication industry is growing rapidly. The demand of sound quality is important in these telecommunication products like mobile phone or PDA. Loudspeakers applied in these products are called miniature speaker. Miniature speakers consist of a diaphragm, voice-coil and frame whose shape, size and material properties dominate the acoustic characteristics of them. In the paper, miniature speakers are analyzed by the experiment and simulation results. Electro-mechano-acoustic (EMA) analogous circuit is used to simulate the dynamic response of miniature speakers placed in mobile phone. Delta compliance and curve fitting method is adopted to calculate the parameters of the EMA analogous circuits. In theory of electroacoustics, duct is modeled by acoustic mass, but the natural resonance frequency of duct is never considered. In this paper, the lumped parameter oscillator model is used to model the natural resonance frequency of duct. And another method to model the resonance of duct is mentioned. The method of vented-box and passive radiator design is applied to design the well enclosure for mobile phone and enhance the bass response.