聲源法應用於全像暫態聲場之研究

Development and Application of Similar Source Method for Transient Acoustic Holography

本文內容主要針對暫態輻射聲場之預估，利用以近似聲源法（similar sound method）為基礎之平面近似聲源法，預估空間聲場中任一平面的聲壓分佈情況，並導入短時傳利葉轉換（short-time Fourier transform）的觀念，利用視窗子函數交記號分成許多小段記號，並假設每一小段記號內的變化為穩態，使得原本只能分析穩態記號的平面近似聲源法也能適用於暫態記號之志場預估，最後將利用實驗，證明此方法之可行性。 In the present study, a modified version of similar source method is developed to describe the transient sound pressure distribution in a planar surface. The method imports and idea from Short-Time Fourier Transform. It uses windows function to divide signal into a lot of sections. And it is assumed that every section of signal is stationary such that similar source method can be used to estimate transient sound field. Several test examples are shown to verify this approach.