Analysis of focal resolution for time-reversal arrays

• Main Authors: Ming-Hung Lin, 林明宏
• Other Authors: Chi-Fang Chen
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/53300458637292013629

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 94 === Time-reversal processing is developed to enhance underwater acoustic communication in recent years. This technique has been introduced as an approach to compensate for distortion due to multiple path effect in propagation. In this thesis, the main objective is to analyze focal resolution (spatial and temporal resolution) and its relationship with element-number and the position of the time-reversal array. In the low-frequency part, simulation results of low-frequency signals received by the time-reversal array and retransmitted back to the source location are presented. In the high-frequency part, the time-reversal array is constructed with eight B&K-8104 hydrophones, and a NTU-ESOE water tank experiment is conducted to refocus signal. The experiment is also simulated using the image method to analyse the relation between the element position and the focal structure with cross-correlation function. The results of this research can help to provide the optimal design in building time-reversal array in the future.