Two-Hydrophone Technique Based Reflection Coefficient Estimation and Interference Reduction Approaches in a Sound Tube
Yingying Zhang · Shandong kexue · 2009
We investigate interference formation and its transmission paths in a sound tube with a mathematical model to estimate the interference grade in a thin air-layer and sound reflection coefficient.We discover that reflection coefficient estimation is dependent on the tube wall vibration caused by the mechanical connection between sound source and tube wall.We therefore propose two approaches to reduce the interference.One is the rational tube structure design to keep the mechanical connection between tube bottom side and cylindrical transducer gasket loose.The other one is the wall radial rate measurement in the position of a standard hydrophone to estimate reflection coefficient.Experiments and calculations show that a small plastic spring is effective for interference reduction.