Based on the system of B&K3560C data acquisition and analysis. The sound insulation of underwater acoustical material is measured in large anechoic tank, the concepts of the transmitted pulse width and analyzed pulse width are presented. Different transmitted pulse width and analyzed pulse width are adopted for different measurement frequencies and the method of advanced acquisition and analysis is also used in signal analysis and disposal. The results show that the improvement is feasible, which can improve the measurement precision of pulse method in low frequencies and break the measurement frequency limitation of traditional approach. The lowest effective measurement frequency can reach to 500Hz.

underwater acoustical material; pulse method of sound insulation measurement; advanced acquisition and analysis; transmitted pulse width; analyzed pulse width