The Analysis and Correction of Time-Delay in the Precise Acoustic Measurement System

The acoustic transducer is a nonlinear system, which will cause a time delay to signals. The system group and phase delay have a large influence on the results in the transmit-time measurement. In order to solve the problem, this paper proposes to use the signal phase difference to eliminate the phase delay, and precisely determine the group delay by the method of experiment. At first, this paper theoretically proves that the group delay of the acoustic measurement system is constant, and the phase delay changes over signal frequency, then it analyzes the influence of group and phase delay on the measuring results and meanwhile puts forward a method to use the multi-frequency signal phase difference to eliminate group delay .Finally, it achieves the group delay through experiments, and there is a good consistency between the experimental results and theoretical analysis.