Applied method of broadband technique in underwater acoustic measurement

A method based upon broadband analysis technique to make the underwater acoustic measurement is named broadband noise comparison method.From the viewpoint of frequency domain analysis,according to the actual demand and by modifying Welch method,it uses the noise signal source and applies modern signal processing technique and digitalizer hardware system to achieve a rapid and efficient broadband measurement with a hydrophone in the broadband noise comparison calibration system.This is an important supplement to single-frequency pulse comparison method.For the measurement of high Q-factor underwater transducers,the broadband noise comparison method has a good advantage in preventing transient effect.Also by comparing with the measuring results in different sampling rate,a conclusion can be drawn that the broadband noise comparison method adopts the way to average the sum of pulse sequence processing results,and reduces the requirement of sampling rate.That is to say,the higher frequency measurement can be achieved under the certain condition of the fixed maximum sampling rate of the instrument.