With the development of underwater acoustic technology, transducer is developing towards low frequency, wide band and high power. Therefore, it puts forward higher request to underwater measurement technique. In order to improve the present measurement technique, WU Benyu, MO Xiping and CUI Zheng of Institute of Acoustics, Chinese Academy of Sciences carried out a series of studies and proposed a spatial domain processing method for low frequency transducer measurement in a reverberant tank.

With the changeless distance between the transmitter and the receiver, this method changes the different many positions of both two transducers in a limited water area irregularly and makes the contributes of the same frequency reflections randomly and irregularly. Then the reflections will be eliminated after all of the signals in different positions synchronized and superposed, and after that the direct signal what the researchers need is obtained. It overcomes the difficulty that conventional pulse comparison technique can’t obtain the direct signal because of the effect of reflections. In a reverberant tank with the size of 5 m×7m× 6 m, the measurement result of a transducer sample accords with the measurement result in a lake in the frequency range from 400 Hz to 2500 Hz.

The achievement of the measurement method makes rapid progress in the measurement ability for low frequency transducer in a reverberant tank and it makes the frequency lower limit be reduced an order of magnitude than conventional pulse comparison technique.