Abstract: It is a fact for the secondary source method that the pump source impedance can’t be computed with the current estimation algorithm when the transducer length of the reference pipe is multiple times of the pressure wavelength, and the signal processing is complicated and time consuming, so the secondary source method is inapplicable in industry. For solving the problem, a new estimation algorithm of the pump source is discussed, and a signal processing software based on Matlab/GUI for secondary source method is designed. The test principle of the secondary source method is depicted, and then several evaluation methods of source impedance (such as the linear interpolation method, the weighted linear regression technique and the distributed-parameters method) and its application are discussed. With the Matlab/GUI, a signal processing software for the secondary source method is developed and then validated with test results. It can be concluded from the test results that compared with the distributed-parameter method, the computing time of the source impedance with the weighted linear regression Technique is reduced 70%. At the same test accuracy, the signal processing of the secondary source method is simplified and the computing time is reduced 80% by the software. Therefore, with the signal processing software, the application of the secondary source method in industry is possible.

Key words: secondary source method, source impedance, weighted linear regression technique