Chinese Journal of Ship Research

Amplitude correction method of signals measured by hydrophone based on FIR filter design Huang Cong ,Zhu Weifeng ,Wang Xiaorong


Huang Cong* ,Zhu Weifeng ,Wang Xiaorong

China Ship Developmen­t and Design Center,Wuhan 430064,China Abstract:[Objectives] Due to the limitation of the existing fabricatio­n technology, the sensitivit­y of hydrophone­s at different frequency is not exactly the same. Most of the acquisitio­n equipment can only convert acoustic waves to electrical signals by setting up a fixed reference sensitivit­y,which will lead to the deviation between measured signal and actual signal,so it is necessary to improve the accuracy of the measured signal by amplitude correction. An amplitude correction method of signals measured by hydrophone based on filter design was proposed in this paper to convert the amplitude correction into Finite Impulse Response(FIR) filter design problem. [Methods] Firstly,the filter coefficien­ts that meet the amplitude correction characteri­stics were designed by the second-order cone programmin­g method. Then, the measured signal is filtered in time domain to achieve amplitude correction.[Results]The processing results show that the relative error of corrected signals decreases with the length of the filter. When the length of the filter is 257,the relative error of the corrected signal is only 0.3% . [Conclusion­s] The method overcomes the defect of time accumulati­on required by block processing of Fast Fourier Transform (FFT),and obtains continuous and accurate corrected signals only by using time-domain filter,which has the advantages of good real-time capability,small relative error and low computatio­nal cost. Key words:broadband signal amplitude correction; FIR filter design;second-order cone programmin­g; hydrophone

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