Study On Digital Compensation Techniques For Linear Distortion Of Wideband Underwater Acoustic Transmitter

Sonar is an effective equipment of underwater detection,communication and positioning.As the main acoustic part of sonar,the performance of underwater acoustic transmitter is directly related to the performance of sonar.With the continuous increase of sonar bandwidth,the transmitter usually has the linear distortion,which greatly reduces the performance of sonar.In order to ensure the quality of wideband acoustic signals,the linear distortion of the transmitter must be minimized.In this paper,a digital compensation filter is designed to solve the linear distortion of wideband underwater acoustic transmitter.The main research content of this paper is the design of digital compensation filter for linear distortion of wideband underwater acoustic transmitter.This paper includes the identification of the non-parametric model of the underwater acoustic transmitter,the design of digital compensation filter and the verified experiment in the pool.Aiming at two non-parametric models of underwater acoustic transmitter,two different compensation methods are adopted: frequency domain compensation method and time domain compensation method.Firstly,the frequency response model and impulse response model of two non-parametric models of underwater acoustic transmitter are identified by spectral analysis method and correlation analysis method respectively,and the identification performance is simulated and analyzed.Secondly,the frequency domain compensation method is based on the frequency domain response model,and the second order cone programming and active set method of convex quadratic programming are used to design the digital compensation filter and the two design methods are simulated and analyzed.Time domain compensation method is based on impulse response model,and Levinson recursive algorithm is used to design digital compensation filter.Finally,the validity and feasibility of the frequency domain compensation method are verified by a pool experiment and the compensation effect of the linear distortion in the direction of the main axis of the transducer basically reaches the expected goal.