复倒谱域水声信道多途抑制技术

Anti-multipath technique of underwater acoustic channel in complex cepstrum domain

水下声信道因边界反射及介质不均匀性而呈现多途特性,如何采取有效措施抑制信道多途影响一直以来都是水声领域的难点和热点问题。基于同态滤波基本原理,研究了水声多途信道的复倒谱特性,据此提出了一种适用于将信道与信号分离的复倒谱域特征滤波器构建方法,并与常用的低通特征滤波器、梳状特征滤波器进行了对比分析。研究结果表明,提出的方法可有效抑制信道多途,且与上述2种特征滤波器比较,所提方法具有构建方法简易、重构信号误差较小等特点,具有工程应用价值。

Because of boundary reflections and the non-homogeneity of water in the sea,an underwater acoustic channel is regarded as a multipath channel. Therefore managing multipath interference effectively has always been a difficult and hot issue in underwater acoustics. Based on the fundamental theory of homomorphic filters,the characteristics of an underwater multipath acoustic channel in a complex cepstrum domain were analyzed. Then a new kind of feature filter,pinnacle search method,which is suitable for separation of the signal and the channel in a complex cepstrum domain,was put forward. The features of this method were analyzed and compared with the low-pass feature filter and the comb feature filter. The results show that the proposed method can manage the multipath effects effectively. Compared with the other two feature filters,the pinnacle search feature filter can easily be established with smaller error in reconstructing signals,and so is valuable in engineering application.