【作者】 刘燕青；

【导师】 李志舜；

【作者基本信息】 西北工业大学 ， 信号与信息处理， 2003， 硕士

【摘要】 盲信号处理技术是最近一段时间兴起的一个新的研究领域，它在实际中有着非常广泛的应用，盲信号源分离是盲信号处理技术的一个研究方向。盲分离是指在不知道源信号的特征，而且也不知道信号在传输通道中的混合过程，只假设源信号是相互统计独立的情况下，从观测信号中分离出源信号的技术。本文研究瞬时混合情况和卷积混合情况下的自适应盲分离算法。 盲分离算法需要用到高阶统计量，互累积量迫零法是一种直接利用高阶统计量的自适应盲分离算法。本文介绍了高阶累积量，通过互累积量的性质阐述了算法的基本思想，分析了算法的稳定性能，对算法进行了仿真，指出了算法的不足。 Infomax算法是另外一种自适应盲分离算法。Infomax算法通过引入非线性函数来引入高阶统计量，并利用信息论的基本知识推导出了盲分离算法。Infomax算法适用于瞬时混合情况下的盲分离和单通道盲解卷积问题，本文将Infomax算法推广到多通道卷积混合，对算法进行仿真，取得了不错的效果。 自然梯度下降法是一种新的最优化方法，自然梯度下降法是在黎曼空间下提出的，自然梯度相比于标准梯度有很多优点。自适应盲分离算法中的系数空间是黎曼空间，本文将自然梯度下降法应用于Infomax算法可以改进算法的性能，有利于算法的数值稳定性和提高算法的收敛速度。针对基于自然梯度算法的特殊结构，还详细分析了算法的性能，包括稳定条件，步长因子和非线性函数对算法的影响。 将盲分离算法应用于实际是最根本的目的。本文通过用盲分离算法对水池实验数据进行处理，初步探索了盲分离在水声环境下的应用，并得到了在水声环境下应用盲分离算法的一些结论，指出了以后需要改进的地方。更多还原

【Abstract】 Blind signal processing is a new orientation in the field of signal processing, it also has broad range of application in daily life. Blind source separation is to separate sources from mixed signals, without knowing about the characters of the sources and how they are mixed, only assuming that the sources are independent with each other. Blind source separation is a part of blind signal processing. This paper only does research on adaptive blind source separation algorithm in two mixture models梚nstantaneous mixture and convolutive mixture.Blind source separation needs high order statistics. The algorithm based on cross cumulants uses high order statistics directly. The basic idea of the algorithm is shown by the characteristics of cumulants; the performance of the algorithm is discussed; the shortcomings of it are pointed out.Infomax algorithm is another adaptive blind source separation. Infomax uses high order statistics by non-linear function and the idea from Information Theory. The original Infomax is only applied in the instantaneous mixture and in the single channel blind deconvolution. This thesis applies the idea to blind sources separation in multiple channel convolutive mixture. Through simulation, we can show that the algorithm has good performance.Natural gradient is a new optimization way that is proposed in a special space?Riemannian Space. The parameter space in blind source separation is Riemannian Space. Natural gradient has many better characters compared with normal gradient. This thesis applies natural gradient to Infomax algorithm. And with the special character of the natural gradient, the performance of the algorithm is discussed.Applying blind source separation to the real situation is the basic goal. This paper uses the blind source separation algorithms to process the data received form an experiment in water tank.更多还原