Aiming at the shortage of conventional threshold function in wavelet noise reduction of chaotic signals,we propose a wavelet-packet noise reduction method of chaotic signals based on a new higher order threshold funct...Aiming at the shortage of conventional threshold function in wavelet noise reduction of chaotic signals,we propose a wavelet-packet noise reduction method of chaotic signals based on a new higher order threshold function.The method retains the useful high-frequency information,and the threshold function is continuous and derivable,therefore it is more consistent with the characteristics of the continuous signal.Contrast simulation experiment shows that the effect of noise reduction and the precision of noise reduction of chaotic signals both are improved.展开更多
针对近场信源定位中自由度小、准确性低等问题,提出一种基于四阶累量矩阵的定位算法。首先构造等效导向矢量包含波达方向(Direction of arrival,DOA)和距离信息的高维虚拟协方差矩阵,在角度估计中,提出基于矩阵秩亏来搜索最小奇异值倒...针对近场信源定位中自由度小、准确性低等问题,提出一种基于四阶累量矩阵的定位算法。首先构造等效导向矢量包含波达方向(Direction of arrival,DOA)和距离信息的高维虚拟协方差矩阵,在角度估计中,提出基于矩阵秩亏来搜索最小奇异值倒数的一维搜索方法,降低了计算量,在增大自由度的同时利用高斯噪声高阶累量为零的特性提高了低信噪比下的性能;在不进行额外计算的前提下,直接利用角度估计中进行奇异值分解时得到的奇异向量所包含的距离信息,通过最小二乘法得到距离。仿真结果表明,相比于已有算法,该方法可以仅在一个高阶累量矩阵中通过一维搜索估计角度和距离,在降低复杂度的同时提高了准确性,并且提出方法的自由度是降维多重信号分类方法的2倍。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 10731050the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China under Grant No IRTO0742。
文摘Aiming at the shortage of conventional threshold function in wavelet noise reduction of chaotic signals,we propose a wavelet-packet noise reduction method of chaotic signals based on a new higher order threshold function.The method retains the useful high-frequency information,and the threshold function is continuous and derivable,therefore it is more consistent with the characteristics of the continuous signal.Contrast simulation experiment shows that the effect of noise reduction and the precision of noise reduction of chaotic signals both are improved.
文摘针对近场信源定位中自由度小、准确性低等问题,提出一种基于四阶累量矩阵的定位算法。首先构造等效导向矢量包含波达方向(Direction of arrival,DOA)和距离信息的高维虚拟协方差矩阵,在角度估计中,提出基于矩阵秩亏来搜索最小奇异值倒数的一维搜索方法,降低了计算量,在增大自由度的同时利用高斯噪声高阶累量为零的特性提高了低信噪比下的性能;在不进行额外计算的前提下,直接利用角度估计中进行奇异值分解时得到的奇异向量所包含的距离信息,通过最小二乘法得到距离。仿真结果表明,相比于已有算法,该方法可以仅在一个高阶累量矩阵中通过一维搜索估计角度和距离,在降低复杂度的同时提高了准确性,并且提出方法的自由度是降维多重信号分类方法的2倍。