宽带运动介质反向散射声信号的谱矩估计  

Spectral moment estimates of broadband backscattering acoustic wave in moving medium

作　　者：朱维庆[1] 王长红[1] 潘锋[1] 张向军[1] 

机构地区：[1]中国科学院声学研究所

出　　处：《声学学报》1996年第4期731-738,共8页Acta Acustica

摘　　要：本文假设宽带运动介质反向散射信号和噪声是彩色高斯信号，在大样本的假设下，用协方差法求得了信号谱矩一阶矩和二阶矩的均值和方差，推广了文献［８］的工作。发射信号是伪随机编码信号，它由两个相同的子序列组成，为了简化问题，又设信号和噪声的带宽和中心频率相同，得到了易用的公式。公式表明，一阶谱矩估计的均值是无偏估计，估计的方差与子序列间的相关系数ρ，信噪比Ｓ／Ｎ和ΔｆＴＬ有关，其中Δｆ、Ｔ和Ｌ分别对应子序列中码元的带宽、长度和总个数。分析了约３０００组窄带信号的海上实验数据，给出了ρ的变化范围。这些工作对研制宽带多普勒流速剖面仪（ＢＢＡＤＣＰ）是很有用的。In this paper, we suppose that the signal and noise of broadband moving medium reverberation are colored Gaussian signals. When the sample number is large, both the mean and variance of the first power spectrum moment by covariance techniques are obtained. The results obtained by D.S.ZRNIC [8] are generalized, where he assumed the noise is white. The transmitted signal is pseudo noise (PN) train and consists of two same subtrains between which the difference is only a time delay. In order to simplify the analysis, we also assume that the center frequency and frequency bandwidth of both signal and noise are equal. It is found that the mean of the first power spectral moment estimate is an unbiased estimate and that the variance of this estimate is dependent on the correlation coefficient p between two subtrains, the signal-to-noise ratio S/ N and △fTL, where △f, T and L are the frequency bandwidth, time duration and total number of pulse elements in a subtrain respectively. Three thousand groups of narrow-band-signal data obtained in field are analyzed, then we know the range of p. All these results are very useful in designing a BBADCP.

关 键 词：散射声信号 宽带 谱矩估计 

分 类 号：O422.5[理学—声学]