海洋自然噪声场空间互功率谱

本文以海洋自然噪声场局部谱理论为基础,给出了海洋自然噪声场空间互功率谱的一般表示式,计算了几种典型情况下的空间互功率谱。对声速均匀分布的深海模型,得到的结果比Cron和Sherman(1962年)多了一个附加项,即不均匀平面波对噪声场的贡献。当接收器深度远大于接收器之间的间距时,此附加项可以忽略不计。最后,将某些理论计算的结果同早先获得的实验资料作了比较。     

浅海低噪声信道模型

本文根据海洋噪声场随机局部谱展开理论,分析了典型浅海负梯度(或负跃层)下低噪声信道的理论模型。结果表明,对于几百赫以上的表面风关噪声,在上述水文分布和广泛的海底类型下,噪声场具有鲜明的低噪声信道特征。     

SPATIAL CROSS-SPECTRA OF AMBIENT SEA NOISE FIELD

The general expression of the spatia lcross-spectral density function of ambient sea noise field isdeveloped,based on the theory of"local spectrum of underwater ambient noise field"presented byXu Zhenyong(1977).Spatial cross-spectra of several typical cases are calculated.The resultantexpression for deep-sea model with the uniform sound velocity profile is consistent with that developedby Cron and Sherman(1962,1965)except for an additional term which is due to inhomo-geneousplane waves and can be neglected when the depth of receivers is much greater than the distanse se-parating the receovers.Finally,the comparison of some theoretical calculations and eariler obtainedexperimental data is also given.     

引信动作(水下爆炸声源)距离测定仪

本文介绍了一种高精度微机化水下爆炸声源被动测距设备。本设备用于试验场监测运动声源或其它爆炸声源离目标靶的径向距离,以及击水和引爆的时差等数据。本设备基于水下被动测距原理,采用长直线水听器基阵、单板微型计算机及专用软、硬件,实现整个测量过程的全自动化。