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频率波数分析法是一种估计信号慢度和方位角的台阵数据处理方法,在地震波信号处理中得到广泛应用,但将频率波数分析法应用于次声信号的时候,分辨率不高,易受噪声的影响,伪峰较明显。因此,本文提出了一种基于小波包分解和FK分析的次声信号参数估计方法,该方法借助小波包分解对信号整个频带的分辨能力,有效提高了算法的分辨率,降低了噪声的影响,有效压制了伪峰,并利用高斯调制正弦信号模拟次声信号,对比分析了方位角的均值、方差和均方根误差,验证了算法的性能,最后利用IS45台站接收的实际次声数据对算法进行对比分析,进一步验证了算法的有效性。 相似文献
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《声学学报:英文版》2015,(3)
次声降噪系统对提高次声监测能力具有重要作用,为分析次声降噪系统阵列结构参数变化对其降噪性能的影响规律,构建玫瑰型(rosette)管道滤波器降噪系统声电等效模型,进而利用风噪声模型和仿真数据对该模型的单进气口传递函数和系统降噪性能进行了定量分析,总结了不同阵列结构参数对该系统降噪性能的影响规律,最后对国际监测系统(International Monitoring System,IMS)玫瑰型管道滤波器的降噪性能进行了评估。仿真实验及分析结果表明:(1)进气口数量约取96,阵列尺寸约18 m,一、二级管内径取10~20 mm,一、二级合成腔体积不得超过1 L,系统能获得较好的降噪性能;(2)IMS玫瑰型管道滤波器符合最佳阵列参数设置要求;(3)满足最佳阵列参数设置的玫瑰型管道滤波器可大幅度地提高信噪比。该分析结果可为已有次声降噪系统提供性能评估,可对新的次声降噪系统设计提供参考。 相似文献
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次声降噪系统对提高次声监测能力具有重要作用,为分析次声降噪系统阵列结构参数变化对其降噪性能的影响规律,构建玫瑰型(rosette)管道滤波器降噪系统声电等效模型,进而利用风噪声模型和仿真数据对该模型的单进气口传递函数和系统降噪性能进行了定量分析,总结了不同阵列结构参数对该系统降噪性能的影响规律,最后对国际监测系统(International Monitoring System,IMS)玫瑰型管道滤波器的降噪性能进行了评估。仿真实验及分析结果表明:(1)进气口数量约取96,阵列尺寸约18 m,一、二级管内径取10~20 mm,一、二级合成腔体积不得超过1 L,系统能获得较好的降噪性能;(2)IMS玫瑰型管道滤波器符合最佳阵列参数设置要求;(3)满足最佳阵列参数设置的玫瑰型管道滤波器可大幅度地提高信噪比。该分析结果可为已有次声降噪系统提供性能评估,可对新的次声降噪系统设计提供参考。 相似文献
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全面核禁试条约第三届全球次声监测工作研讨会于1997年8月25至28日在美国新墨西哥州西班牙式的古城圣菲举行.会议云集了中国、美国、法国、俄罗斯、阿根廷、澳大利亚等5大洲12个国家61位活跃在次声学科领域的研究人员、政府官员以及联合国临时技术秘书等要员,围绕着全球次声监测中的7个专题进行报告和讨论,它们依次为:欢声阵的设计和信号处理,次声阵性能和减噪设备;法国欢声监测系统,国际次声监测系统60个站网的能力模型,对流层风对长距离次声传播的影响,高空风对次声同性能的影响,渗透管的特性以及对次声监测的减噪作用,欢声减噪器;爆炸检测,声遥感技术对爆炸源能量的估计,小当量地下,地面和近地面爆炸远距离声传 相似文献
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次声噪声场的测量与分析 总被引:1,自引:0,他引:1
本文阐述了大气次声噪声场的测量和分析方法,得到一组风速为4m/s噪声的空间相关半径,它可以作为声阵设计的初步依据;同时,还测量和计算了风噪声的速度——声压关系曲线,得到声阵在接收次声信号时的抗干扰能力。 相似文献
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次声事件的分类识别方法应用广泛,传统分类方法在很多方面进行了尝试,但由于次声信号具备非线性的特点,致使分类难度较大,分类精度不高,这对次声事件的分类工作提出了挑战。针对次声事件中的化学爆炸与天然地震信号分类问题,文章构建了一种改进的深度卷积神经网络分类模型用于实现两类次声信号的分类。论文采用"全面禁止核试验条约组织"官网上收集到的化学爆炸和天然地震次声信号进行数据集的构建,使用改进的深度卷积神经网络分别与BP网络和一维LeNet-5网络进行对比分析。实验结果表明,论文的测试识别率能够达到82.72%,较上述算法有优势。 相似文献
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Gabrielson TB 《The Journal of the Acoustical Society of America》2011,130(3):1154-1163
A worldwide network of more than 40 infrasound monitoring stations has been established as part of the effort to ensure compliance with the Comprehensive Nuclear Test Ban Treaty. Each station has four to eight individual infrasound elements in a kilometer-scale array for detection and bearing determination of acoustic events. The frequency range of interest covers a three-decade range-roughly from 0.01 to 10 Hz. A typical infrasound array element consists of a receiving transducer connected to a multiple-inlet pipe network to average spatially over the short-wavelength turbulence-associated "wind noise." Although the frequency response of the transducer itself may be known, the wind-noise reduction system modifies that response. In order to understand the system's impact on detection and identification of acoustical events, the overall frequency response must be determined. This paper describes a technique for measuring the absolute magnitude and phase of the frequency response of an infrasound element including the wind-noise-reduction piping by comparison calibration using ambient noise and a reference-microphone system. Measured coherence between the reference and the infrasound element and the consistency between the magnitude and the phase provide quality checks on the process. 相似文献
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Wenzhang Wang L. Wilson Pearson 《International Journal of Infrared and Millimeter Waves》1999,20(7):1287-1305
Results of an experimental study on finite grid oscillator arrays and the effects of the edge element loading stubs in such arrays are presented. Three finite grid oscillator arrays, based on the same unit cell, with different number of unit were fabricated on RT/Duroid 5870 substrate and tested in terms of the oscillation frequencies, radiated power and radiation patterns. It is observed that the oscillation frequency of a finite grid array differs from the theoretically prediction based on the infinite array assumption and is strongly affected by the edge element loading stubs. The measurement also indicates that mode-jumping and multi-frequency (spurious) oscillation can exist in grid oscillator arrays. 相似文献
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van Walree PA Neasham JA Schrijver MC 《The Journal of the Acoustical Society of America》2007,122(6):3495-3506
High-rate acoustic communication experiments were conducted in a dynamic estuarine environment. Two current profilers deployed in a shipping lane were interfaced with acoustic modems, which modulated and transmitted the sensor readings every 200 s over a period of four days. QPSK modulation was employed at a raw data rate of 8 kbits on a 12-kHz carrier. Two 16-element hydrophone arrays, one horizontal and one vertical, were deployed near the shore. A multichannel decision-feedback equalizer was used to demodulate the modem signals received on both arrays. Long-term statistical analysis reveals the effects of the tidal cycle, subsea unit location, attenuation by the wake of passing vessels, and high levels of ship-generated noise on the fidelity of the communication links. The use of receiver arrays enables vast improvement in the overall reliability of data delivery compared with a single-receiver system, with performance depending strongly on array orientation. The vertical array offers the best performance overall, although the horizontal array proves more robust against shipping noise. Spatial coherence estimates, variation of array aperture, and inspection of array angular responses point to adaptive beamforming and coherent combining as the chief mechanisms of array gain. 相似文献
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The Hunga-Tonga-Hunga-Ha'apai volcano in Tonga erupted violently on January 15, 2022. After 8 hours and 39 minutes, an infrasound array in Kunming at a distance of 10151 km away from the volcano recorded a sequence of strong infrasonic waves. The average period of the first four infrasonic waves is 443 s with propagation speed of 321 m/s. The azimuth angle of this event has been estimated by applying the progressive multi-channel correlation(PMCC) method to process the received signals. During continuous monitoring, the infrasonic waves propagating along and opposite to the direction towards the Kunming array around the earth are recorded respectively. 相似文献
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基于有限时域差分方法将大气中近似到二阶的非线性波动方程进行离散化,得到了数值模拟所采用的差分方程. 在此基础上,对线阵列辐射的脉冲声波在非均匀运动大气中的垂直和斜向传播进行了二维数值模拟,模拟了武汉地区(114:20°E, 30:37°N)在夏季和冬季UT=29000 s时开始传播的脉冲声波在不同时刻的声压分布. 模拟时通过采用Msise00和HWM93 两个大气模型,考虑了由于大气温度和密度变化以及大气风场存在所引起的大气不均匀性和运动性. 通过研究上述两季有风与无风条件下的声压差值pr,可以发现:风场对次声波在传播中声压分布的影响较大;由于不同季节和不同传播距离上"有效声速"的不同,导致了两季pr分布波形存在差异;风场对声波非线性传播的影响要远大于其对线性传播的影响.
关键词:
次声波传播
非均匀运动大气
有效声速 相似文献
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We analyze the problem of interference cancellation in OFDMA cellular communication systems employing adaptive antenna arrays
at the receiver and operating in the channels with frequency-selective fading and interference from the neighboring base stations.
This problem is very important for modern broadband cellular systems operating with a low coefficient of multiple use of frequencies.
Under such conditions of the network deployment, the system efficiency is restricted by the level of intrachannel interference
from the neighboring base stations transmitting in the same frequency channel. In this work, we analyze different methods
for measuring the interference characteristics and using them for spatial processing of received signals. Five different methods
for signal processing in an adaptive antenna array of the receiver are discussed. Each approach (reception method) has its
own interference immunity and complexity degree. Comparative analysis of the interference immunity of the considered receivers
has been performed for different frequency-channel loads and different numbers of interfering stations. Recommendations for
using the considered receivers are given. 相似文献
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Gibbons SJ Ringdal F Kvaerna T 《The Journal of the Acoustical Society of America》2007,122(5):EL158-EL164
A database has been established of seismic and infrasonic recordings from more than 100 well-constrained surface explosions, conducted by the Finnish military to destroy old ammunition. The recorded seismic signals are essentially identical and indicate that the variation in source location and magnitude is negligible. In contrast, the infrasonic arrivals on both seismic and infrasound sensors exhibit significant variation both with regard to the number of detected phases, phase travel times, and phase amplitudes, which would be attributable to atmospheric factors. This data set provides an excellent database for studies in sound propagation, infrasound array detection, and direction estimation. 相似文献