水听器复数灵敏度相位测时校准法

本文提出并论述了水听器复数灵敏度相位测时校准法.常规的水听器复数灵敏度校准,要求准确测定工作换能器之间的距离,但在具体实施中很难保证测量的准确度.水听器复数灵敏度相位测时校准法,就是利用时间测量取代距离测量进行灵敏度相位校准,文中阐述了水听器复数灵敏度相位测时校准法的测量原理、方法和实施步骤.     

矢量水听器低频绝对校准装置研究

提出了矢量水听器低频绝对校准装置。首先给出了矢量水听器绝对校准的原理,通过测量声源辐射面的加速度,利用驻波管中平面驻波声场中的声压、质点振速和质点加速度在垂直方向上的分布规律,得出了校准计算公式;之后对校准装置中平面驻波场在垂直方向上的分布规律进行了测量验证,并对测量用加速度计进行了校准;最后对待校矢量水听器的灵敏度和指向性进行了测试。结果表明:在10~315 Hz频带内,矢量水听器低频绝对校准装置在±1 d B误差允许范围内,可用于矢量水听器的绝对校准。     

水听器复数灵敏度校准方法探讨

本文介绍了一种水听器复数灵敏度校准的方法和步骤,并用数字采样装置实现相位的精确测量。     

矢量水听器自动校准系统的研究及实现

研制的矢量水听器自动校准系统在水声计量领域具有重要的应用价值,能够实现低频范围内矢量水听器的自动校准。利用动态信号采集卡采集被测信号和标准水听器的输出信号,对驻波管内的声场分布进行了测量分析,对系统的测量不确定度进行了分析评定,对声压灵敏度进行了比对测试。该系统校准矢量水听器的扩展不确定度为1.6dB。     

激光测振技术检测质点振速的研究

介绍了一种利用激光法直接检测2～20 kHz水介质质点振速的方法,并通过利用水介质质点振速和水听器输出电压量计算水听器自由场灵敏度的方法来验证水介质质点振速测量的准确性.     

基于激光测振法的高强度超声声场测量

基于激光测振法对高强度聚焦超声换能器的辐射声场进行测量,与标准水听器测得的结果对比焦点处基波信号、二次谐波、三次谐波测得值基本一致,基波声压误差在10%以内,焦平面的声压分布基本一致。同时,基于多层介质阻抗传递法解决激光测振法中薄膜对声场测量的影响,计算不同频率下薄膜的声压透射系数。设计实验验证不同频率(1、5、10 MHz)下,激光测振法与标准水听器测量法得到的结果,结果表明通过声压透射系数对激光测振法测量结果进行修正可有效减小测量误差。     

变温变压环境中大面积水听器灵敏度低频校准方法

针对在变温变压环境中缺少低频大面积水听器灵敏度校准手段的问题,提出了在行波管中校准水听器的半行波管法:将待校准水听器放置于行波管中,通过控制行波管两边的有源终端,在待校准水听器与辅助换能器之间形成行波场,与主发射换能器之间形成驻波场。推导了水听器灵敏度的校准公式。在常温常压环境下,通过与传统低频校准方法的比对,校准结果具有良好的一致性,证明该方法可以有效校准大面积水听器的灵敏度;在不同温度与压力环境下对水听器灵敏度的校准结果,说明了该方法在变温变压条件下校准水听器的可行性,为大面积水听器灵敏度的校准提供了一种方法;对该方法进行了测量不确定度评定,其扩展测量不确定度为3dB。     

复数阻抗法修正电缆引起的水听器灵敏度变化

压电式水听器的灵敏度会因为外接电缆的电容效应而降低,在校准和使用中需要根据延长电缆的特性对灵敏度进行修正。从水听器与外接电缆的等效电路出发,推导了复数阻抗法修正水听器灵敏度的方法。以RHS-30和RHS-10水听器为例,由水听器的复数阻抗、延长电缆的开路和短路复数阻抗计算得到了电缆引入的灵敏度修正值,并与实际测得的加电缆前后水听器灵敏度变化值做了比较,结果证明利用复数阻抗法能准确地修正因延长电缆引起的水听器灵敏度变化,与传统的纯电容修正相比,该方法具有更好的适用性。     

矢量水听器的低频相位校准方法

描述了一种在平面驻波声场中,对矢量水听器进行相位校准的方法,该方法可以在20Hz～2kHz频率范围内,对矢量水听器的矢量通道和声压通道之间的相位差进行校准.     

矢量水听器校准装置的不确定度评定

本文介绍了矢量水听器校准装置的工作原理,系统组成及校准矢量水听器灵敏度和指向性的工作流程,并对该装置的不确定度进行分析评定。     

PTB所建激光干涉振动一次绝对校准标准简析

按照ISO/16063-11：1999《激光干涉绝对法振动校准》所述,激光干涉振动一次绝对校准方法主要有条纹计数法、最小点法与正弦逼近法三种,其复现频率范围为1Hz～10kHz.而德国联邦物理技术研究院（PTB）现已建立和保存的低频、中频、高频振动激光干涉一次绝对校准标准的复现频率范围则达0.1Hz～20kHz.此外,PTB还实现了旋转运动物理量值--角加速度的复现;其复现频率范围也达到0.3Hz～1kHz.作为曾在PTB1.22实验室进行过研究工作的访问学者,作者旨在通过对PTB所建激光干涉振动一次绝对校准标准的     

一种变温环境下水听器灵敏度校准系统的设计

针对缺少在变温条件下校准水听器灵敏度方法的问题,设计了一套基于动圈换能器声管的变温水听器灵敏度校准系统。建立模型分析声管内的声压分布,并计算了变温后对灵敏度校准结果的补偿量;利用Comsol仿真不同声管厚度对声场的影响,分析了底面非均匀振动和不同尺寸的水听器对校准结果的影响,确定了合适的声管尺寸和测量方法。分别在常温与变温条件下对不同尺寸的水听器进行校准并将校准结果与标准值比较。结果表明,此系统在常温下的校准结果与标准值的偏差低于0.5 dB,变温条件下的测量结果与标准值偏差低于0.6 dB,整体系统的扩展不确定度约为1.0 dB。     

Extending the frequency range of the National Physical Laboratory primary standard laser interferometer for hydrophone calibrations to 80 MHz

A method for the primary calibration of hydrophones in the frequency range up to 60 MHz is described. The current National Physical Laboratory (NPL) primary standard method of calibrating ultrasonic hydrophones from 500 kHz to 20 MHz is based on optical interferometry. The acoustic field produced by a transducer is detected by an acoustically transparent but optically reflecting pellicle. Optical interferometric measurements of pellicle displacement at discrete frequencies in tone-burst fields are converted to acoustic pressure, and the hydrophone for calibration is substituted at the same point, allowing sensitivity in volts per pascal to be obtained directly. For calibrations up to 60 MHz, the interferometer is capable of measuring the displacement of the pellicle as a function of frequency in a harmonically rich nonlinear field up to and including the 12th harmonic of the shocked field generated by a 5 MHz focusing transducer, allowing hydrophones to be calibrated by substitution in the same field. Sources of uncertainty in the new method have been investigated. Best combined random and systematic uncertainties at the 95% confidence level for the new method are 7% at 20 MHz, 11% at 40 MHz, and 16% at 60 MHz.     

250Hz～8kHz频率范围水听器自由场校准补充比对

介绍了以杭州应用声学研究所作为主导实验室与俄罗斯国立物理技术和无线电工程测量研究院开展COOMET.AUV.W-S1:250 Hz~8 kHz频率范围水听器自由场校准国际补充比对的结果。比对校准了两只标准水听器TC 4033和GI 55。互易法和比较法及其校准装置被用于评估中俄两国在水听器自由场低频校准方面的当前水平。结果显示,中俄两国得到的两只标准水听器的自由场灵敏度校准结果具有很好的一致性,绝大多数频率点的校准结果与参考值的差值小于0.40 dB,最大偏差为0.59 dB。结果证明,中俄两国的自由场水听器校准低限可扩展至250 Hz。     

Primary calibration of hydrophones with extended frequency range 1 to 70 MHz using optical interferometry

A technique for the primary calibration of hydrophones based on an optical principle is presented. An interferometer determines the displacement of a pellicle mounted on the surface of the tank fluid perpendicular to the sound propagation axis; the known acoustic field is then measured using the hydrophone. The application range extends from 1 to 50 MHz and, with a lesser accuracy, to 70 MHz. The loaded and the open-circuit sensitivity are obtained pointwise, and the frequency and the number of the measurement points can be arbitrarily chosen. As an example, two membrane hydrophones with a spot diameter of 0.5 mm are calibrated, and the comparison with a theoretical model describing the acoustic and electrical properties of the hydrophone shows good agreement.     

Characteristics of piezoceramic and 3–3 piezocomposite hydrophones evaluated by finite element modelling

The transducer characteristics of hydrophones manufactured from porous 3–3 piezocomposites are compared with dense piezoceramic disc hydrophones using finite element modelling. Due to the complex porous structure of the 3–3 piezocomposites, a real-size 3-dimensional model was developed while a 2-dimensional axisymmetric model was constructed for the simple dense disc hydrophone. The electrical impedance and receiving sensitivity of the hydrophones in water were evaluated in the frequency range 10–100 kHz. The model results were compared with the experimental results. The sharp resonance peaks observed for the dense piezoceramic hydrophone were broadened to a large extent for porous piezocomposite hydrophones due to weaker coupling of the structure. The receiving sensitivity of piezocomposite hydrophones is found to be constant over the frequency range studied. The flat frequency response suggests that the 3–3 piezocomposites are useful for wide-band hydrophone applications.     

0.1 Hz～50 kHz直线振动幅值和相位国家计量基准系统的研究

描述中国计量科学院在直线振动幅值和相位测量的理论研究和技术实现方面取得的最新进展。简要介绍了国家高、中、低频振动基(副基)准幅相特性测量装置的系统构建、测量原理和技术实现,以及装置达到的主要技术指标。提出振动基(副基)准优化提升中关键的技术创新点,如自主提出了改进的外差正弦逼近法和基于波峰波谷的外差时间间隔法,在压电高频(2kHz～50kHz)振动台上,首次在国内外实现了(1nm～500nm)振幅范围内的纳米级振动传感器灵敏度幅值和相移的测量。中国计量科学研究院(NIM)与德国物理技术研究院(PTB)在10Hz～10kHz范围内开展的标准加速度计灵敏度幅相特性国际双边比对验证了国家基准的测量不确定度。     

中俄在250 Hz～200 kHz频段的水声声压比对校准

2009年9月至2010年6月,利用B&K 8104和TC 4033水听器作为比对校准用标准水听器,杭州应用声学研究所和俄罗斯国立物理技术与无线电工程测量研究院之间开展了250 Hz～200 kHz频段水声声压的比对校准。尽管中俄双方所使用的测量方法、校准技术和测量装置不同,但双方的校准结果非常一致,最大的偏差只有0.36 dB。经中俄双方专家讨论和分析后一致认为,两个部门在该频段内校准水声声压所采用的测量方法和校准技术是正确的,测量装置给出的校准结果是精确、可靠的。     

Comparing hydrophone calibration results for Russian and Chinese standards

Russian and Chinese national standards have been compared by exchanging hydrophones for calibration in the frequency range from 1 Hz to 630 kHz. The results agree very closely, which confirms that the estimates made of the errors in the two standards are reliable. Deceased. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 63–67, June, 2000.     

Amplitude and phase calibration of hydrophones by heterodyne and time-gated time-delay spectrometry

Two methods for the amplitude and phase calibration of hydrophones based on time-delay spectrometry are presented: a time-gating technique and heterodyne frequency conversion that allows the phase-locked (i.e., coherent) detection of hydrophone signals. Amplitude and phase of the hydrophone sensitivity are obtained in the frequency range 1-20 MHz. In addition, to show the broad-band capabilities of the methods, amplitude values are measured between 4 and 50 MHz.