【作者】 陈品；

【导师】 陈心昭；

【作者基本信息】 合肥工业大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 本文在对声强测量理论和现有声强测量系统全面深入分析的基础上,在国内外首次提出基于数字式声强探头的声强测量系统。与传统模拟式探头结构不同,数字式声强探头优化了前端调理电路,并高度集成了基于双核SOC框架的数字电路和闭环校准控制电路。手柄对外直接输出校正后的声强窄带谱、CPB谱和总声强级等；外接功放和扬声器,可组成声强探头自校准系统。该设计方案改变了常规声强测试系统的组成结构,解决了模拟式p-p声强探头存在的诸如接口不通用、易受干扰、并联困难、测试系统成本高等不足。全文从硬件设计、声强算法和误差、软件研制、校准方法和精度考核等几个方面对基于数字式声强探头的测量系统做了全面细致的研究,主要内容如下：第一章回顾了声强测量技术的发展历史和研究现状,对声强测量系统的分类、特点和发展趋势进行了讨论,指出目前国内外相关产品存在的不足,提出一种基于数字式声强探头的设计方案,明确了本文的工作内容。第二章介绍了连续介质的三个基本方程,对声能、声能(流)密度及声强之间的关系进行了分析,讨论了P-U、P-P两种声强测量方法的特点和双传声器时域、互谱声强算法,对瞬时声强、有功声强和无功声强的误差公式进行了推导,并分析了δPI、δPIO、Ld、F2、F3等重要声场指数的特性和物理意义。第三章从前置放大、程控增益、高低通滤波、A计权、SOC数字电路、扩展模块等几个方面,对硬件电路的参数计算和实现方法进行了详述,分析讨论了数字式声强探头硬件系统中影响测试精度的各个因素,提出了可获得良好声强探头精度的硬件设计方法。第四章深入分析了数字式声强探头算法中产生误差的主要因素,研究了数字式声强探头算法中测量噪声和量化噪声、谱干涉和能量泄露、频率误差和相位补偿等因素对声强计算精度的影响,提出了一种适用于数字式声强探头的分段窄带谱和CPB谱计算方法,并对该算法可能产生的误差进行了研究。第五章研究了数字式声强探头校准方法和精度。基于传声器声学模型,分析讨论了均压孔暴露和未暴露声场时,其低频灵敏度对声强探头相位校准精度的影响,建立了驻波声场中面对面式p-p声强探头测量误差模型。分析比较了消声室内垂直法和平行法两种探头相位校准方式,针对数字式声强探头提出了一种现场环境下基于离散扫频的平行法校准方法,计算出现场环境下保证校准精度的条件,可确保研制的数字式声强探头在普通环境下实现高精度的相位校准。第六章介绍了Windows平台下数字式声强探头上位机应用软件的开发过程。对应用程序主体框架、不同通讯模式下的运行机制、各种应用功能的控制面板和通讯协议进行了详细讨论。第七章在消声室内对数字式声强探头的A计权精度、声压-残余声强指数、声压频响、声强频响和指向性等主要性能指标进行了测试,通过B&K4205标准声功率源和国产2XZ-4A型旋片真空泵在不同声学环境下的对比性试验,检验数字式声强探头的精度。最后介绍了使用数字式声强探头进行噪声源定位的两个工程应用实例,进一步对探头的性能和可靠性进行考核。第八章对全文的工作与创新进行了总结,提出可进一步开展的研究工作。更多还原

【Abstract】 After reviewing and analyzing the sound intensity measurement theory and the existing sound intensity measurement systems thoroughly, in this dissertation a sound intensity measurement system was first proposed based on a digital sound intensity probe. Compared with the traditional analog, the front-end conditioning circuit is optimized and both a digital circuit based on SOC framework and a closed-loop calibration control circuit are highly integrated in the digital sound intensity probe. The proposed measurement system can directly output the corrected narrow band spectrum of sound intensity, the CPB spectrum as well as the total sound intensity level. By connecting external amplifier and speaker, the self calibration system of sound intensity probe can be also constituted. The design of the proposed measurement system based on digital sound intensity probe changes the structure of conventional sound intensity test system and resolves the deficiencies of analog p-p sound intensity probe such as bad general characteristics of interface, poor anti-interference, difficulty in parallel and high cost of test system.In order to develop a sound intensity measurement system based on digital sound intensity probe, the problems including hardware design, measurement algorithm and error analysis of sound intensity, software development, calibration method and measurement precision were studied in-depth in this dissertation. The main contents of the dissertation are as follows:In chapter one, the development history and the current status of measurement technique of sound intensity were reviewed; the classification, the characteristics and the development trends of measurement systems of sound intensity were discussed. Then the deficiencies of related products were pointed out and the main research contents of this dissertation were determined.In chapter two, three basic governing equations for continuum were introduced and the relationships among acoustic energy, acoustic energy density and sound intensity were analyzed. The characteristics of sound intensity measurement methods based on both p-u and p-p were discussed. The time-domain algorithm and the cross-spectral algorithm based on two microphones were also discussed. The error equations of instantaneous sound intensity, active sound intensity and reactive sound intensity were derived. The characteristics and physical meaning of important factors such as δPI,SPI0,Ld,F2and F3were analyzed.In chapter three, the parameter calculation and the implementation of hardware circuit were first described detailedly from the points of preamplifier, programmable gain, high and low pass filter, A-weighted pressure, SOC digital circuits and expansion module. Then several factors that influence the measurement accuracy in hardware of digital sound intensity probe were discussed and analyzed. Finally a design method of hardware system of sound intensity probe was proposed to get good measurement accuracy.In chapter four, the main factors generating errors in the digital sound intensity probe algorithm were analyzed first. Then the way how the factors of measurement noises, the quantitative noises, the spectral interference, the energy leakage, the frequency error and the phase compensation influence the calculation accuracy of sound intensity in the digital sound intensity probe algorithm was investigated. Finally a calculation algorithm for piecewise narrowband spectrum and CPB spectrum of digital sound intensity probe was proposed and the errors that may be generated in the proposed algorithm were also investigated.In chapter five, the calibration method and the accuracy of the digital sound intensity probe were investigated. Based on the acoustic model of microphone, the influence of low-frequency sensitivity to the calibration accuracy of the phase of sound intensity probe were analyzed when the pressure hole was exposed to the sound field and when the pressure hole was not exposed to the sound field, respectively. The measurement error model of sound intensity probe which is p-p and face-to-face was established. Two phase calibration methods of sound intensity probe implemented in anechoic room, vertical method and parallel method, were analyzed and compared. A parallel calibration method was proposed for digital sound intensity probe based on discrete frequency sweeping, which can be used in real engineering environment. By the proposed calibration method, a high phase calibration accuracy of the developed digital sound intensity probe can be achieved in an ordinary environment.In chapter six, the development process of PC application software of digital sound intensity probe was introduced on the Windows platform. The main frame of application, the operating mechanism in different communication modes, the control panel of a variety of applications and communication protocols were discussed in detail.In chapter seven, the key performance indicators of digital sound intensity probe such as A-weighted accuracy, sound pressure-residual sound intensity index, frequency response of sound pressure, frequency response of sound intensity and directivity were tested. The accuracy of digital sound intensity probe was also examined by experiments that compare the results of a standard sound power source (B&K4205) and a domestic rotary vane vacuum pump (Type2XZ-4A) in different acoustic environments. Finally two engineering application examples in which the noise sources were identified using digital sound intensity probe were described.In chapter eight, all the investigations in this dissertation were summarized and the topics that should be studied further in the future were proposed.更多还原