【作者】 王晓锋；

【导师】 秦树人；

【作者基本信息】 重庆大学 ， 机械电子工程， 2002， 硕士

【摘要】 音频分析被广泛用于测量各类音频系统的时域特性、频域特性及失真特性等。进行比较完整的音频测试分析需要购置各种价格昂贵的专用仪器，而且需要整合成整套的音频测试系统，这对于普通用户来说存在一定的困难。本文介绍了如何在研究音频分析基本原理的基础上试图将虚拟仪器技术引入到音频分析仪器的设计中来，形成全新的虚拟式音频分析仪。主要的工作步骤及结论如下：(1)分析目前存在的各种音频分析类仪器的功能和各自的优缺点，并结合虚拟仪器的思想提出虚拟式音频分析仪的设计目标。(2)研究音频分析的测试内容和意义及所用到的各种方法。在音频设备的时域特性分析中，阶跃脉冲响应检测是衡量系统性能的重要方法，它反映的是音频设备对于突变信号的响应灵敏度。音频设备对于信号的重放能力是由其频率响应特性来衡量的。分析音频设备的频率响应特性主要有单音信号检测法、噪声冲击检测法和最大长度序列检测法等。其中最大长度序列法在测量效率以及抑制噪声方面有比较明显的优势，因此近来得到比较广泛的应用。谐波失真是音频设备最常见的一种非线性失真，它直接影响到音频设备的重放效果，谐波失真曲线图反映出设备在整个音频范围内的失真分布情况，是衡量设备性能的重要参数。(3)利用软件工程中的结构化思想将虚拟式音频分析仪的设计分为采集、分析、显示、辅助及控制共五个部分，并分别以软件模块的形式加以实现。五个功能模块内部实现不同的功能，外部提供统一的接口，通过相互之间的协调配合形成完整的音频分析系统。(4)通过实测典型的音频设备，即音箱的扬声器单元来检测虚拟式音频分析仪的实用效果，得到扬声器单元的各种音频特性参数。(5)最后从硬件集成化、软件对象化和应用网络化三个方面提出进一步加强虚拟式音频分析仪实用性的设想。 QLVAF-1型虚拟式音频分析仪作为作者自行研究设计的音频分析仪器，提供了丰富的测量及分析功能，包括音频信号的电压及频率测量、音频设备的时域幅值分析、频域幅值分析和失真分析等。用户利用该仪器可以很方便地组建功能强大的音频分析系统，进行各种音频测量分析工作。更多还原

【Abstract】 Audio analysis is widely used to measure time domain, frequency domain and distortion characteristics of various audio system. An all-around audio test and analysis needs all kinds of expensive special instruments, which should be well organized. Obviously, it is not a piece of cake for common user.Based on studying the fundamental theory of audio analysis, this paper puts emphasis on how to import virtual instrument technology into designing audio analyzer, and creates fire-new virtual audio analyzer. The main works and conclusions in this paper are as follows:(1) The existing audio analyzers’ functions and their merits and defects are researched, and the goals of virtual audio analyzer are brought forward combined with thoughts of virtual instruments.(2) The contents, purposes and methods of audio analysis are studied. In Amplitude Analysis in time domain, the step impulse response acts as an important parameter to evaluate the performance of audio device. It reflects the response sensitivity of audio system to sudden changed signals. Audio devices’ performances in playback are evaluated by their frequency response in the whole audio frequency range. There are several widely used methods to acquire the frequency response graph, including single tone method, multiple tone method, noise impulse method and Maximum Length Sequence signal impulse method. The last method, MLS signal impulse, has so obvious predominance in the aspect of decreasing noise as to obtain increasingly wide use. Harmonic distortion is one of the most common non-linear distortions, and it affects the playback performance of audio devices directly. Harmonic distortion graph reflects the distortion distribution in the whole audio frequency range.(3) Using structurization thought in software engineering, the design of virtual audio analyzer is divided into five parts, which are data acquisition, analysis, displaying, auxiliary and control. The five parts are realized in the form of software modules. They provide different functions inside and uniform interfaces outside. They cooperate each other and make up an integrated audio analysis system.(4) The loudspeakers of sound box are tested using virtual audio analyzer, and some audio characteristics are obtained.(5) Finally, the further assumptions are brought forward with three aspects, which are integration of hardware, object orientation of software and network based application.QLVAF-1 type of virtual audio analyzer, which is developed by the authors<WP=7>independently, can be applied to measurement of varied audio devices. The analyzer provides versatile measure and analysis functions to meet the requirement of audio devices, including measure of audio signal’s volt and frequency, Amplitude Analysis in time domain, Amplitude Analysis in frequency domain, analysis of distortion, etc. Using the analyzer, users can make up useful audio analysis system and carry through various audio tests.更多还原