摘 要

随着21世纪的到来，全球科技迅猛发展，如今的科学技术已经上升到一个崭新的平台，其中微型计算机和软件技术的发展尤为突出。就传统仪器而言，虽然近年来它的仪器精度愈来愈精确，其性能愈来愈完善，其功能愈来愈强劲，但是总体上来说仍然没有脱离手动式操作以及单独使用的模式。传统仪器工作方式单一，功能比较固定，加工工艺较复杂，其制造与生产的水平要求也非常高。而虚拟仪器，作为一项在20世纪80年代兴起的新技术，其在处理能力方面、智能科技化方面、操作实用性方面等与传统仪器相比都具有非常明显的优势，发展至今已成为现代仪器仪表发展的重要方向。它的应用极其广泛，涉及到教育与培训、规划与设计、建模和仿真等各个领域。

如今NI公司提供的数据采集设备虽然在操作性与性能方面都非常优秀，但是价格过于昂贵，并且构建信号分析系统的成本也较高。计算机声卡的A/D转换性能优越，不仅技术成熟，而且与LabVIEW强大的数据采集与处理功能相结合，可以构建出性能卓越价格低廉的数据采集系统与发生系统。

基于上述较全面的分析，本文用计算机声卡替代传统采集卡作为硬件，在LabVIEW平台上设计出一个信号分析系统（虚拟示波器），然后在信号分析采集实验中进行应用与调试。其主要研究工作包括以下三个方面：

(1) 提出采用计算机声卡作为数据采集设备来构建虚拟音频信号分析系统并应用在教学实验的设想方案。通过对计算机声卡性能的分析以及对各高校实验室现状的调研考察，全面探讨和分析了由计算机声卡组件可用于实验教学的信号分析系统的可行性与必要性。

(2) 构建出基于LABVIEW的音频信号采集分析虚拟系统。在LABVIEW平台上设计开发的音频信号采集分析系统，具有信号采集、信号分析、波形显示、波形存储以及数据文件再分析调用等功能，分析解决了设计与实验环节中所遇到的问题。

(3) 对所提出的设计方法进行了大量的仿真实验与反复的调试，根据所得出的较为精确的实验结果证明了信号分析系统设计的合理性与可行性。

根据基于LabVIEW的信号分析系统设计出的虚拟数字存储示波器总体上包含数据的采集、触发控制模块、波形的存储与回放、滤波等模块，具有许多普通示波器所没有的优点，如波形存储为数据文件进行永久保存与随时调用数据，进行波形实时演示等。不仅成本低廉，而且可以应用环境噪声的监控、语音的准确识别和实验室测量等各个领域。因此，用计算机声卡构建性能卓越价格低廉的数据采集系统与发生系统是切实可行的。

关键词：LabVIEW；计算机声卡；虚拟示波器；虚拟仪器；信号分析系统

Abstract

Today, with the coming of the 21st century, the global technology development of science and technology has risen to a new platform, especially microcomputers and the development of software technology. In recent years, as far as the traditional instruments was concerned, although its instrument accuracy was more and more precisely, and its function become more and more perfectly. On the whole, it was still not out of the manual operation and the alone mode. The operating mode of traditional instruments is single and its function is more fixed, the processing is also complicated, the level of manufacturing and production requirements is very harsh. The virtual instrument, as the rise of new technologies in the 1980s, in terms of processing power, intelligent science and technology, operation practicality and so on compared with the traditional instruments have a very distinct advantage, it has become an vital direction for the development of modern instrumentation. Its wide range of applications related to education and training, planning and design, modeling and simulation, and other fields.

Now the data acquisition devices was provided by NI Corporation in operational and performance are very advanced, but the price is too expensive, and the cost of signal analysis system building is too costly. Computer's sound card A/D conversion performance was so superior, not only the technology is mature, but also combined with the LabVIEW powerful data acquisition and processing functions, you can build a performance inexpensive data acquisition system and the occurrence of system.

Based on the more comprehensive analysis, computer sound card instead of the traditional acquisition card as the hardware, a signal analysis system designed in the LabVIEW platform, then collected in signal analysis and debugged experiments for application. The main research work includes the following three aspects:

1^st Proposed to use the computer's sound card as data acquisition devices to build the virtual audio signal analysis system and application scenarios in the teaching experiment. Through the analysis of the performance of the computer sound card as well as the status of each university laboratory investigations and studies, comprehensive study and analysis of the feasibility and necessity of the components of the computer's sound card can be used for signal analysis of the experimental teaching system.

2^nd Constructed based on LabVIEW virtual audio signal acquisition and analysis system. Audio signal acquisition and analysis system designed and developed in the LabVIEW platform, with signal acquisition, signal analysis, waveform display, waveform storage, and data files reanalysis calls and other functions, to analyze and solve the problems encountered in the design and experimental aspects.

3^rd On the proposed design method of a large number of simulation experiments with repeated commissioning, according to the results of a more precise experimental results prove the rationality and feasibility of the signal analysis system design.

Contains data acquisition, signal analysis system based on LabVIEW virtual digital storage oscilloscope overall design waveform operation, waveform storage and playback, filtering module, with the advantage that ordinary oscilloscope has not, for example waveform stored as data files for permanent preservation and any time call data. Not only the cost is inexpensive, but also can be applied to the exact environmental noise monitoring, voice recognition and laboratory measurements, and other fields. Therefore, it is feasible to build inexpensive performance data acquisition system and the occurrence of system computer sound card.

Keywords: LabVIEW; computer sound card; virtual oscilloscope; virtual instrument; signal analysis system