摘要：虚拟仪器技术的提出和发展标志着二十一世纪自动测试与电子测量仪器领域技术发展的一个重要方向。该技术是在通用的计算机平台上定义和设计仪器的测试功能，使用者在操作这台计算机时就像在使用一台自己设计的专用的传统电子仪器。操作人员可通过友好的图形化用户界面和图形化编程语言来控制仪器的启动、运行和结束，完成对被测信号的数据采集、信号分析、谱图显示、波形图显示、故障诊断、数据存储以及控制输出等功能。
在虚拟仪器系统中,硬件解决信号的输入和输出,软件可以方便地修改、改变仪器系统的功能,以适应不同使用者的需要。其中信号的输入部分一般使用数据采集
卡实现。商用的数据采集卡具有较大的通用性,但其价格昂贵,在具体的应用场合,有些功能可能并不实用。普通声卡,具有16位量化精度,数据采集频率为44 kHz,完全可以满足特定应用范围内数据采集的需要,个别性能指标还优于商用数据采集卡,而价格却为商用数据采集卡的十几分之一甚至几十分之一。
论文利用普通声卡做采集卡,利用美国NI公司的虚拟仪器软件LabVIEW做开发平台,设计实现了一个虚拟示波器。该系统能够正确采集声卡设计频率范围内的信号,实现了基本示波器的测量功能和频谱分析功能,可以用来测量音频范围的信
号。
关键字：LabVIEW； 声卡； 数据采集； 虚拟仪器
Abstract：The proposal and development of virtual instrument technology marks the directionof the automatic test and electronic measurement at 21st century. This technology defines in general computer platforms and designs the test function of instrument, when users operating the computer like using a traditional electronic instrument. Operators can control to start, operate and end it through graphical user interface and graphical programming language, and then accomplish data acquisition, signal analysis and spectrum chart shows, waveform figure shows, faults diagnosis, data storage and output control, and other functions of the measured signal.
In virtual instrument system, hardware solve the problem of input signal and output signal, the software can be easily modifiing, changing the function of instrument system, in order to adapt to the needs of different users. Part of the input signal is generally realizing by the data acquisition card. Commercial data acquisition card is more general, more expensive but some functions may be unpractical. Ordinary soundcard, with 16 quantitative precision, 44 kHz data acquisition frequency, can meet the need of data collection in specific application range, and the individual performance index is also better than commercial data acquisition card, but the prices of commercial data acquisition card is more expensive.
This paper designes and realizes a virtual oscillograph with common audio card and LabVIEW virtual instrument software. The system can correctly acquisite the singal and realize the functions of measurement and spectrum analysis as basic oscilloscope.
Key words : Virtual Instrument; Labview; Signal Generator
