The Design And Realization Of Virtual Oscilloscope

With the rapid development of all kinds of high and new technology, limitations of function, expensive price, long update cycle on traditional instruments have become obvious. Therefore, Virtual instrument has been gradually accepted by people because of its strong expansibility, short development cycle and high performance advantages.Virtual instrument is mainly composed of hardware and software. This multifunctional virtual oscilloscope is designed based on object-oriented Visual Basic 6.0 software platform and high speed data acquisition card and computer hardware platform. The designed oscilloscope realized the basic function of traditional oscilloscope and added the data saving-reading function, at the same time, it possesses friendly interface, simple operation and strong extensibility, low cost etc.Firstly, this paper elaborates the research background, significance, the concept and research progress of virtual oscilloscope in the domestic and overseas.By comparing the principle of traditional oscilloscope and virtual oscilloscope, the technical indicators and acquisition technology of virtual oscilloscope are studied.Secondly, the overall design of virtual oscilloscope is described in detail: Hardware design part mainly introduces that the fast data transmission and relatively low cost PC- DAQ plug-in model is chosen by comparing the five kinds of the composition of the virtual instrument. Then PCIe9801 Data Acquisition Card is selected; Software system design part describes three modules of the virtual oscilloscope system: driver, operating system and development software, the three modules were studied; Functional framework is the "skeleton" of the virtual oscilloscope, it introduces oscilloscope software modules.Thirdly, the focus of this article is the detailed Software algorithm, software is composed of six modules: data collecting module, Fast Fourier Transform Algorithm(FFT) module, data saving-reading module, frequency domain waveform display module, time domain waveform display module and parameter processing display module.Finally, three groups of experiments were set. The sine wave, triangular wave and square wave signal are respectively tested in traditional oscilloscope TDS1002 and virtual oscilloscope. The results show that the waveforms changes of virtual oscilloscope almost matches the Tektronix traditional oscilloscope TDS1002’s in time domain and frequency domain, Therefore the virtual oscilloscope software system in this paper can be used in the subsequent study of measurement and control instrument.