Virtual Instrument Technology Research

The project presents a novel way to develop a virtual frequence -peculiarity-measuring instruments system based on the "Virtual Instruments" thought and the frequence peculiarity analyzing theories. The aim of the project is in definite condition of hardwares, developing a quite applied virtual frequence -peculiarity-measuring instruments system on the platform--LabView,which is offered by the NI Company .This system includes creating and controlling frequence-scanning signal,datas acquiring and frequence peculiarity analyzing three main modules, and some extended modules.Firstly, from the point of view of basic functions ,the paper briefly introduces the collectivity design scheme and relational technology parameters.Following that, the paper simply introduces how to building the hardware flatform of system,and gives the implementing diagrams.The emphases in the paper is the software designing and implementing in the system.In this section, the basic principle of frequence-scanning is discussed at first, including the function express for the dynamic peculiarity of a system, the ways to test the peculiarity and the producing of invariable-magnitude sine wave,etc.For the wide range of frequence-scanning, the system adopts shift undersampling technology in order to reduce the sampling rate in the course of datas acquisition, ulteriorly,the dynamic peculiarity of A/D is also tested. In the section of frequence peculiarity analyzing,the paper detailedly discusses tow kinds of magnitude estimate arithmetics, error analysis, precision improveing arithmetics,magnitude "soft-equilibria" arithmetic,etc.ALL those arithmetics and ways improve the veracity and precision of the frequence peculiarity test, which is also the difficulty and innovation in the paper.At last, the paper studies how to actualize the displaying technology,long-distance measure and control, datas store and print functions,etc.