Design And Development On Virtual Experiment Platform Based On Labwindows/cvi

The core of virtual instrument is that the hardware which regards computer as the instrument is supported, fully utilize intellectual functions, such as computer unique operation, memory, playback, transferring, showing and file management, etc. make it conbine with the PC together and combine traditional specialized function software of instrument. Virtual instrument laboratory builded by virtual instrument has many advantages,such as less investment,short developing period.It can promote development of present engineering test laboratory.This thesis takes LabWindows/CVI as the development platform which is based on the storehouse of ANSI C, through using DLL technology, Sound card driver is developed in Visual C++environment, using the powerful language C++, mainly uses the elementary function of audio in MMSYSTEM.DLL of Windows system with double cache mechanism, realize the collection of real time for the signal of audio frequency through sound card; has digital processing system based on sound card as well as chaotic white noise emulation instrument. Digital processing system based on sound card realized the real-time analysis for tonic train signaling, including the time domain analysis and the frequency domin analysis, and realized functions of wavelet analysis and others to the partial misalignment signal. The time domain analysis including the signal autocorrelation analysis and the mutual correlation analysis; Frequency domain analysis including amplitude frequency spectrum analysis, phase-frequency analysis, FHT analysis. And the filter technique using the IIR filter as well as the Weina filter; Wavelet analysis including functions and so wavelet denoising, wavelet extraction, small wave packet decomposition and so on. Moreover the chaos white noise simulation meter, which is produced by the application chaos theory and have not the periodicity, has the characteristic of parameter sensitive. Finally realized the network service and data network sharing realizes by using the DataSocket technology.This thesis takes LabWindows/CVI as its development environment, It can form independent setup software package and run absolutely deviating the development environment, accordingly, Its setup is easy and has a strong practicability. virtual instruments can be done human-computer interaction by graphical user interface. The method is characterized by easy operation. Through the practical validation, compared by the traditional instruments, the testing efficiency and testing precision of the virtual instruments are much better.It can be widely used in Teaching and Testing, Engineering Signal Analysis and Fault Diagnosis.