The Research Of Data Processing System Based On Virtual Instrument

ABSTRACT:The traditional analysis method of railway signal is using a outside spectrum analyzer to acquire track circuit signal and using a indoor tape recorder to analyze these track circuit signal. However it is incovenient for this method to store and analysis data, and it is also hard to realize application change and migration. Therefore, it is greatly meaningful to design data processing system which is flexibly, portably and powerfully to execute analysis and process. This system can realize data acquisition and processing, improve the efficiency of signal processing. So it has great practical significance to propose the data processing systems based on virtual instrument.The main works of this thesis are as follows.Firstly, the background and significance of the data processing system, definition, characteristics, researching status and system structure of the virtual instrument are introduced.Secondly, overall design of the data processing system is proposed from hardware and software. The LabVIEW software is selected as the system’s development environment. According to the requirements of the system, PCI bus scheme was chosen from five kinds of bus schemes such as PCI、USB、IEEE1394. In addition, the following works are completed which are the selection of data acquisition cards, the analysis of signal generator and the parameter standard of data logger, the wiring mode comparison of input signal.Finally, the software system is presented which is divided to several levels. Four function modules are constructed such as the data acquisition module, signal processing and analysis module, data storage and display module, the mixing programming module of LabVIEW and MATLAB. And some examples are used to demonstrate the related function of the data processing system which are the acquisition of railway signal, the digital signal reading, signal’s analysis and processing, the wavelet transform based on mixed programming. All the modules can operate well.In conclusion, a data processing system is built based on virtual instrument in this thesis. The system realizes the acquisition, reading, time and frequency domain analysis of the railway signal and other basic function. And the monitoring of pulse singular point is also realized through mixed programming with LabVIEW andMATLAB.