Design And Realization Of Virtual Frequency Spectrum Analyzer

The virtual analyzer of frequency spectrum has combined the technology of virtual instrument, spectrum correcting and software programming. With data acquisition system, the experiment data are put into the master computer, analyzed and measured by the virtual instrument. The results are transmitted into the monitor or file. Involved the topic of designing and realization of virtual frequency spectrum analyzer, the theories of frequency spectrum analyzer and the realizing methods of the instrument functions are researched. The problems during designing software are analyzed in detail, and the ways of solving these problems are introduced. The virtual frequency spectrum analyzer reached the A class standard about instrument of analyzing power harmonic.First of all, the hardware structure of virtual instrument is introduced. The difference between virtual instrument and traditional instrument is compared. The character of HP-VEE is summarized and some different computer software platforms are compared.Then, the basic theories of software designing are introduced. The arithmetic and program for designing and realizing the function module of the virtual instrument is wrote up in detail. On this basis an application software system of virtual frequency spectrum analyzer is developed.It is emphasized on the problems of signal analyzing in frequency-field and ways of solving these problems. In order to make the analyzing results of virtual instrument more accurate, the spectrum correcting technology is studied. After analyzing three existing methods for phase difference correcting on discrete spectrum, it is recommended to correct the spectrum by the first phase difference correcting method.Finally, in combination with VXI instrument the software system is debugged. All functions of the system are tested through using standard signals. The design aim is achieved and the practicability is tested and verified.