A Frequency Characteristic-testing Instrument Based On VI Technology

Virtual Instrument is the newest development orientation of instrument. It became the important field of information technology. This task brings forward a method to design virtual frequency characteristic testing meter based on "Virtual Instrument" idea. Its aim is to realize frequency characteristic test system using virtual instrument development—LabVIEW provided by the NI Company in the United States and combing the corresponding hardware condition. The system included the three modules such as DDS signal produced and controlled, data acquisition and frequency characteristic analysis.This paper introduces the destination of developing the frequency characteristic testing meter, the features and structure of the virtual instruments based on virtual instruments technology, then it introduces the collectivity design plan, system software and hardware platform construction and provides the realized block diagram. Since then it discusses the design of the frequency characteristic test meter from software and hardware aspects in detail. In this section, firstly it introduces the developing, major technological index, fundamental structure and operational principle of the DDS frequency composed technology, then it introduces the bus selection, test system construction, basic knowledge of data acquisition, acquisition flow and frequency characteristic analysis. It makes certain that it tests by virtual instrument based on PXI bus. Finally this paper provides the example of testing the low pass and band pass RC circuit; constantly it proves this design is feasibility.In a word, this new-style frequency characteristic test meter utilizes fully virtual instrumental technology, newly strongly software function and graphics of computer. This new-style test meter can well satisfy science research and engineering design by its novel, vivid curve displaying.