The Design of a Frequency Characteristic Test Instrument Based on VI Technology

摘要

Virtual Instrument(VI) is the newest development orientation of the instrument.It becomes the important field of information technology. This task brings forward a method to design virtual frequency characteristic testing meter based on "Virtual Instrument" idea.It discusses the design of the frequency characteristic test meter from software and hardware aspects in detail. The system included the three modules such as DDS signal produced and controlled,data acquisition and frequency characteristiC analysis.Firstly this paper introduces the system design scheme,then it introduces the DDS signal source,in this section DDS is realized by the method of combining fpga with MCU. Then it introduces the data acquisition based on PXI bus and NI software LabVIEW. At the same time it introduces the data acquisition flow and frequency characteristic analysis.Finally this paper provides the example of testing the low 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 newstyle test instrument can well satisfy science research and engineering design by its novel,vivid curve displaying.