Research On Multifunction Virtual Instrument

Measuring instruments is indispensable in industry, education and research development. To build a measurement system, we should use two traditional independent instruments, one is for wave generating and the other for signal acquiring, but there is a problem, he two instruments can not be worked synchronized, and also the are not flexible or convenient. To solve these problems, this paper described a multifunction virtual instrument, which base on the concept of virtual instrument. This multifunction virtual instrument integrated signal acquisition function and waveform generating function, and we can use just one this instrument to build a measurement system instead of two with respect to the traditional measure instruments.This paper designed such a multifunction virtual instrument. It is communicating with a computer by the USB interface, so that customers can use the application program on the computer to control the instrument. This multifunction virtual instrument has a complete signal acquiring input tunnel and complete waveform generating output tunnel, in addition , these two tunnels can work synchronized and simultaneously. The whole structure of this multifunction virtual instrument is like this, to use Field Programmable Gate Array (FPGA) as the nucleus of signal acquiring tunnel and DSP Digital Signal Processor(DSP) as the nucleus of waveform generating tunnel, and the two nucleus coordinate by interrupt signals. This structure makes the signal acquiring function and waveform generating function independent but also corporative.Based on this structure, this paper explains the realization of the multifunction virtual instrument in three department:(1) Hardware design: Chapter 2 described the whole structure and hardware design of USB interface module, signal acquiring tunnel and waveform generating tunnel and also analysis the filer module.(2) Software design. Chapter 2 to chapter 5 discussed the application program on computer and USB interface software, FPGA program and DSP program. This paper also compared several different waveform generating methods by DSP.(3) Experiment and error analysis. Chapter 6 tested and verified the data acquiring and signals generating function, and also analyzed the error headstream and give some solving methods.