Research On The Method Of Error Analysis Of Virtual Istrument System

Testing and measure are indispensable means for human beings to understand the objective things in the nature and to quantify the phenomena of these things in order to see through the essence. And measuring instruments are essential tools to realize testing and measure. As the advanced delegate of measuring instruments virtual instruments which are the outcome of tight combination of computer software, hardware and bus technology preserve good characteristic of measure. The core of virtual instruments is to realize measuring function by means of software. Errors are inevitable in all the stationary and dynamic measuring process which prevents us to get the real value of the measured quantity directly. Nowadays technologies develop fast and people demand a higher precision for products. Measuring technology is also expected to achieve a higher accuracy. Hence, to research into the errors of measure and measuring system in order to diminish and even eliminate errors, enhance the precision of measure is necessary. When measuring, virtual instruments are inevitable to cause error damaging the precision of measuring results. However, a whole system to evaluate errors for virtual instruments is not available currently. Therefore, to research into the error of virtual instrument system and educe the error analysis and modification methods is of profound theoretical and practical value. The paper researches deep into mechanical measuring theory, systematic error analysis and synthesis method, constitution of virtual instrument system, error of each subsystem, error description and modification of virtual instrument system and so on. The detailed work and outcomes are as following: 1) It discusses the principle of virtual instrument and its error, carries through innovative systematic researches on error analysis and modification method for virtual instrument system. 2) According to the mechanical measuring systematic error constitution theory and based on the analysis of virtual instrument systematic construction, it researches into the errors of each virtual instrument component, and gets the error analysis and modification method of sensors, data acquisition system and virtual instruments'software. 3) It researches into the virtual instrument systematic error transfer and synthesis using mechanical measuring theory and theories and methods of error transfer and synthesis in error theory. Based on the analysis of errors of each virtual instrument component, it generalizes the error constitution formula of virtual instrument systems and gets the uniform error description and analysis method for virtual instruments. 4) It takes the advantages of the idea that the core of virtual instrument technology is to replace or partly replace hardware with software and proposes the error modification method: (1) use software to implement the function of hardware to those hardware which easily cause error or whose errors are too high; (2) design software to modify the errors of hardware which can't be replaced by software. 5) It provides example for error analysis and modification of virtual instrument system. It discusses the error analysis and modification of virtual noise analyzer and virtual ECG analyzer.