Search results for "Virtual instrument"
showing 5 items of 15 documents
Real-time acquisition of wideband signals data using non-uniform sampling
2009
Wideband signal acquisition often faces a problem of bulk data recording. It is a critical factor in real-time systems. The paper discusses an approach that deals with this problem incorporating Digital Alias-free Signal Processing and Virtual Instrumentation technologies. Such combination is advantageous for real-time applications and useful in the development of measurement and software defined radio systems. Non-uniform sampling technique allows considerably decrease the data of wideband signals so, that they can be transferred in real-time to a typical PC through high-speed PCI Express communication interface. The experimental prototype system has been developed and obtained results are…
Approaches to evaluate the virtual instrumentation measurement uncertainties
2002
This paper deals with the metrological characterization of virtual instruments. After a brief description of the features, the components and the working principle of the virtual instruments and the various uncertainty sources are analyzed. Then, two methods to evaluate the uncertainty of the measurement results are presented: a numerical method simulating the physical process of the A/D conversion, and an approximated theoretical method applying the "uncertainty propagation law" of the "guide to the expression of uncertainty in measurement." With both methods, the combined standard uncertainty of the measurement result is obtained, starting from the standard uncertainty generated by each s…
Measurement uncertainty estimation of a virtual instrument
2002
The law of uncertainty propagation is applied to a PC-based virtual instrument. According to the "guide to the expression of uncertainty in measurement", the measuring model and the various sources of uncertainty have been taken into account. The expressions of the combined output uncertainty in various basic digital signal processing blocks, are obtained starting from each input sample absolute accuracy, without taking into account the parameters which regard the overall behavior of an acquisition board, such as the effective number of bits. In order to verify this procedure, the results obtained by means of the theoretical analysis, are compared with the ones obtained from numerical simul…
Electrical distribution substation remote diagnosis and control system
2014
This paper presents the conception, design, set up and realization of a prototype system for telemanagement of a MV/LV substation. The prototype has been developed according to the current standards. This system allows to monitor the status of the MV/LV substation box, of the medium voltage equipment, of the transformer and of the low voltage equipment. In particular, the system acts when some specified events occur. The prototype has been realized by using a DAQ; the software that implement the telemanagement system has been developed in LabVIEW environment. The system allows a remote monitoring of the quantities of interest that is carried out using the TeamViewer software able to establi…
ISFET drawbacks minimization using a novel electronic compensation
2004
Ion sensitive field effect transistor (ISFET) and membrane field effect transistor (MEMFET) have some drawbacks related to: long-term drift, hysteresis and thermal drift. These factors limit the accuracy of ISFET/MEMFET based measurements systems, specially for continuous or long period measurements. Due to its accuracy, repeatability and easy-to-use features, electronic instrumentation systems are the best tools to design ISFET/MEMFET based measurement systems. A well-designed hardware and a qualified virtual instrumentation software are the key factors to overcome and compensate hysteresis, thermal and long-term drifts ISFET/MEMFET limitations. The paper is dedicated to show an instrument…