The paper presents an upgraded version of an application of MATLAB web server, one of MATLAB toolboxes, for teaching/learning some selected measurement algorithms important in processing discrete-time signals in measurement. The original version is described in [1] and [2]. The topics included are DFT/FFT (demonstration of DFT basic properties and DFT application in spectrum analysis and detection of week tones close to a strong tone), FIR filters (including the important moving average filter), basic IIR filters and some basics of stochastic signal processing in time domain and amplitude...
The paper analyses effect of windowing a multi-frequency signal on the result of calculating signal parameters based on DFT. Influence of window side-lobes of nearby harmonic signals on the result of computation depends on the on the used window and on the difference in the two components magnitudes and frequencies. There are several other sources of resulting bias and uncertainty of measurements based on such algorithms. These influences are also briefly mentioned. The presented examples concern two methods of estimating RMS value, but the described principle is applicable to all algorithms...
The paper presents the impedance measurement method using a real-life step pulse as a perturbation signal and Laplace transformation as a tool for analyzing the response of the object under test. The method is addressed to explore different technical object (like anticorrosion coatings, gas sensors, ceramics, dielectrics biological tissues etc.) when the measurement time cannot be long. The presented method is known, but is not very popular because of some limitation. The paper presents the influence of the limitations on the accuracy of the equivalent circuit parameters identification.
Vein pattern recognition is one of the newest biometric techniques researched today. While the concept behind the method is quite simple, there are various challenges to be found throughout the design and implementation of a vein scanning device concerning the hardware lighting system and the actual algorithms used for processing the acquired images. In order to keep the scanning errors to a minimum the image acquired from the camera should be almost noiseless and the algorithms should be able to detect the vein pattern in various real life conditions. Many implementations of this method are...
The aim of this paper is to show a determination method for mechanical shocks, using as sensing element an analogical Hall effect transducer. In the first part of the paper there will be enunciated the used physical principle, mentioning the conservation laws of mechanical energy and in following part we will describe the experimental setups and the behavior of the implemented captors. We will also analyze the factors that can generate errors or they can disturb the measurement process. There will be presented the sensors as well as a implementation method of the sensor in complex integrated...
This paper presents an experimental approach on the electrical capacity of an ionization chamber, of a special shape: the electrodes of the chamber are two plan-parallel plates. The distance between the two electrodes can be varied mechanically; in this way, one can obtain also a variation of the sensitive volume of detector. Such a transducer of a special shape and size is very important in the ionizing radiation metrology, because it allows the use of an absolute method for the measurement of the absorbed dose in beta rays beams or fields.
The paper presents modified CNLS impedance spectrum fitting method of parameter identification of technical objects. The number of test frequencies is reduced to the number of parameters and the test frequencies are set according to various criteria. As a test object, the model of anticorrosion coating has been chosen. The simulated identification results are discussed in terms of identification measurement time reduction and method accuracy.
The possibility of using of the IEEE STD-1057 and STD-1241 standards for measurement channel features estimation in operation conditions is discussed. The standards concern the test methods and circuits for the devices containing ADC in laboratory conditions and cannot be simply applied in the instrument under operation conditions. Some remarks concerning the specificity of such conditions and range of applicability of standards are presented. The results of examining of selected test signal sources are discussed.
The paper present a system for management building based a compatible PC computer that communicates through a RS-485 serial protocol with the development board with microcontroller. The development boards are placed on the level of each building floor. These development boards take the signal from sensors placed on the level of each room and achieve the command function based on an independent algorithm, commanding by case the corresponding central heating or cooling plant.
This paper present a virtual instrument using for analysing a electrocardiographical signals. An interesting analisys can be made having on the base the graphical representation of samples series depending on this derivative, using a wavelette transform or fractal analysis.