9762 papers found
The paper presents design and basic metrological properties of three thermal AC voltage standards with nominal input voltages 1.5 V, 3 V and 6 V. Each standard is composed of a range resistor connected in series with a single junction thermal converter (SJTC). The AC-DC transfer differences of these standards are calculated in frequency range from 10 kHz to 1 MHz.
The smart grid approach is envisioned to take advantage of all available modern technologies in transforming the current power system to provide benefits to all stakeholders first of all in the fields of efficient energy utilization and of wide integration of renewable sources. Energy storage systems, especially those based on batteries, could help to solve some issues that stem from the use of renewable energy, in terms of stabilizing the intermittent energy production, power quality and power peak mitigation. With the integration of energy storage systems into the smart grids, their...
The cascaded integrator-comb (CIC) filters are widely used as decimators in many applications, such as in delta sigma AD converters to decimate the sampled signal on its output. One problem with these filters is that by increasing its order to improve the signal attenuation in the stop band, worsens the passband response. In this paper we propose a so-called least-squares filters (LSF) based on B-splines to improve that response, compensating for CIC filter drop and flattening the magnitude response of the pass band. We also study the relationship between the CIC filters, otherwise called...
This paper presents a measurement system and energy management for Guanay II autonomous underwater vehicle (AUV). The system performs the measurement, monitoring and control of the state of charge of the batteries, allowing simultaneous charging of all batteries from outside of the vehicle, and a wireless connection/disconnection mode. Considering the type of batteries used in the vehicle, it is used the current integration as methodology for measuring the charge level of the battery. Laboratory and vehicle navigation tests performed have validated the correct operation of the system and the...
Eddy Current Testing (ECT) is a Non Destructive technique widely used in many industrial application fields in which it is very important to detect the presence of thin defects (generally called cracks) in conductive materials. Features of this technique are the cost-effective implementation and the kind of retrieved measured data that make possible estimating geometrical characteristics of a crack as position, length, width and depth. The analysis of these characteristics allows the user to accept or discard realized components then improving the production chain. To accomplish for this...
In this paper the design and implementation of an automatic measurement system for the characterization of power MOSFETs is described. Such system allows to obtain a complete characterization of the MOSFET regardless of the final application, totally automated and thus a fast and cheap response to the industrial requests.
In a measurement context often it is fundamental to verify if two independent measurement processes give origin to the same uncertainty. The comparison between these two uncertainties is important, for instance when we use two or more different instruments. We apply this method to the uncertainty of a digital oscilloscope measuring rise/fall time of a signal. We apply this test to verify this property if it is requested by other important hypothesis tests like that about the difference between the measurand estimators. This technique is also the base to the ANOVA (ANalysis Of VAriance)...
There is a growing interest on measuring time intervals between the J peak of the ballistocardiogram (BCG) and several features of other cardiovascular signals such as the ECG in order to obtain cardiovascular function markers. Nevertheless, possible uncertainty factors involved in these measurements have not been identified and analyzed, which is a necessary step to advance towards standardization in this reemerging biomedical engineering field. In this paper we analyze the effect of the low-pass cutoff frequency and phase characteristic of filters, noise and power line interference on...
This paper presents a new design based on acquisition system of the volcanic seismic data. Mainly, this system is composed of a microcontroller to manage the peripherals, a module to acquire the information of seismic sensor and a module of communications that contains the RF and GPS system. The prototype aims to be a very low power system allowing also working during a complete year.
A nH level mutual inductor has been designed and used as the standard impedance for measuring the equivalent inductance of current shunts. A method has also proposed to measure the mutual inductance against the ac voltage standard and current standard at frequencies up to 200 kHz.