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In order to prospect deep geological structure, low natural frequency geophone is needed. Traditionally, low natural frequency (less than 10Hz) of geophone is acquired by increasing its volume of coil or magnetic body. But that makes it too heavy to be widely used in oil seismic exploration. This manuscript introduces a new method to broaden the low frequency of geophone without changing its structure...
Human proximity sensors are currently being employed in a variety of applications such as individuals' safety, touch-less interfaces, securing valuables, etc. Especially, 3D types are more attractive as they offer robust and accurate detection results. Popular technologies for implementing such sensors include infrared, acoustic, capacitive, and RF techniques. Implementation cost, system complexity,...
In this paper an approach of imitating the periodically varying electrical bioimpedance of human trunk in case of breathing by using a field effect transistor is presented. The principles of creating a simulation model and preparing a prototype of electronic measurement device, are described. The experiments are presented and the results are compared concerning the change of channel resistance of...
The paper presents a design of a four way signal splitter working in L frequency band, for standard GNSS (Global Navigation Satellite Systems) signals. These splitters are used when more than one receiver has to be connected to one signal source, like an antenna, a signal distribution socket or a test signal generator. The advantage of the solution is realization by a PCB structure, without need of...
High impedance faults (HIFs) are part of the most common faults in distribution power system. The randomness, non-linearity and unstable nature of these faults have resulted in false detection and a growing concern, due to the involvement of electrical arcs. Contrary to typical power system faults, HIFs are more likely to result in casualties and therefore, are treated with grave importance. Low current...
This paper presents a wide bandwidth power divider using Stepped-Impedance Resonator (SIR) impedance matching structure. The SIR structure with a short-end stub is proposed to obtain matching to separated modes thus wide bandwidth response is achieved. There are two resistor and a capacitor in series instead of single resistor added between two output ports to improve the isolation. An experimental...
The amplification of low signals from inductive transducers is not an easy task. Existing integrated amplifiers are good enough but in some applications the requirements are for better signal to noise ratio and high gain. For example the LT1028/LT1128's voltage noise is less than the noise of a 50Ω resistor. Here we are discussing the practical aspects for designing an ultra low noise preamplifier...
CAN is becoming the bus of choice for many space applications. The severe −2V to 7V common-mode and −3V to 16V failure tolerance requirements of the CAN bus driver have restricted its implementation to commercial high-voltage processes with transistors tolerant to voltages above 16V. These transistors experience sensitivity to SEGR and SEB radiation events and have led to the limited diffusion of...
High frequency measurements from 3 to 15 GHz of chip-resistors are reported in this paper. The chip-resistors under test have been mounted in the gap of the microstrip line in two ways: with the resistive layer up («wrap around») and with the resistive layer down («flip chip»). The impedance of chip-resistors depends on its mounting method. Flip chip mounting method reduces the imaginary part of impedance:...
This paper discusses development of a fractional order resonator (FOR) using a single fractor, a capacitor and a resistor. The said fractor is an obtuse angle type inductive fractor and inclusion of such fractor makes the Q-factor of this FOR infinite (theoretically). Besides, the proposed FOR is tunable; varying the fractance, the resonating frequency can be tuned. Design, simulation and hardware...
Breakthroughs in power electronics devices enabled the utilization of the IGBT as the main power switch in AFE converters and enabled the emergence of the fully controlled Active Front End, “AFE”, and low input harmonic solution. This solution employs voltage and current control loops and switching with relatively high switching frequencies of greater than 2 KHz in most applications. The AFE converter...
Insulated Gate Bipolar Transistors (IGBTs) will soon be replaced by wide band gap devices (SiC and GaN) as the choice for power semi-conductor switch in Voltage Source Inverters. These devices have extremely fast rise time and fall time compared to IGBT devices. The high dv/dt of PWM outputs create excessive voltage stress in the insulation system of AC motors due to voltage reflection issues associated...
Laser diodes are used in broadband communications including the radiofrequency range. Broadband design of a laser diode bias circuit is presented. The biasing circuit must have a high input impedance for radiofrequency signals, in order to prevent them from entering the DC power supply. The desired frequency bandwidth of the biasing circuit is up to 5 GHz. In this paper, two different biasing circuit...
A versatile multi-amplifier flicker noise measurement system with various programmable configurations was developed for accurate and fast on-wafer flicker noise measurement. The noise system performance, which includes system resolution, corner frequency and bandwidth, are thoroughly analyzed by correlating various system configurations, such as selection of LNAs, LNA noise floor, DUT output impedance,...
A novel equal power divider working at dual frequencies was investigated in this letter. The proposed divider features good isolation, flexible design parameters and frequency ratio. Rigorous theoretical analysis and simulation results are also presented.
Microelectrode arrays have extensive applications in the biomedical field. These applications range from the study of the influence of drugs in cell cultures to neuro-implants for attenuation of diseases, such as Parkinson's disease and epilepsy. The main block of the analog front-end attached to the MEA is the bioamplifier that amplifies biomedical potential signals. Different designs for this block...
There has been a push for a greater number of channels in implantable neuroprosthetic devices; but, that number has largely been limited by current hermetic packaging technology. Microfabricated packaging is becoming reality, but a standard testing system is needed to prepare these devices for clinical trials. Impedance measurements of electrodes built into the packaging layers may give an early warning...
Measurement of respiration rate is very important in the field of medical. Now a days bioimpedance has been used in many of the medical applications. Breath rate monitoring with good battery life is not yet available for continuous monitoring. Challenge includes making the system easily wearable, reducing noise level, good accuracy, good battery life and cost effective. The objective of this work...
The current source is one of the most important circuits in Electrical Impedance Tomography (EIT) systems. It should be able to supply low current (1 mA) at 10 kHz–1 MHz and can support load between 100 Ω–10 kΩ. Moreover, it must have output impedance greater than 100 kD. In this study, we evaluated an Enhanced Howland (EH) and Triple Op-Amps (TOA) current sources with two different op-amps namely...
This study proposes an estimate method of the element's soft-fault parameter value (SFPV) based on steady-state node-voltage when a soft-fault of occurs. The method defines a radial direction deviation angle (RDDA), two element position coefficients (EPCs), and a parameter deviation coefficient (PDC) for a soft-fault element, and then utilizes the impedance circle to set up an equation among a RDDA,...
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