Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"output impedance"”.
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Hybrid Active Power Filter with Output Impedance Control
… regulation at high frequencies by increasing the output impedance beyond a desired level. This dilemma has been recognized and several topologies have been proposed to overcome this problem. One category is improved passive devices, with the latest involving array capacitors to achieve near-zero …
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Output Impedance Modeling and Measurement of a 28 kW Synchronous Generator
… and in the end, the small-signal d-q impedance model for the SM has been verified by simulations and experiments in the Center for Electronics Systems (CPES) at Virginia Tech. The impedance measurement unit (IMU) was built by CPES. It is designed for measuring three-phase AC power …
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Input filter compensation for switching regulators
… of transient response, audiosusceptibility and output impedance characteristics. These problems are caused mainly by the interaction between the peaking of the output impedance of the input filter and the regulator control loop. Conventional single-stage and two-stage input filters can be …
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Out-of-Loop Compensation Method for Op-Amps Driving Heavy Capacitive Loads
… of an ideal one, particularly those of gain and output impedance. When presented with a capacitive load, such as a MOSFET or ADC, feedback in an op-amp circuit can quickly become unstable. This thesis studies and characterizes an op-amp’s output impedance and how its interaction with this type of …
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Dynamic Performance Analyses of Current Sharing Control for DC/DC Converters
… distributed power systems. To ensure balanced output currents among paralleled power modules, current sharing control is usually necessary.Active current sharing controls with current feedback mechanism are widely used in today's power supplies. However, the dynamic performance of these current …
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Photovoltaic Source Simulators for Solar Power Conditioning Systems: Design Optimization, Modeling, and Control
… (ii) fast transient response-time, (iii) output impedance matching with actual PV generator, and (iv) precise reference generation technique. Throughout this research, two different PV source simulator systems are designed, modeled, and experimentally verified. The design of the first …
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High Performance Digital Control Techniques for Powering Microprocessors
… technique to naturally implement the desired output impedance is proposed. In this technique, Adaptive Voltage Positioning (AVP) is implemented by generating a dynamic voltage reference and a dynamic current reference to achieve the desired output impedance. A dual-voltage-loop control with …
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Design, fabrication and application of a dedicated thick-film hybrid time domain reflectometer
… pulse generator characteristics as well as the output impedance of the unit. The unit is fabricated using standard thick-film hybrid techniques while giving consideration to problems encountered at microwave frequencies. This thesis also presents an overview of time domain reflectometry and its …
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A low-voltage zero-crossing-based delta-sigma analog-to-digital converter
… maintain common-mode level at each integrator output. Correlated level-shifting is used to increase the effective output impedance of gated current sources. The technique was used to design a single-bit 4th-order delta-sigma analog-to-digital converter for audio applications. The prototype ADC …
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Investigation into the impedance and communication requirements for the low voltage distribution line in the high frequency spectrum
… power line network with numerous branches and impedance mismatcheS causing reflections and attenuations during signal transmission, and thus communication signal cannot be sent out or received completely. From this point of view, the power line impedance is a very important parameter in the …
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CMOS/Bipolar current conveyor design and development
… the current follower (mirror) by increasing its output impedance. Several types of current mirror were compared using analytical and simulation methods, using a new generic low frequency transistor model which was used to highlight the differences in impedance between BJT and CMOS current …
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New Multi-Phase Diode Rectifier Average Models for AC and DC Power System Studies
… results. In the frequency domain, the output impedance of a nine-phase diode rectifier is derived, and the sampling effect in the average model is investigated by Fourier analysis. The feeder's impedance before the rectifier is modeled differently in the output impedance in contrast in …
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High performance zero-crossing based pipelined analog-to-digtal converters
… circuits to be made. But at the same time, output impedance of transistors has gone down, as have the power supply voltages, and leakage currents have increased. These changes in the technology have made analog design more difficult. More specifically, the design of a high gain op-amp, a …
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The Investigation and Implementation of electrical Impedance Tomography Hardware System
Electrical impedance tomography (EIT) is a medical imaging technology that provides a tomographic representation of the distribution of electrical impedance within the body. As the electrical impedance varies for different body tissues, it is possible to characterize tissues from the images and to …
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Wideband high-power transmission line pulse transformers
… different geometries with unity input/output impedance. This work demonstrates the design and construction process of a geometric transformer with comparison to simulation and prior art. The focus of this work is on the design, optimization, build and test results of a novel geometric …
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RF energy harvesting using carbon nanotube components
… modeled as an AC Thevenin voltage source with an output impedance of 50 [omega].
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Design of a Low Noise Amplifier for Wireless Sensor Networks
… structures. The LNA needs to have matched input impedance, and at the same time it should amplify the small amplitude input signal without adding too much noise and still have the minimal power consumption. It also needs a good interface with external filters for input and output matching …
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Large-strain piezoelectric actuators using controlled structural buckling
… buckling produces a pronounced nonlinearity in output impedance; the effective stiffness viewed from the output port varies as a function of output displacement, which can be a useful property for those applications where actuator stiffness needs to vary. Buckling is controlled with phased …
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Automatic design tool for robust radio frequency decoupling matrices in magnetic resonance imaging
… matrix seen by power amplifiers with 50 Ohms output impedance is a diagonal matrix with matching 1 (or 0.02 Siemens) at the diagonal. Our tool computes the values of the decoupling matrix via a non linear optimization and generate a physical realization using reactive elements such as …
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Electronic simulation of an associative neuron
… important features which determine the input and output characteristics and the responses of a neuron. Included are both of the major inhibition characteristics: presynaptic inhibition (depolarization), and postsynaptic inhibition (hyperpolarization). The simulation presented uses a single 12 volt …
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