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Design of large time constant switched-capacitor filters for biomedical applicationsTumati, Sanjay 17 February 2005 (has links)
This thesis investigates the various techniques to achieve large time constants and the ultimate limitations therein. A novel circuit technique for the realization of large time constants for high pass corners in switched-capacitor filters is also proposed and compared with existing techniques. The switched-capacitor technique is insensitive to parasitic capacitances and is area efficient and it requires only two clock phases. The circuit is used to build a typical switched-capacitor front end with a gain of 10. The low pass corner is fixed at 200 Hz. The high pass corner is varied from 0.159Hz to 4 Hz and various performance parameters, such as power consumption, silicon area etc., are compared with conventional techniques and the advantages and disadvantages of each technique are demonstrated. The front-ends are fully differential and are chopper stabilized to protect against DC offsets and 1/f noise. The front-end is implemented in AMI0.6um technology with a supply voltage of 1.6V and all transistors operate in weak inversion with currents in the range of tens of nano-amperes.
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Design of large time constant switched-capacitor filters for biomedical applicationsTumati, Sanjay 17 February 2005 (has links)
This thesis investigates the various techniques to achieve large time constants and the ultimate limitations therein. A novel circuit technique for the realization of large time constants for high pass corners in switched-capacitor filters is also proposed and compared with existing techniques. The switched-capacitor technique is insensitive to parasitic capacitances and is area efficient and it requires only two clock phases. The circuit is used to build a typical switched-capacitor front end with a gain of 10. The low pass corner is fixed at 200 Hz. The high pass corner is varied from 0.159Hz to 4 Hz and various performance parameters, such as power consumption, silicon area etc., are compared with conventional techniques and the advantages and disadvantages of each technique are demonstrated. The front-ends are fully differential and are chopper stabilized to protect against DC offsets and 1/f noise. The front-end is implemented in AMI0.6um technology with a supply voltage of 1.6V and all transistors operate in weak inversion with currents in the range of tens of nano-amperes.
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An integrated analog controller for signal based A/D conversionChen, Hsin-Yu 11 August 2008 (has links)
Abstract:
This thesis is concerned with the acquisition of body signals using a sampling system. A typical
application is the recording of the electrocardiogram (ECG). It is proposed to sample the input
signal at different rates, depending on the momentary signal content. If the input signal has large
voltage variation, it is sampled at a high rate. During periods of small variation, the signal is
sampled at a lower frequency to save both memory and power. An analog controller to control the
clock rate is proposed and implemented. The analog controller decides the sample frequency (high
rate or low rate) depending on the input signal. The analysis of the proposed system is presented in
this thesis. Furthermore, a working prototype is implemented using discrete components on a PCB.
The measured results show a significant reduction in the average sample frequency and data rate of
50% and 35%, respectively. Finally, the critical analog circuit blocks of the system suitable for
integration on chip are proposed and implemented in a 0.35£gm CMOS process. Measured results
are reported to confirm the functionality of the blocks.
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Flux Estimation, Parameter Adaptation And Speed Sensorless Control For Vector Controlled Induction Motor DriveBhattacharya, Tanmoy 01 1900 (has links) (PDF)
No description available.
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Pulsed Power and Load-Pull Measurements for Microwave TransistorsSomasundaram Meena, Sivalingam 29 October 2009 (has links)
A novel method is shown for fitting and/or validating electro-thermal models using pulsed I(V) measurements and pulsed I(V) simulations demonstrated using modifications of an available non-linear model for an LDMOS (Laterally Diffused Metal Oxide Semiconductor) device. After extracting the thermal time constant, good agreement is achieved between measured and simulated pulsed I(V) results under a wide range of different pulse conditions including DC, very short (<0.1%) duty cycles, and varied pulse widths between these extremes. A pulsed RF load-pull test bench was also assembled and demonstrated for a VDMOS (Vertically Diffused Metal Oxide Semiconductor) and an LDMOS power transistor. The basic technique should also be useful for GaAs and GaN transistors with suitable consideration for the complexity added by trapping mechanisms present in those types of transistors.
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Effectiveness of energy wheels from transient measurementsAbe, Oyetope Omobayode 22 June 2005
<p>Certification of energy wheel effectiveness by a selected international laboratory for many types and sizes of wheel produced by each manufacturer has proven to be very expensive and has been prone to large uncertainties. This research uses a new, low-cost, transient method to predict the effectiveness using only data obtained from transient measurements.</p><p>In this thesis, an analytical model is presented for predicting the effectiveness of rotating energy wheels using only the characteristics measured on the same non-rotating wheels exposed to a step change in temperature and humidity. A relationship between the step response and the periodic response of an energy wheel is developed using first order linear system design theory. This allows the effectiveness of an energy wheel to be predicted when the characteristics of a step response are known. The effectiveness correlations and uncertainty bounds for sensible and latent effectiveness of energy wheels determined from transient measurements are thus presented.</p><p>The experimental transient testing method and experimental verification of the effectiveness model for several different wheels are also presented in this thesis. The results obtained from the new effectiveness model are shown to agree, within uncertainty bounds, with the results obtained from the standard steady state experimental testing method and numerical simulations.</p>
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Effectiveness of energy wheels from transient measurementsAbe, Oyetope Omobayode 22 June 2005 (has links)
<p>Certification of energy wheel effectiveness by a selected international laboratory for many types and sizes of wheel produced by each manufacturer has proven to be very expensive and has been prone to large uncertainties. This research uses a new, low-cost, transient method to predict the effectiveness using only data obtained from transient measurements.</p><p>In this thesis, an analytical model is presented for predicting the effectiveness of rotating energy wheels using only the characteristics measured on the same non-rotating wheels exposed to a step change in temperature and humidity. A relationship between the step response and the periodic response of an energy wheel is developed using first order linear system design theory. This allows the effectiveness of an energy wheel to be predicted when the characteristics of a step response are known. The effectiveness correlations and uncertainty bounds for sensible and latent effectiveness of energy wheels determined from transient measurements are thus presented.</p><p>The experimental transient testing method and experimental verification of the effectiveness model for several different wheels are also presented in this thesis. The results obtained from the new effectiveness model are shown to agree, within uncertainty bounds, with the results obtained from the standard steady state experimental testing method and numerical simulations.</p>
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We could predict good responders to vagus nerve stimulation: a surrogate marker by slow cortical potential shift / 脳波の緩電位変化は迷走神経刺激療法の治療効果の代替マーカーとなるBorgil, Bayasgalan 24 November 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20755号 / 医博第4285号 / 新制||医||1024(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 伊佐 正, 教授 宮本 享, 教授 井上 治久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Recursive Methods in Urn Models and First-Passage PercolationRenlund, Henrik January 2011 (has links)
This PhD thesis consists of a summary and four papers which deal with stochastic approximation algorithms and first-passage percolation. Paper I deals with the a.s. limiting properties of bounded stochastic approximation algorithms in relation to the equilibrium points of the drift function. Applications are given to some generalized Pólya urn processes. Paper II continues the work of Paper I and investigates under what circumstances one gets asymptotic normality from a properly scaled algorithm. The algorithms are shown to converge in some other circumstances, although the limiting distribution is not identified. Paper III deals with the asymptotic speed of first-passage percolation on a graph called the ladder when the times associated to the edges are independent, exponentially distributed with the same intensity. Paper IV generalizes the work of Paper III in allowing more edges in the graph as well as not having all intensities equal.
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Charakterizace materiálů pro perovskitové solární články transientními metodami / Characterization of perovskite solar cell materials by transient techniquesNakládal, Martin January 2020 (has links)
This thesis deals with the study of the lifetime of charge carriers in perovskite single crystals. The principle of perovskite solar cells is formulated, their main structures are characterized and the history of the development of perovskite solar cells is summarized, especially in terms of efficiency. The properties of perovskite single crystals with perovskite solar cells are compared. For measurement purposes, transient methods, impedance spectroscopy, load characteristics and the dependence of sensitivity and photocurrent on the wavelength of incident radiation are described. The practical part deals with the method of measuring and evaluating the lifetime of charge carriers in the investigated perovskite single crystals.
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