Integrinių analoginių filtrų belaidžio ryšio sistemoms kūrimas

Disertacijoje nagrinėjami konfigūruojami analoginiai filtrai su savaiminio derinimo grandynais, jų projektavimo ir įgyvendinimo būdai, kurie pritaikomi integrinių grandynų gamybos technologijoms. Iškeliama ir įrodoma hipotezė, teigianti, kad savaiminio derinimo grandynų taikymas įgalina gauti integrinių analoginių aktyviųjų rezistorių kondensatorių (RC) filtrų parametrus reikalau¬jamu tikslumu. Darbo tikslas – sukurti savaiminio derinimo grandynus, skirtus konfigūruojamų integrinių analoginių aktyviųjų RC filtrų parametrų gavybai reikalaujamu tikslumu. Darbe išspręsti uždaviniai: ištirtos integrinių analoginių aktyviųjų RC filtrų struktūros ir sukurti jų derinimo grandynų modeliai, pasiūlytas integrinių analoginių aktyviųjų RC filtrų derinimo matricų projektavimo būdas, sukurtas ir ištirtas konfigūruojamas integrinis analoginis aktyvusis RC filtras su diskrečiu ir tolydžiu savaiminio derinimo grandynais. Disertaciją sudaro įvadas, trys skyriai, bendrosios išvados, naudotos literatū¬ros ir autoriaus publikacijų disertacijos tema sąrašai ir penki priedai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas bei uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai, disertacijos struktūra. Pirmame skyriuje apžvelgiamos integrinių analoginių filtrų struktūros, pagrindiniai parametrai bei įvardijamos parametrų verčių svyravimo priežastys, analizuojamos savaiminio derinimosi grandynų struktūros ir jų veikimo principai. Skyriaus pabaigoje, remiantis atlikta analize ir sudarytomis išvadomis suformuluojami disertacijos uždaviniai. Antrajame skyriuje sudaroma konfigūruojamo integrinio analoginio filtro struktūra, skirta programine įranga valdomam radijui, sudaromi diskretaus ir tolydaus derinimo matricų modeliai, juos sudarančių elementų verčių parinkimo algoritmai, atliekami modelių ir algoritmų kompiuteriniai skaičiavimai. Trečiajame skyriuje, pasinaudojus sukurtais modeliais ir algoritmais, suprojektuojamas filtras su diskrečiu ir tolydžių savaiminio derinimo grandynais, naudojant eksperimentinius ir kompiuterinius skaičiavimo metodus atliekamas suprojektuotų diskrečiai ir tolydžiai valdomų integrinių analoginių RC filtrų parametrų bei jų savaiminio derinimo grandynų tyrimas. Disertacijos tema yra atspausdinti 7 moksliniai straipsniai: du – mokslo žurnaluose, įtrauktuose į Thomson Reuters Web of Science duomenų bazę, vienas – tarptautinių konferencijų medžiagoje, įtrauktoje į Thomson Reuters Proceedings duomenų bazę, keturi – mokslo žurnaluose, referuojamose kitose tarptautinėse duomenų bazėse. Disertacijoje atliktų tyrimų rezultatai buvo pristatyti septyniose mokslinėse konferencijose Lietuvoje ir užsienyje

Development of adaptive control system for technological facility of primary oil refining

As it is known, primary oil processing facilities are designed for the production of light-colored oil products and various oil fractions that meet modern requirements with their quality. The main equipment of these technological facilities are rectification columns operating under atmospheric and vacuum conditions, which perform the decomposition of crude oil and fuel oil into various product fractions. Generally, the quality indicators of product fractions produced in these columns are provided by stabilizing the temperature modes at certain points (plates) of these or rectification columns by regulating the irrigation consumption supplied to those plates. It should be noted that currently, in accordance with the requirements of the time, the design and development of new control systems that can adequately respond to more dynamic and variable external and internal stimulating influences for complex oil refining technological facilities is one of the main problems facing the automatic control theory. The paper is dedicated to the issue of developing a new automated control system that can provide the required accuracy in terms of quality management. As an adaptive control system, the purpose of such systems is to compensate in time for disturbance influences in the technological devices and to ensure the production of oil products with stable quality indicators, regardless of these influences. The purpose of study is to develop a control system that can meet the given requirements and ensure the produced products with relatively stable quality indicators, regardless of the controlled and uncontrolled exciting effects affecting the oil refinery technological complex. The principle of operation of this system is based not only on the compensation of disturbance influences but also on the calculation of new operation strategies depending on these effects. The development of new automated control system that is able to provide the necessary accuracy of quality control in the lack of information is relevan

ПАРАМЕТРИЧЕСКАЯ ОПТИМИЗАЦИЯ ДВУХКАНАЛЬНОГО АВТОКОМПЕНСАТОРА МЕШАЮЩИХ ИЗЛУЧЕНИЙ

The task of optimizing of the compensators of interfering radiations in radars with fast linear scanning is relevant. The main problem of autocompensators with a gradient self-tuning method is the large dynamic errors in the formation of weight coefficients. To reduce the impact of dynamic errors on compensation efficiency, the bandwidth extension of closed self-tuning circuits is used. However, in this case, the contribution of fluctuation errors to the total errors increases. There are optimal values of autocompensator parameters, at which the total errors are minimal. The article obtained expressions for the optimal parameters of a dualchannel auto-compensator for interfering radiations with a gradient self-tuning method when suppressing the signals of two radiation sources. For simplicity, the case of self-tuning chains with the first order of astatism is considered, and the side lobes of the main radiation pattern are described by harmonic approximation. The obtained results are confirmed by the simulation modeling of a two-channel auto-compensator.Задача оптимизации автокомпенсаторов мешающих излучений в РЛС с быстрым линейным сканированием является актуальной. Основной проблемой автокомпенсаторов с градиентным способом самонастройки являются большие динамические ошибки формирования весовых коэффициентов. Для снижения влияния динамических ошибок на эффективность компенсации используют расширение полос пропускания замкнутых контуров самонастройки. Однако в этом случае увеличивается вклад флуктуационных ошибок в суммарные ошибки. Существуют оптимальные значения параметров автокомпенсатора, при которых суммарные ошибки минимальны. В статье получены выражения для оптимальных параметров двухканального автокомпенсатора мешающих излучений с градиентным способом самонастройки при подавлении сигналов двух источников излучения. Для простоты рассматривается случай цепей самонастройки с первым порядком астатизма, а боковые лепестки основной диаграммы направленности описываются гармонической аппроксимацией. Полученные результаты подтверждаются имитационным моделированием двухканального автокомпенсатора

High frequency and high dynamic range continuous time filters

Many modern communication systems use orthogonal frequency division multiplexing (OFDM) and discrete multi-tone (DMT) as modulation schemes where high data rates are transmitted over a wide frequency band in multiple orthogonal subcarriers. Due to the many advantages, such as flexibility, good noise immunity and the ability to be optimized for medium conditions, the use of DMT and OFDM can be found in digital video broadcasting, local area wireless network (IEEE 802.11a), asymmetric digital subscriber line (ADSL), very high bit rate DSL (VDSL) and power line communications (PLC). However, a major challenge is the design of the analog frontend; for these systems a large dynamic range is required due to the significant peak to average ratio of the resulting signals. In receivers, very demanding high-performance analog filters are typically used to block interferers and provide anti-aliasing before the subsequent analog to digital conversion stage. For frequencies higher than 10MHz, Gm-C filter implementations are generally preferred due to the more efficient operation of wide-band operational transconductance amplifiers (OTA). Nevertheless, the inherent low-linearity of open-loop operated OTA limits the dynamic range. In this dissertation, three different proposed OTA linearity enhancement techniques for the design of high frequency and high dynamic range are presented. The techniques are applied to two filter implementations: a 20MHz second order tunable filter and a 30MHz fifth order elliptical low-pass filter. Simulation and experimental results show a spurious free dynamic range (SFDR) of 65dB with a power consumption of 85mW. In a figure of merit where SFDR is normalized to the power consumption, this filter is 6dB above the trend-line of recently reported continuous time filters

Design methodology for reliable and energy efficient self-tuned on-chip voltage regulators

The energy-efficiency needs in computing systems, ranging from high performance processors to low-power devices is steadily on the rise, resulting in increasing popularity of on-chip voltage regulators (VR). The high-frequency and high bandwidth on-chip voltage regulators such as Inductive voltage regulators (IVR) and Digital Low Dropout regulators (DLDO) significantly enhance the energy-efficiency of a SoC by reducing supply noise and enabling faster voltage transitions. However, IVRs and DLDOs need to cope with the higher variability that exists in the deep nanometer digital nodes since they are fabricated on the same die as the digital core affecting performance of both the VR and digital core. Moreover, in most modern SoCs where multiple power domains are preferred, each VR needs to be designed and optimized for a target load demand which significantly increases the design time and time to market for VR assisted SoCs. This thesis investigates a performance-based auto-tuning algorithm utilizing performance of digital core to tune VRs against variations and improve performance of both VR and the core. We further propose a fully synthesizable VR architecture and an auto-generation tool flow that can be used to design and optimize a VR for given target specifications and auto-generate a GDS layout. This would reduce the design time drastically. And finally, a flexible precision IVR architecture is also explored to further improve transient performance and tolerance to process variations. The proposed IVR and DLDO designs with an AES core and auto-tuning circuits are prototyped in two testchips in 130nm CMOS process and one test chip in 65nm CMOS process. The measurements demonstrate improved performance of IVR and AES core due to performance-based auto-tuning. Moreover, the synthesizable architectures of IVR and DLDO implemented using auto-generation tool flow showed competitive performance with state of art full custom designs with orders of magnitude reduction in design time. Additional improvement in transient performance of IVR is also observed due to the flexible precision feedback loop design.Ph.D

CEAS/AIAA/ICASE/NASA Langley International Forum on Aeroelasticity and Structural Dynamics 1999

The proceedings of a workshop sponsored by the Confederation of European Aerospace Societies (CEAS), the American Institute of Aeronautics and Astronautics (AIAA), the National Aeronautics and Space Administration (NASA), Washington, D.C., and the Institute for Computer Applications in Science and Engineering (ICASE), Hampton, Virginia, and held in Williamsburg, Virginia June 22-25, 1999 represent a collection of the latest advances in aeroelasticity and structural dynamics from the world community. Research in the areas of unsteady aerodynamics and aeroelasticity, structural modeling and optimization, active control and adaptive structures, landing dynamics, certification and qualification, and validation testing are highlighted in the collection of papers. The wide range of results will lead to advances in the prediction and control of the structural response of aircraft and spacecraft