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Добірка наукової літератури з теми "Amplitude-frequency characteristic"

Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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Статті в журналах з теми "Amplitude-frequency characteristic"

Klaerner, Matthias, Mario Wuehrl, Lothar Kroll, and Steffen Marburg. "Characteristic amplitude-frequency functions of the radiated sound power." Journal of the Acoustical Society of America 141, no. 5 (May 2017): 4034. http://dx.doi.org/10.1121/1.4989301.

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Liu, Hai Jiang, and Hong Yan Wang. "Development of the Amplitude-Frequency Characteristic Tester Based on SCM Control." Advanced Materials Research 706-708 (June 2013): 776–80. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.776.

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In this paper, the development of the amplitude-frequency characteristic tester based on SCM control has been introduced. The digital frequency synthesizer has been adopted to generate the automatic sweep frequency sine signals so as to provide the reliable sources for the frequency characteristic tester. The amplitude and the frequency characteristics of the active network and the passive network can be obtained through changing the output signals of circuit measuring network by digital analogy as well as the operation program of the microcontroller under the input signals with different frequencies. In this paper, the working principles of tester, the software and hardware design for the frequency synthesizer signals, the hardware and software design of the data collection channels and the applications of LCD technology have been specially discussed.

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Yu, Liang Jun, Li Hua Sun, and Cui Cui Huang. "Design of Comprehensive Test Instrument Based on FPGA and Cortex-M0." Applied Mechanics and Materials 312 (February 2013): 583–87. http://dx.doi.org/10.4028/www.scientific.net/amm.312.583.

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The design consists of three modules: the voltage amplitude measurement module, the level oscillator module and the amplitude-frequency characteristic test module. The voltage amplitude measurement module uses AD817 to consist three-stage amplifier. The magnification of each level can be adjusted for 1 times/10 times. At the same time, the author uses the Cortex-M0 for controlling the relay switch to achieve automatic range conversion. The principle of DDS is adopted in the level oscillator module. FPGA is used for realizing the phase accumulator, the phase modulator, the sine ROM look-up table. Digital signal is finally outputted by high-speed analog-to-digital conversion chip DAC900. Then, by controlling the 6-channel relay switch to make the magnification in the amplifying circuit,which can be adjusted step-by-step from-30dB to 20dB. Through outputting sine wave whose amplitude is fixed, but frequency is variable to the network under test, amplitude-frequency characteristic test module measures the relation betthe authoren the amplitude change of the output signal and the signal frequency to obtain the amplitude-frequency characteristics of the network under test..

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Паровик, Р. И. "Анализ добротности вынужденных колебаний дробного линейного осциллятора". Журнал технической физики 90, № 7 (2020): 1059. http://dx.doi.org/10.21883/jtf.2020.07.49436.233-19.

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Using the harmonic balance method, analytical formulas are obtained for calculating the amplitude-frequency and phase-frequency characteristics, as well as the quality factor of the forced oscillations of a linear fractional oscillator. It was established that the characteristics under study depend on the dissipative properties of the medium - memory effects, which are described by derivatives of fractional orders. It is shown that fractional orders affect the attenuation of the oscillatory process and are associated with its quality factor. The calculated curves of the characteristics of the forced oscillations of a linear linear fractional oscillator showed that fractional orders can be considered as control parameters of the oscillatory process in a dissipative medium. Key words: quality factor, amplitude-frequency characteristic, phase-frequency characteristic, fractional derivatives, memory.

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Abramov, Y., V. Kryvtsova, and A. Mikhailyuk. "JUSTIFICATION OF THE METHOD OF DETERMINATION OF THE CONSTANT TIME OF THE GAS GENERATOR OF THE SYSTEM OF STORAGE AND SUPPLY OF HYDROGEN." Municipal economy of cities 3, no. 163 (June 29, 2021): 216–20. http://dx.doi.org/10.33042/2522-1809-2021-3-163-216-220.

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The method of determining the dynamic parameter - the time constant of the gas generator of the storage and supply of hydrogen on the basis of the hydro-reactive composition is substantiated. The method is based on the use of the amplitude-frequency characteristics of the gas generator of the storage and supply system of hydrogen. The method involves the implementation of three stages. At the first stage, the mathematical dependence of the gas generator time constant on its static parameter and amplitude-frequency characteristic at a fixed frequency is obtained. In the second stage, the choice of this fixed frequency is justified. This dependence includes the value of the amplitude-frequency characteristic of the gas generator of the storage and supply of hydrogen at a fixed frequency, the static parameter of such a gas generator – its transmission coefficient, and the value of the fixed frequency. In the second stage, the choice of this fixed frequency is justified. This choice is made provided that the minimum error in determining the time constant of the gas generator. To determine the static parameter of the gas generator and the value of its amplitude-frequency characteristic at a fixed frequency, an array of data is used, which is formed by measuring the values of the transient function of the gas generator through equal moments of time. These time intervals are chosen according to the Kotelnikov-Nyquist-Shannon theorem. The amplitude-frequency characteristic of the gas generator of the hydrogen storage and supply system is determined numerically. According to the research results, an iterative procedure for determining the time constant of the gas generator of the hydrogen storage and supply system is given. Recommendations for using this procedure are given. The choice of the time constant of the gas generator of the hydrogen storage and supply system is made using the tolerance criterion.

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Xu, Lu, Hongsheng Li, Jia Liu, Yunfang Ni, and Libin Huang. "Research on Nonlinear Dynamics of Drive Mode inZ-Axis Silicon Microgyroscope." Journal of Sensors 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/801618.

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A novel drive method is proposed to increase the vibration amplitude of drive mode of silicon vibratory gyroscopes based on the nonlinear dynamics research made in this paper. A nonlinear dynamic equation, considering the nonlinear mechanical-elastic and electrostatic force, was firstly deduced according to the simplified structure schematic of drive mode. Then, experiments were made to characterize the nonlinear amplitude-frequency response characteristic as well as its dependence on drive voltage. Besides, by solving the nondimensional nonlinear dynamics using Matlab and Simulink, the influence of initial status of drive mode, that is, the displacement and the velocity, on the stable vibration amplitude was presented. The amplitude-frequency characteristic was also analyzed by simulation. The result of simulation shows good agreement with that of experiments. When nonlinearity is present in the amplitude-frequency characteristic, there is a wide flat region with larger amplitude than the peak amplitude obtained in the linear characteristic. Finally, a novel drive method was presented to excite the nonlinear vibration of large amplitude in the downwards-sweeping characteristic curve. It is numerically proved that this merit can be utilized to enlarge the drive mode’s vibration amplitude so as to enhance silicon gyroscopes’ performance.

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Parovik, Roman. "Frequency characteristics of the fractional oscillator Van der Pol." E3S Web of Conferences 127 (2019): 02010. http://dx.doi.org/10.1051/e3sconf/201912702010.

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Into this paper, the amplitude-frequency and phase-frequency characteristics of the Van der Polar fractional oscillator are studied in order to establish their relationship with the orders of fractional derivatives included in the model equation. Using the harmonic balance method, analytical formulas were obtained for the amplitude-frequency, phase-frequency characteristics, as well as the quality factor – the energy characteristic of the oscillatory system. It was shown that the quality factor depends on the orders of fractional derivatives, and change in their values can lead to both an increase and a decrease in the quality factor.

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Li, Li Ping. "Experiment Analysis about Mechanical Properties of Rubber Bushing for Suspension Telescopic Shock Absorber." Applied Mechanics and Materials 670-671 (October 2014): 1008–11. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.1008.

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The experiments of static and dynamic characteristics of rubber bushing for rear suspension telescopic shock absorber were carried out at four directions such as axial, radial, torsion and yaw, by MTS831 and SAGINOMIYA test system. The tests prove that: rubber bushing has great damping, and rubber bushing has obvious nonlinear characteristic; the dynamic stiffness under low frequency and large amplitude excitation is smaller, while the dynamic stiffness under high frequency and small amplitude excitation is greater; at the same amplitude, the dynamic stiffness increases with the increasing excitation frequency. The test results can provide support for the optimization design of rubber bushing.

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Xu, Jinli, Jiwei Zhu, and Feifan Xia. "Modeling and Analysis of Amplitude-Frequency Characteristics of Torsional Vibration for Automotive Powertrain." Shock and Vibration 2020 (August 29, 2020): 1–17. http://dx.doi.org/10.1155/2020/6403413.

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In the present paper, the amplitude-frequency characteristics of torsional vibration are discussed theoretically and experimentally for automotive powertrain. A bending-torsional-lateral-rocking coupled dynamic model with time-dependent mesh stiffness, backlash, transmission error etc. is proposed by the lumped-mass method to analysis the amplitude-frequency characteristic of torsional vibration for practical purposes, and equations of motive are derived. The Runge–Kutta method is employed to conduct a sweep frequency response analysis numerically. Furthermore, a torsional experiment is performed and validates the feasibility of the theoretical model. As a result, some torsional characteristics of automotive powertrain are obtained. The first three-order nature torsional frequencies are predicted. Torsional behaviors only affect the vibration characteristics of a complete vehicle at low-speed condition and will be reinforced expectedly while increasing torque fluctuation. Gear mesh excitations have little effects on torsional responses for such components located before mesh point but a lot for ones behind it. In particular, it is noted that the torsional system has a stiffness-softening characteristic with respect to torque fluctuation.

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Ma, Liang, Jun Wang, and Guichang Zhang. "The Dynamic Characteristic of a Faulted Rotor System with Multi-Objective Optimization Designed SFD." Applied Sciences 9, no. 17 (September 3, 2019): 3628. http://dx.doi.org/10.3390/app9173628.

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As an important part of the turbomachinery, the rotor–bearing system has been upgraded to provide a high rotating speed in order to meet the demand of high power production. With increasing demand for stability, the squeeze film damper (SFD) has been widely used in industrial machinery because it can reduce the vibration amplitude and suppress the external force. Usually, it shows inadaptability under the different working conditions where the SFD parameters didn’t change appropriately. Therefore, the reasonable choice of operational parameters of SFD is the key solution that can provide viscous damping effectively and restrain the nonlinear vibration generated by faults. In this paper, the mathematical model of a rotor-ball bearing-SFD system considering the misalignment fault and misalignment-rubbing coupling fault is built first. Then the dynamic characteristics under typical working conditions (ω = 1000 rad/s) of the faulted rotor are discussed. The vibration attenuation effects of the SFD parameters selected by using the multi-objective optimization method on the dynamic responses are analyzed. The results show that when the rotor system operates under different states, the value and the sensitivity of optimization parameters are altered. With no fault, the amplitude of fundamental frequency decrease 23%. With the misalignment fault, the amplitude of the fundamental frequency decreases by 43.4%, the amplitude of 2× fundamental frequency decreases by 27.5%, and the amplitude of 3× fundamental frequency decreases by 66.7%. With the misalignment-rubbing coupling fault, the amplitude of fundamental frequency reduces by 7.4%, the amplitude of 2× fundamental frequency drops by 51.5%, and the amplitude of 3× fundamental frequency drops by 16.8%. Overall, the feasibility of the optimization method of the variable-structured SFD operational parameters for the faulted rotor system is verified. These parametric analyses are very helpful in the development of a high-speed rotor system and provide a theoretical reference for the vibration control and optimal design of rotating machinery.

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Більше джерел

Дисертації з теми "Amplitude-frequency characteristic"

Černý, Ondřej. "Stanovení druhé viskozity kapaliny z měřených tlakových pulsací." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229379.

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Diploma thesis deals with problem of assessment of the second viscosity and acoustic velocity coefficients by the different liquid´s flow in pipe from measured pressure pulstation created by diaphragm pulsator. For the solution is used a transfer matrix model and for the data evaluation a genetic algorithm in „Facharp.exe“ program. Modal analysis in problematic part of the measured stand is realized to find a wave shapes and natural frequency of a pipe. The results are for the reason of clearness processed into „MS Excel“ program and fetched to the charts which shows depedence of a second viscosity and acoustic velocity coefficients on a various flow as the final result.

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Guzej, Michal. "Rotující odtržení v prostoru odstředivého kompresoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230025.

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This thesis deals with a procedure for determining the complete processing of aerodynamic flow instabilities (rotating stall and surge) in a centrifugal compressor. At small flows the performance of a compressor system is limited by the surge line, which is caused by flow instabilities. Numerical solution is obtained using the method of transfer matrix. This system is simulated through several models with local resistances that represent the dissipation of pressure energy. Pulses are excitated in these models by the pressure jump placed before the centrifugal compressor. From the frequency-amplitude characteristics for the selected range of frequencies and flow the impedance characteristic of the compressor system is determined. We are looking for problematic frequencies in this characteristic that cause flow instabilities in the compressor system.

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Slavíček, Ondřej. "Dynamické charakteristiky běžně používaných snímačů tlaku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254445.

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This thesis deals with the dynamic properties of electric pressure transducers. These are properties that are reflected in the measurement of rapid, time-dependent processes. They could be described in two ways. Either by using amplitude and phase frequency response characteristics, or just one particular value. Natural frequency, cutoff frequency or time constant. These parameters indicate the extreme values for the use of measuring devices in the measurement of time-dependent processes. In this work will be described procedures for determining these parameters.

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Vig, Jyotika. "ISM Band Indoor Wireless Channel Amplitude Characteristics: Path Loss and Gain vs. Distance and Frequency." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1091111060.

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Sucic, Victor. "Parameters Selection for Optimising Time-Frequency Distributions and Measurements of Time-Frequency Characteristics of Nonstationary Signals." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15834/.

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The quadratic class of time-frequency distributions (TFDs) forms a set of tools which allow to effectively extract important information from a nonstationary signal. To determine which TFD best represents the given signal, it is a common practice to visually compare different TFDs' time-frequency plots, and select as best the TFD with the most appealing plot. This visual comparison is not only subjective, but also difficult and unreliable especially when signal components are closely-spaced in the time-frequency plane. To objectively compare TFDs, a quantitative performance measure should be used. Several measures of concentration/complexity have been proposed in the literature. However, those measures by being derived with certain theoretical assumptions about TFDs are generally not suitable for the TFD selection problem encountered in practical applications. The non-existence of practically-valuable measures for TFDs' resolution comparison, and hence the non-existence of methodologies for the signal optimal TFD selection, has significantly limited the use of time-frequency tools in practice. In this thesis, by extending and complementing the concept of spectral resolution to the case of nonstationary signals, and by redefining the set of TFDs' properties desirable for practical applications, we define an objective measure to quantify the quality of TFDs. This local measure of TFDs' resolution performance combines all important signal time-varying parameters, along with TFDs' characteristics that influence their resolution. Methodologies for automatically selecting a TFD which best suits a given signal, including real-life signals, are also developed. The optimisation of the resolution performances of TFDs, by modifying their kernel filter parameters to enhance the TFDs' resolution capabilities, is an important prerequisite in satisfying any additional application-specific requirements by the TFDs. The resolution performance measure and the accompanying TFDs' comparison criteria allow to improve procedures for designing high-resolution quadratic TFDs for practical time-frequency analysis. The separable kernel TFDs, designed in this way, are shown to best resolve closely-spaced components for various classes of synthetic and real-life signals that we have analysed.

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Lott, Gus K. Jr. "High Frequency (HF) radio signal amplitude characteristics, HF receiver site performance criteria, and expanding the dynamic range of HF digital new energy receivers by strong signal elimination [electronic resource]." Thesis, Monterey, California: Naval Postgraduate School, 1990. http://hdl.handle.net/10945/34806.

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Approved for public release; distribution unlimited.
The dissertation discusses High Frequency (HF) radio sources. It consolidates data from all available, published HF spectrum surveys. The author conducted a new HF survey using detection of new energy events. The first cumulative probability distribution function for the amplitude of detected non-broadcast HF signals is developed, and the distribution is log-normal. HF receiver site performance quantification is possible using the HF signal distributions. Site performance degradation results from noise, interference, and signal path attenuation. Noise examples are presented in a 3-D format of time, frequency, and amplitude. Graphs are presented that allow estimation of the percentage of HF non-broadcast signals lost as a function of noise and interference levels. Limitations of HF search receivers using analog-to-digital converters as the receiver front-end are discussed. Derived bounds on AD converter performance show that today's digital technology does not provide enough dynamic range, sensitivity, or sampling rate. Alternative dynamic range extension methods are examined. A new method of dynamic range extension by removing the strongest signals present is presented. Greater receiver sensitivity results from changing the HF signal environment seen by the AD converter. The new method uses a phase-tracking network and signal reconstruction techniques.

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Дубицька, Марія Сергіївна, Мария Сергеевна Дубицкая та M. S. Dubyts’ka. "Вдосконалення способу прогнозу диз’юнктивних порушень методом акустичної геолокації при відпрацюванні пологозалягаючих вугільних пластів". Thesis, Видавництво НГУ, 2014. http://ir.nmu.org.ua/handle/123456789/3692.

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Анотація:

У дисертації вирішене актуальне науково-технічне завдання підвищення ефективності прогнозу мілкоамплітудних геологічних порушень вугільних пластів методом неруйнівного контролю до 95%. Запропонована і обґрунтована математична модель розповсюдження акустичного хвильового пакету в дисперсійному породному середовищі, заснована на інформаційній амплітудно-фазовій модуляції несучих частот зондуючого сигналу. Розроблено ефективний спосіб прогнозу прихованих диз'юнктивів у вугільних пластах методом неруйнівного контролю. У його основу покладено аналіз особливостей прояву розривних геологічних порушень у функціях модуляційних параметрів сигналу, який отримано в результаті акустичного зондування вуглепородного масиву. Закономірності, отримані в результаті досліджень використані для розробки рекомендацій щодо тектонічної будови вугільних пластів для шахт «Дніпровська», «Краснолиманська» та «Степова».
В диссертации решена актуальная научно-техническая задача повышения эффективности прогноза малоамплитудных геологических нарушений угольных пластов методом неразрушающего контроля до 95%. Организованы и проведены комплексные шахтные, лабораторные и аналитические исследования распространения акустических колебаний в сложноструктурном породном массиве с геологическими нарушениями при использовании различных способов генерации зондирующего акустического сигнала. Впервые доказан факт информационной амплитудно-фазовой модуляции низкочастотных огибающих спектральной плотности мощности несущих частот зондирующего сигнала, прошедшего через исследуемый породный массив. Предложена и обоснована математическая модель распространения акустического волнового пакета в диспергирующей породной среде, отличающаяся от известных тем, что основана она на информационной амплитудно-фазовой модуляции несущих частот зондирующего сигнала. Предложена методика обработки сигнала волнового пакета зондирующего сигнала, прошедшего сквозь структурно-неоднородный породный массив, отличающаяся от известных тем, что в ее основу заложена фазовая демодуляция функции спектральной плотности мощности с применением метода низкочастотного эквивалента. Методика позволяет определить геометрические параметры неоднородностей при прохождении выработок в зонах геологических нарушений. Установлено, что исследование низкочастотной огибающей спектральной плотности мощности несущих частот и последующая ее фазовая демодуляция в среде Matlab позволяет получить фазовые характеристики огибающей, которые несут в себе информационную составляющую, отвечающую за структуру угольного пласта. Доказано, что в случае наличия нарушения график фазовой характеристики имеет один глобальный экстремум, который существенно отличается от остальных – локальных – своей первой производной. Причем, при фазовой демодуляции максимальная амплитуда несущей частоты иногда бывает менее информативна, чем боковые, поэтому в программе оценки нижних частот расчет функции полной фазы низкочастотных спектральных составляющих, осуществляется по четырем несущим с максимальной амплитудой, а среди них выбирается одна – с наиболее резким изменением сигнала. На основе их анализа сделан вывод о том, что на изгибе функции отражается излом характеристики. Доказано, что точка глобального экстремума фазовой характеристики низкочастотной огибающей спектральной плотности мощности несущих частот, вычисляемая методом низкочастотного эквивалента, определяет местонахождение разрывного геологического нарушения в угольном пласте с надежностью не менее 0.95, что позволяет существенно повысить надежность прогноза геоакустическим методом. Описанная точка экстремума возникает в определенное время распространения искусственного сигнала. Имея данные о местонахождении источника сигнала в момент времени его прохождения сквозь массив, местонахождении приемника и скорость распространения акустической волны в волноводе можно определить координаты соответствующей точки разрывного нарушения. Основываясь на анализе данного экстремума установлено, что координаты разрывного нарушения на прямой от источника искусственно генерируемого сигнала до приемника в плоскости волновода определяются произведением средней скорости распространения акустического колебания в угольном пласте и временем, соответствующем возникновению глобального экстремума фазовой характеристики низкочастотной огибающей спектральной плотности мощности несущих частот, что позволяет определить геометрические параметры разрывного нарушения в угольном пласте. Разработан эффективный способ прогноза скрытых дизьюнктивов в угольных пластах методом неразрушающего контроля. В его основу положен анализ особенностей проявления разрывных геологических нарушений в функциях модуляционных параметров сигнала, который получен в результате акустического зондирования углепородного массива. Закономерности, полученные в результате исследований использованы для разработки рекомендаций относительно тектонического строения угольных пластов для шахт «Краснолиманская» ГП «УК «Краснолиманская», «Днепровская» и «Степная» ПАО «ДТЭК Павлоградуголль».
In the thesis, the actual scientific and technical problem of raising efficiency of low-amplitude geological disturbances forecast in coal layers by the method of nondestructive testing up to 95 % is solved. The comprehensive mine, laboratory and analytical research concerning propagation of acoustic oscillations in the complex structured rock massif with geological faults by using different methods of probing acoustic signal generation are organized and conducted. The mathematical model of spreading acoustic wave packet in the dispersion medium based on the information and amplitude-phase modulation of carrying frequencies of the probing signal is proposed and justified. An effective method of the forecasting hidden disjunctives in coal layers by the method of non-destructive testing is developed. The method is based on the analysis of characteristic emergencies of geological faults in the functions of a signal modulation parameters obtained by acoustic probing of coal-rock massif. The regularities obtained from the research results are used to develop recommendations regarding the tectonic structure of coal layers for mines "Dniprovska", "Krasnolymanska" and "Stepova".

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Лисенко, Юлія Юріївна. "Інформаційно–діагностична система імпульсного вихрострумового неруйнівного контролю виробів машинобудування". Doctoral thesis, Київ, 2017. https://ela.kpi.ua/handle/123456789/21603.

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Дисертація присвячена розробці інформаційно – діагностичної системи імпульсного вихрострумового неруйнівного контролю виробів машинобудування. В роботі проаналізовано процеси в ланцюгах вихрострумового перетворювача в умовах імпульсному режиму збудження та визначено умови виникнення загасаючих гармонічних коливань, що дозволило в якості інформативних параметрів сигналів вихрострумового перетворювача запропонувати використання їх власної частоти та коефіцієнта загасання. В роботі розроблено методику обробки та аналізу інформативних параметрів сигналів вихрострумового перетворювача в імпульсному режимі збудження, в основі якої лежить визначення запропонованих інформативних параметрів цих сигналів через їх амплітудну та фазову характеристики за допомогою застосування перетворення Гільберта. Запропоновано використання експоненційної апроксимації для амплітудної характеристики та лінійного тренду для фазової характеристики сигналу вихрострумового перетворювача для підвищення точності визначення інформативних параметрів цього сигналу. Проведено аналіз похибок визначення частоти власних коливань та коефіцієнта загасання сигналу вихрострумового перетворювача, який дозволив визначити умови отримання мінімальної похибки визначення цих інформативних параметрів сигналу та визначити оптимальний час аналізу, що суттєво впливає на результати контролю в умовах впливу завад і шумів.

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Sergeev, S. A., V. B. Klepikov, and K. V. Mahotilo. "Amplitude-Frequency Characteristic of a Neural Control Based DC Drive." Thesis, 1996. http://repository.kpi.kharkov.ua/handle/KhPI-Press/30477.

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The paper interprets characteristics of a neural-control-based DC servodrive in terms of the classical theory of automatic control. It also touches on the problem of choosing training patterns to synthesize a nonlinear PID-controller with a desired amplitude-frequency characteristic and analyses the efficiency of using for this purpose input signals in form of a step function and a harmonic one. Synthesis of the neurocontroller has been performed within the framework of a three-layer perceptron. To train it, a genetic algorithm has been developed.

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Хомик, Тарас Володимирович, Юрій Васильович Черв`яков, Taras Khomyk та Yurii Chervyakov. "Розробка та дослідження автоматизованої системи контролю амплітудно-частотних характеристик акустичних приладів". Master's thesis, 2020. http://elartu.tntu.edu.ua/handle/lib/33216.

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Роботу виконано на кафедрі ком’пютерно-інтегрованих технологій Тернопільського національного технічного університету імені Івана Пулюя Міністерства освіти і науки України Захист відбудеться 23 грудня 2020 р. о 08 .00 годині на засіданні екзаменаційної комісії № 24 у Тернопільському національному технічному університеті імені Івана Пулюя за адресою: 46001, м. Тернопіль, вул.Руська, 56, навчальний корпус №1, ауд. 403
Хомик Т.В., Червяков Ю.В. Розробка та дослідження автоматизованої системи контролю амплітудно-частотних характеристик акустичних приладів. 151 – «Автоматизація та комп’ютерно-інтегровані технології» – Тернопільський національний технічний університет імені Івана Пулюя. – Тернопіль, 2020. В кваліфікаційній роботі виконано проектування автоматизованої системи для контролю амплітудно-частотних характеристик акустичних приладів. Khomyk T.V, Chervyakov Yu.V. Development and research of the automated system of control of amplitude-frequency characteristics of acoustic devices. 151 – «Automation and Computer-Integrated Technologies». – Ternopil Ivan Pul’uj National Technical University. – Ternopil, 2020. In the qualification work the design of the automated system for control of amplitude-frequency characteristics of acoustic devices is executed
ВСТУП 7 1. АНАЛІТИЧНА ЧАСТИНА 9 1.1. Аналіз відомих технічних рішень, що пов’язані з автоматизацією завдання на проектування 9 1.2. Обґрунтування актуальності автоматизації вибраного напрямку розробки 19 2. ТЕХНОЛОГІЧНА ЧАСТИНА 20 2.1. Загальна характеристика об’єкту автоматизації 20 2.2. Аналіз конструктивних особливостей виробу та технологічних особливостей проведення вимірювань 21 2.3. Аналіз технічних умов на проведення вимірювань параметрів головок динамічних 23 2.4. Розробка технологічного процесу отримання амплітудно-частотної характеристики ГД 26 3. КОНСТРУКТОРСЬКА ЧАСТИНА 30 3.1. Аналіз вихідних даних на проектування інформаційно-вимірювальної системи 30 3.2. Уточнення компоновки автоматизованої інформаційно-вимірювальної системи 31 3.3. Обґрунтування необхідності проектування нестандартного обладнання, що входить в інформаційно-вимірювальну систему 46 3.4. Проектування та розрахунок деталей нестандартного обладнання 47 3.5. Принципи функціонування системи керування 50 3.6. Розрахунок RC- ланок 1/3-октавного фільтра 54 3.7. Опис роботи електричних схем блоків системи 55 3.8. Опис роботи вимірювального комплексу 57 4. НАУКОВО-ДОСЛІДНА ЧАСТИНА 58 4.1. Вимірювання частотних характеристик звукового тиску головок динамічних 58 4.2. Основні електроакустичні показники 59 4.3. Шумові вимірювальні сигнали 63 5. СПЕЦІАЛЬНА ЧАСТИНА 66 5.1. Моделювання роботи людино-машинної системи 66 6. ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 71 6.1. Розробка заходів по безпеці праці у спроектованій системі 71 6.2. Вимоги техніки безпеки до установки, що проектується 72 6.3. Аналіз потенційних небезпек на дільниці, що проектується та заходи по їх зниженню 74 6.4. Безпека життєдіяльності у надзвичайних ситуаціях 75 ВИСНОВКИ 78 ПЕРЕЛІК ПОСИЛАНЬ 79

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Книги з теми "Amplitude-frequency characteristic"

Tibaldi, Stefano, and Franco Molteni. Atmospheric Blocking in Observation and Models. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.611.

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The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.

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Частини книг з теми "Amplitude-frequency characteristic"

Deuschl, G., J. Timmer, H. Genger, C. Gantert, C. H. Lücking, and J. Honerkamp. "Frequency, Amplitude, and Waveform Characteristics of Physiologic and Pathologic Tremors." In Instrumental Methods and Scoring in Extrapyramidal Disorders, 93–100. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-78914-4_9.

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Hu, Cong, Junhao Niu, and Haitao Su. "Automatic Testing Systems for Filter Amplitude-Frequency Characteristics Based on LabVIEW." In Advances in Computer Science, Intelligent System and Environment, 711–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23753-9_115.

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Kohl, O. "Identification of Parameters of Stiffness and Damping Based on the Amplitude Frequency Characteristics." In The Latest Methods of Construction Design, 421–25. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-22762-7_63.

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Junfeng, Chen, and Zhu Jun. "Study on the Amplitude Characteristics of Pitch and Heave Motions for a Ship Based on Frequency Scattering." In Lecture Notes in Electrical Engineering, 157–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19706-2_21.

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Lohar, Hareram, Anirban Mitra, and Sarmila Sahoo. "Effect of Boundary Conditions and Taper Patterns on Geometrically Nonlinear Frequency Response of Axially Graded Beams on Elastic Foundation." In Handbook of Research on Advancements in Manufacturing, Materials, and Mechanical Engineering, 110–40. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4939-1.ch006.

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Forced vibration analysis is performed on a tapered axially functionally graded beam resting on elastic foundation under externally applied harmonic excitations to present the effect of boundary conditions and taper patterns on the frequency response. The elastic foundation is modelled in the present analysis as Winkler foundation. A displacement based semi-analytical method is adopted for mathematical formulation and the derivation of governing equations is carried out following Hamilton's principle. Von Karman nonlinear strain-displacement relation employed to incorporate geometric nonlinearity. Broyden method is adopted to solve the nonlinear set of equations. Frequency response curves are plotted in non-dimensional frequency-amplitude plane to represent nonlinear forced vibration characteristic of the system. New benchmark results are also provided for different combination of system parameters (i.e., excitation amplitudes, foundation stiffness values, material models, taper patterns, and flexural boundary conditions). Operational deflection shapes (ODS) are also presented.

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Tsuji, Toshio, Nan Bu, and Osamu Fukuda. "A Recurrent Probabilistic Neural Network for EMG Pattern Recognition." In Pattern Recognition Technologies and Applications, 370–87. IGI Global, 2008. http://dx.doi.org/10.4018/978-1-59904-807-9.ch017.

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In the field of pattern recognition, probabilistic neural networks (PNNs) have been proven as an important classifier. For pattern recognition of EMG signals, the characteristics usually used are: (1) amplitude, (2) frequency, and (3) space. However, significant temporal characteristic exists in the transient and non-stationary EMG signals, which cannot be considered by traditional PNNs. In this article, a recurrent PNN, called recurrent log-linearized Gaussian mixture network (R-LLGMN), is introduced for EMG pattern recognition, with the emphasis on utilizing temporal characteristics. The structure of R-LLGMN is based on the algorithm of a hidden Markov model (HMM), which is a routinely used technique for modeling stochastic time series. Since R-LLGMN inherits advantages from both HMM and neural computation, it is expected to have higher representation ability and show better performance when dealing with time series like EMG signals. Experimental results show that R-LLGMN can achieve high discriminant accuracy in EMG pattern recognition.

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Berber, Stevan. "Digital Bandpass Modulation Methods." In Discrete Communication Systems, 215–304. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198860792.003.0006.

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This chapter presents mathematical models of baseband and bandpass digital communication systems based on binary and quaternary phase-shift keying, frequency-shift keying, and quadrature amplitude modulation. The systems are deduced as special cases from the general generic system structure and the related theory of orthonormal basis functions. The systems are uniquely presented using mathematical operators and detailed derivatives for signals in time and frequency domains at the system’s vital points, that is, the transmitter, the receiver, and the noise generator, using the concepts of both stochastic (continuous and discrete) and deterministic (continuous and discrete) signal processing. The vital characteristics of the system and its blocks are expressed in terms of amplitude spectral density, autocorrelation functions, power and energy spectral densities, and bit error probability.

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Zekeridou, Anastasia, and Vanda A. Lennon. "Difficulty Climbing the Stairs." In Mayo Clinic Cases in Neuroimmunology, edited by Andrew McKeon, B. Mark Keegan, and W. Oliver Tobin, 149–51. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780197583425.003.0048.

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A 72-year-old woman with a history of rheumatoid arthritis and chronic obstructive pulmonary sought care for a 3-month history of progressive difficulty walking on uneven terrain and climbing stairs. In the 2 preceding weeks, she also noted difficulty standing up from a seated position. She reported no sensory symptoms but recently noticed dry mouth and new-onset constipation with decreased appetite. Electromyography showed diffusely low-amplitude compound muscle action potential responses to single-nerve stimuli at rest, with normal sensory nerve action potentials. Studies of the ulnar and femoral motor nerves demonstrated a decrement to low-frequency repetitive stimulation (12%) and substantial postexercise facilitation (200%) and decrement repair. The serum was positive for cyclic citrullinated peptide antibody, rheumatoid factor, and P/Q-type voltage-gated calcium channel antibody. Computed tomography of the chest showed subcarinal and right hilar lymphadenopathy without evidence of a primary lesion, with avidity on ¹⁸F-fludeoxyglucose–positron emission tomography/computed tomography. Transbronchial fine-needle aspiration biopsy of the lymph node revealed small cell lung carcinoma. The patient was diagnosed with Lambert-Eaton myasthenic syndrome and small cell lung carcinoma. Concurrent chemotherapy and radiation were administered for the small cell lung carcinoma, with some improvement of the patient’s weakness. Symptomatic treatment for Lambert-Eaton myasthenic syndrome was initiated. Therapy with 3,4-diaminopyridine improved the patient’s weakness, but her daily activities were limited by persistent, moderate, lower extremity weakness. The weakness objectively improved with intravenous immunoglobulin therapy. Two years later, the patient was maintained on 3,4-diaminopyridine and monthly intravenous immunoglobulin, with minimal persistent weakness and no evidence of cancer recurrence. Lambert-Eaton myasthenic syndrome was first described at Mayo Clinic in 1956 as a “myasthenic syndrome associated with malignant tumors” that had characteristic electromyographic findings, later shown to be presynaptic by microelectrophysiologic testing.

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Berber, Stevan. "Discrete Bandpass Modulation Methods." In Discrete Communication Systems, 305–85. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198860792.003.0007.

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This chapter presents mathematical models of discrete baseband and bandpass communication systems based on binary phase-shift keying, quaternary phase-shift keying, frequency-shift keying, and quadrature amplitude modulation. The operation of intermediate-frequency systems where all processing is performed in the discrete-time domain are presented. The systems are deduced as special cases from a generic system structure that is based on the application of orthonormal basis functions. The block schematics of systems are uniquely presented using mathematical operators. Detailed derivatives are presented for signals in the discrete-time domain at the vital points of the system’s structure, using the concepts of both discrete stochastic and discrete deterministic signal processing. The vital characteristics of the discrete system and its blocks are expressed in terms of amplitude spectral density, autocorrelation functions, power and energy spectral densities, and bit error probability.

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Fang, Jian, Wenwen Zheng, and Xiaoyan Lei. "Experimental Study on Characteristics of Short Wave Irregularity in Urban Rail Transit." In Advances in Transdisciplinary Engineering. IOS Press, 2020. http://dx.doi.org/10.3233/atde200223.

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Based on the measured irregularity data of Shanghai rail transit 11# line, firstly from the angle of time domain the amplitude stability and amplitude distribution characteristics of the rail surface short wave irregularity whose wavelengths are in the range of 0.01 ∼ 1 m are analyzed. Secondly from the point of view of frequency domain by using the maximum entropy spectrum method the short wave power spectral density is estimated. Then the power spectral density curves are compared with the short spectrum of Wang Lan and Sato and the different track structure effects on the states of the rail surface irregularities are also analyzed. The research show that the amplitude distribution of track surface short wave irregularity is close to the normal distribution. And the maximum amplitudes of some sections in Jiading Xincheng – Malu and Nanxiang – Taopu saemaul undong exceed 2.0mm. In the section of Liziyuan-Shanghai West Railway Station, the power spectral density curves of track structure with the supporting block, DTIII-2 type fasteners and with the conventional integral track bed are also similar to that of Sato spectrum. And it is obviously superior to that of other track structures in this section.

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Тези доповідей конференцій з теми "Amplitude-frequency characteristic"

Lee, Jie, Zhixiang Lin, Weizun Zheng, Zefeng Wang, and Jing Liu. "A Remote Amplitude Frequency Characteristic Testing Device." In 2017 International Conference on Information, Communication and Engineering (ICICE). IEEE, 2017. http://dx.doi.org/10.1109/icice.2017.8479209.

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Semenov, E., V. Posadskiy, V. Tyazhlov, Yu Kuzmin, and A. Kovalchuk. "Super Broadband Frequency Converter with Controlled Amplitude-Frequency Characteristic." In 2006 16th International Crimean Microwave and Telecommunication Technology. IEEE, 2006. http://dx.doi.org/10.1109/crmico.2006.256320.

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Semenov, E. A., V. N. Posadskiy, V. S. Tyazhlov, Yu a. Kuzmin, and A. G. Kovalchuk. "Super Broadband Frequency Converter with Controlled Amplitude-Frequency Characteristic." In 2006 International Conference on Actual Problems of Electron Devices Engineering. IEEE, 2006. http://dx.doi.org/10.1109/apede.2006.307391.

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Han, Mingming, Bo Chen, Zhaoliang Gu, and Jihao Wang. "Amplitude frequency characteristic of TEV in substation with RCD." In 2020 5th Asia Conference on Power and Electrical Engineering (ACPEE). IEEE, 2020. http://dx.doi.org/10.1109/acpee48638.2020.9136213.

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Klaerner, Matthias, Mario Wuehrl, Lothar Kroll, and Steffen Marburg. "Characteristic amplitude-frequency functions of the radiated sound power." In 173rd Meeting of Acoustical Society of America and 8th Forum Acusticum. Acoustical Society of America, 2017. http://dx.doi.org/10.1121/2.0000549.

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Han, Shangyan, Yue Wu, Xiangli Zeng, Zhigang Yang, Guoren Zhu, Yanhu Shen, and Jiang Su. "Analysis of the Amplitude-Frequency characteristic of helical feeder." In 2020 7th International Conference on Information Science and Control Engineering (ICISCE). IEEE, 2020. http://dx.doi.org/10.1109/icisce50968.2020.00333.

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Chen, Bingyan, Juan Zhou, Rong Shi, and Mingyuan Xin. "Development and application on amplitude-frequency characteristic detection instrument of filter." In Instruments (ICEMI). IEEE, 2009. http://dx.doi.org/10.1109/icemi.2009.5274175.

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Ke, Liu, Tian shulin, and Xiao Yindong. "A Method Of Amplitude-Frequency Characteristic Compensation About DDS Signal Source." In 2007 8th International Conference on Electronic Measurement and Instruments. IEEE, 2007. http://dx.doi.org/10.1109/icemi.2007.4351264.

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Bodrenkov, Evgeny A., Elena Y. Kochetkova, Alla A. Lebedeva, and Aleksandra N. Modulina. "Synthesis of Bandpass Filters with an Arithmetic Symmetric Amplitude-Frequency Characteristic." In 2021 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (ElConRus). IEEE, 2021. http://dx.doi.org/10.1109/elconrus51938.2021.9396192.

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Titov, D. A., A. S. Tabakova, and I. V. Yunkin. "Amplitude-Frequency Characteristic of the Device for Measuring Estimates of the Characteristic Function of Signal." In 2021 Dynamics of Systems, Mechanisms and Machines (Dynamics). IEEE, 2021. http://dx.doi.org/10.1109/dynamics52735.2021.9653698.

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Звіти організацій з теми "Amplitude-frequency characteristic"

Rahman, Shahedur, Rodrigo Salgado, Monica Prezzi, and Peter J. Becker. Improvement of Stiffness and Strength of Backfill Soils Through Optimization of Compaction Procedures and Specifications. Purdue University, 2020. http://dx.doi.org/10.5703/1288284317134.

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Vibration compaction is the most effective way of compacting coarse-grained materials. The effects of vibration frequency and amplitude on the compaction density of different backfill materials commonly used by INDOT (No. 4 natural sand, No. 24 stone sand, and No. 5, No. 8, No. 43 aggregates) were studied in this research. The test materials were characterized based on the particle sizes and morphology parameters using digital image analysis technique. Small-scale laboratory compaction tests were carried out with variable frequency and amplitude of vibrations using vibratory hammer and vibratory table. The results show an increase in density with the increase in amplitude and frequency of vibration. However, the increase in density with the increase in amplitude of vibration is more pronounced for the coarse aggregates than for the sands. A comparison of the maximum dry densities of different test materials shows that the dry densities obtained after compaction using the vibratory hammer are greater than those obtained after compaction using the vibratory table when both tools were used at the highest amplitude and frequency of vibration available. Large-scale vibratory roller compaction tests were performed in the field for No. 30 backfill soil to observe the effect of vibration frequency and number of passes on the compaction density. Accelerometer sensors were attached to the roller drum (Caterpillar, model CS56B) to measure the frequency of vibration for the two different vibration settings available to the roller. For this roller and soil tested, the results show that the higher vibration setting is more effective. Direct shear tests and direct interface shear tests were performed to study the impact of particle characteristics of the coarse-grained backfill materials on interface shear resistance. The more angular the particles, the greater the shear resistance measured in the direct shear tests. A unique relationship was found between the normalized surface roughness and the ratio of critical-state interface friction angle between sand-gravel mixture with steel to the internal critical-state friction angle of the sand-gravel mixture.

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