A High-Speed Fourth-Order Nested Bus-Splitting Error Feedback Modulator

2012 ◽  
Author(s):  
Hongjia Mo ◽  
M.P. Kennedy
Keyword(s):  
Fourth Order ◽  
High Speed ◽  
Error Feedback ◽  
Feedback Modulator

scholarly journals Effect of the turning characteristics of underfloor wheel lathes on the evolution of wheel polygonisation

2018 ◽  
Vol 233 (5) ◽  
pp. 479-488 ◽  
Author(s):  
Dabin Cui ◽  
Boyang An ◽  
Paul Allen ◽  
Ruichen Wang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Fourth Order ◽  
High Speed ◽  
Higher Order ◽  
Ride Quality ◽  
Sustained Use ◽  
High Speed Trains ◽  
Cut Quality ◽  
Multiple Unit ◽  
Component Failures

During both running and wheel cut operations, wheels of railway vehicles and the friction rollers that support and drive the wheelset on a typical wheel cut lathe are subject to wear and hence are likely to develop out-of-round characteristics after sustained use. The resulting out-of-round wheels can significantly affect the ride quality and can potentially increase the incidence of fatigue-related component failures due to the resulting higher intensity loading cycles. Furthermore, the corresponding out-of-round characteristics of the lathe's friction rollers will continue to degrade the subsequent cut quality of wheels. For the analysis of the out-of-round characteristics caused by an underfloor wheel lathe used for the high-speed trains in China, a mathematical model based on a typical electric multiple unit (EMU) vehicle's wheelsets and their interactions with the wheel lathe friction rollers was established. Factors influencing the cut quality of the wheels, including the number of cuts, eccentricity forms of the friction rollers and the longitudinal spacing of the two rollers, have been analysed. The results show that two cuts can effectively remove the higher order polygon on the wheel surface. The eccentricity and phase angle of the friction rollers have no influence on the cut quality of higher order polygons, whereas they are the primary cause for the fourth-order polygons. The severity of the fourth-order polygon depends on the level and the phase of the eccentricity of the friction rollers. The space of the two rollers can also significantly affect the cut quality. Obtaining the theoretical and practical value for the maintenance of polygonised wheels using the underfloor lathe is the main outcome of this study.

A Differentially Quantized Bandpass Error Feedback Modulator for ADCs in Digital Radio

2018 ◽  
Vol 37 (10) ◽  
pp. 4181-4199 ◽  
Author(s):  
Rijo Sebastian ◽  
A. V. Jos Prakash ◽  
Babita R. Jose ◽  
Jimson Mathew
Keyword(s):  
Error Feedback ◽  
Digital Radio ◽  
Feedback Modulator

High-order moments of Reynolds shear stress fluctuations in a turbulent boundary layer

1973 ◽  
Vol 58 (3) ◽  
pp. 581-593 ◽  
Author(s):  
R. A. Antonia ◽  
J. D. Atkinson
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Turbulent Boundary Layer ◽  
Fourth Order ◽  
High Speed ◽  
Reynolds Shear Stress ◽  
Digital Data ◽  
Normal Velocity ◽  
The Third ◽  
Digital Data Acquisition System

The cumulant-discard approach is used to predict the third- and fourth-order moments and the probability density of turbulent Reynolds shear stress fluctuations uv, the streamwise and normal velocity fluctuations being represented by u and v respectively. Measurements of these quantities in a turbulent boundary layer are presented, with the required statistics of uv obtained by the use of a high-speed digital data-acquisition system. Including correlations between u and u up to the fourth order, the cumulant-discard predictions are in close agreement with the measurements in the inner region of the layer but only qualitatively follow the experimental results in the outer intermittent region. In this latter region, predictions for the third- and fourth-order moments of uv are also obtained by assuming that the properties of both turbulent and irrotational fluctuations are Gaussian and by using some of the available conditional averages of u, v and uv.

Some measurements of multi-point time correlations in grid turbulence

1970 ◽  
Vol 41 (1) ◽  
pp. 169-178 ◽  
Author(s):  
C. W. Van Atta ◽  
T. T. Yeh
Keyword(s):  
Fourth Order ◽  
High Speed ◽  
Longitudinal Velocity ◽  
Joint Probability ◽  
Grid Turbulence ◽  
Odd Order ◽  
Probability Densities ◽  
Even Order ◽  
Point Correlation ◽  
Non Gaussian

Three-point odd-order correlations and four-point even-order correlations of the longitudinal velocity fluctuations in grid-generated turbulence have been measured using linearized hot-wire anemometry, digital sampling, and a high-speed digital computer. The measured correlations are compared with relations between higher-order correlations corresponding to non-Gaussian Gram-Charlier joint probability densities for three and four variables. The fourth-order, three-point Gram-Charlier distribution accurately describes the relation between measured odd-order three-point correlations. The measured fourth-order even-order correlations may be accurately predicted from the two-point correlation using Millionshtchikov's joint-Gaussian hypothesis, except for small values of the separations. The disagreement at small separations cannot be reduced through use of the Gram-Charlier approximation.

Study on Tractor-Semitrailer Shimmy of High Speed

2012 ◽  
Vol 433-440 ◽  
pp. 7420-7424
Author(s):  
Mei Zhi Xie ◽  
Bei Li ◽  
Chao Yi Wei ◽  
Feng Yan Yi
Keyword(s):  
Transfer Function ◽  
Dynamic Model ◽  
Fourth Order ◽  
High Speed ◽  
Damping Ratio ◽  
Second Order ◽  
Original Model ◽  
The Third

Through the establishment of dynamic model of tractor-semitrailer, calculate its transfer function. In the case of the third and fourth state of balanced coefficient is very small in the original model, the model of the tractor-semitrailer of fourth-order drop for second-order using MATLAB-modred () function and balreal () function, seek of relationship between damping ratio and the speed of tractor-semitrailer, The results show that: the tractor-semitrailer shimmy of high-speed is speed inversely proportional to the damping ratio, the higher the speed, the smaller the damping ratio, and thus more likely to shock and shimmy.

scholarly journals Riemann–Hilbert Problem Associated with the Fourth-Order Dispersive Nonlinear Schrödinger Equation in Optics and Magnetic Mechanics

2021 ◽  
Vol 28 (4) ◽  
pp. 414-435
Author(s):  
Beibei Hu ◽  
Ling Zhang ◽  
Qinghong Li ◽  
Ning Zhang
Keyword(s):  
Fourth Order ◽  
High Speed ◽  
Hilbert Problem ◽  
Ultrashort Pulses ◽  
Initial Boundary ◽  
Dipole Interaction ◽  
Spin Excitation ◽  
Nonlinear Schrödinger ◽  
Function Solution ◽  
Initial Boundary Value

AbstractIn this paper, by using Fokas method, we study the initial-boundary value problems (IBVPs) of the fourth-order dispersive nonlinear Schrödinger (FODNLS) equation on the half-line, which can simulate the nonlinear transmission and interaction of ultrashort pulses in the high-speed optical fiber transmission system, and can also describe the nonlinear spin excitation phenomenon of one-dimensional Heisenberg ferromagnetic chain with eight poles and dipole interaction. By discussing the eigenfunctions of Lax pair of FODNLS equation and analyzing symmetry of the scattering matrix, we get a matrix Riemann–Hilbert (RH) problem from for the IBVPs of FODNLS equation. Moreover, we get the potential function solution u(x, t) of the FODNLS equation by solving this matrix RH problem. In addition, we also obtain that some spectral functions satisfy an important global relation.

Selection of shape for turnout curve of high-speed switches

2020 ◽  
pp. 62-67
Author(s):  
Alexey Alexeevich Loktev ◽  
◽  
Vadim Vadimovich Korolev ◽  
Irina Viktorovna Shishkina ◽  
Vladislav Sergeevich Kuskov ◽  
...  
Keyword(s):  
Fourth Order ◽  
High Speed ◽  
Comparative Assessment ◽  
Centrifugal Acceleration ◽  
Variable Radius ◽  
Sine Curve ◽  
Selection Of ◽  
Main Factor

The main factor at determination of radius of turnout curve under the conditions of comfortable driving is the limitation of centrifugal acceleration increment amount per unit time. For this reason, at designing high-speed switches it is advisable to use variable-radius curves as a turnout curve. The paper considers variable-radius curves - cubic parabola, parabola of the fourth order and sine curve. On the basis of the comparative assessment it is established that the sine curve is the most acceptable variant for using as a turnout curve in high-speed switches.

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