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On the Fourth Moment of Coefficients of Symmetric Square L-Function
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作者 Huixue LAO 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2012年第6期877-888,共12页
t Let f(z) be a holomorphic Hecke eigencuspform of weight k for the full mod- ular group. Let Af(n) be the nth normalized Fourier coefficient of f(z). Suppose that L(sym2f, s) is the symmetric square L-functio... t Let f(z) be a holomorphic Hecke eigencuspform of weight k for the full mod- ular group. Let Af(n) be the nth normalized Fourier coefficient of f(z). Suppose that L(sym2f, s) is the symmetric square L-function associated with f(z), and Asym2f(n) de- notes the nth coefficient L(sym2f, s). In this paper, it is proved that where P2 (t) is a polynomial in t of degree 2. Similarly, it is obtained that where P2(t) is a polynomial in t of degree 2. 展开更多
关键词 Fourier coefficient of cusp form symmetric power l-function Rankin-Selberg l-function
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Oscillations of coefficients of symmetric square L-functions over primes
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作者 Fei HOU 《Frontiers of Mathematics in China》 SCIE CSCD 2015年第6期1325-1341,共17页
Let L(s, sym2f) be the symmetric-square L-function associated to a primitive holomorphic cusp form f for SL(2, Z), with tf(n, 1) denoting the nthcoefficient of the Dirichlet series for it. It is proved that, for... Let L(s, sym2f) be the symmetric-square L-function associated to a primitive holomorphic cusp form f for SL(2, Z), with tf(n, 1) denoting the nthcoefficient of the Dirichlet series for it. It is proved that, forN≥2and anyα∈ there exists an effective positive constant c such that ∑n≤N∧(n)tf(n,1)e(nα)〈〈N exp (-c√logN,where ∧(n) is the von Mangoldt function, and the implied constant only depends on f. We also study the analogue of Vinogradov's three primes theorem associated to the coefficients of Rankin-Selberg L-functions. 展开更多
关键词 symmetric-square l-function primitive holomorphic cusp form Fourier coefficient
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Constructing Pandiagonal Snowflake Magic Squares of Odd Order 被引量:3
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作者 ZHANGShi-de HUQing-wen WANGJi-zhao 《Chinese Quarterly Journal of Mathematics》 CSCD 2004年第2期172-185,共14页
The constructional methods of pandiagonal snowflake magic squares of orders 4m are established in paper [3]. In this paper, the constructional methods of pandiagonal snowflake magic squares of odd orders n are establi... The constructional methods of pandiagonal snowflake magic squares of orders 4m are established in paper [3]. In this paper, the constructional methods of pandiagonal snowflake magic squares of odd orders n are established with n = 6m+l, 6m+5 and 6m+3, m is an odd positive integer and m is an even positive integer 9|6m + 3. It is seen that the number sets for constructing pandiagonal snowflake magic squares can be extended to the matrices with symmetric partial difference in each direction for orders 6m + 1 , 6m + 5; to the trisection matrices with symmetric partial difference in each direction for order 6m + 3. 展开更多
关键词 pandiagonal magic squares matrix with uniform partial difference in each direction matrix with symmetric partial difference in each direction trisection matrix with uniform partial difference in each direction semi-pandiagonal Latin square
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LARGE EDDY SIMULATION AND SPECTRUM ANALYSIS OF FLOW AROUND TWO SQUARE CYLINDERS ARRANGED SIDE BY SIDE
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作者 魏英杰 朱蒙生 何钟怡 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第8期903-910,共8页
Large eddy simulation cooperated with the second order full extension ETG(Euler-Taylor-Galerkin) finite element method was applied to simulate the flow around two square cylinders arranged side by side at a spacing ra... Large eddy simulation cooperated with the second order full extension ETG(Euler-Taylor-Galerkin) finite element method was applied to simulate the flow around two square cylinders arranged side by side at a spacing ratio of (1.5.) The second order full extension ETG finite element method was developed by Wang and He. By means of Taylor expansion of terms containing time derivative, time derivative is replaced by space derivative. The function of it is equal to introducing an artificial viscosity term. The streamlines of the flow at different moments were obtained. The time history of drag coefficient, lift coefficient and the streamwise velocity on the symmetrical points were presented. Furthermore, the symmetrical problem of the frequency spectrum of flow around two square cylinders arranged side by side were studied by using the spectral analysis technology. The data obtained at the initial stage are excluded in order to avoid the influence of initial condition on the results. The power spectrums of drag coefficient, lift coefficient, the streamwise velocity on the symmetrical points were analyzed respectively. The results show that although the time domain process of dynamic parameters is non-symmetrical, the frequency domain process of them is symmetrical under the symmetrical boundary conditions. 展开更多
关键词 two square cylinders arranged side by side symmetrical flow around body spectrum analysis large eddy simulation ETG finite element drag coefficient lift coefficient
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Asymptotic Properties of Estimators for Ornstein-Uhlenbeck Processes with Small Symmetricα-Stable Motions
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作者 PAN Yurong JIA Chaoyong LIU Xiaoyan 《Journal of Donghua University(English Edition)》 EI CAS 2020年第4期357-364,共8页
The asymptotic behaviors for estimators of the drift parameters in the Ornstein-Uhlenbeck process driven by small symmetricα-stable motion are studied in this paper.Based on the discrete observations,the conditional ... The asymptotic behaviors for estimators of the drift parameters in the Ornstein-Uhlenbeck process driven by small symmetricα-stable motion are studied in this paper.Based on the discrete observations,the conditional least squares estimators(CLSEs)of all the parameters involved in the Ornstein–Uhlenbeck process are proposed.We establish the consistency and the asymptotic distributions of our estimators asεgoes to 0 and n goes to∞simultaneously. 展开更多
关键词 Ornstein-Uhlenbeck process symmetricα-stable motion conditional least squares estimator(CLSE) consistency asymptotic distribution
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Squares from D(-4)and D(20)Triples
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作者 Zvonko Cerin 《Advances in Pure Mathematics》 2011年第5期286-294,共9页
We study the eight infinite sequences of triples of natural numbers A=(F2n+1,4F2n+3,F2n+7), B=(F2n+1,4F2n+5,F2n+7), C=(F2n+1,5F2n+1,F2n+3), D=(F2n+3,4F2n+1,F2n+3) and A=(L2n+1,4L2n+3,L2n+7), B=(L2n+1,4L2n+5,L2n+7), C=... We study the eight infinite sequences of triples of natural numbers A=(F2n+1,4F2n+3,F2n+7), B=(F2n+1,4F2n+5,F2n+7), C=(F2n+1,5F2n+1,F2n+3), D=(F2n+3,4F2n+1,F2n+3) and A=(L2n+1,4L2n+3,L2n+7), B=(L2n+1,4L2n+5,L2n+7), C=(L2n+1,5L2n+1,L2n+3), D=(L2n+3,4L2n+1,L2n+3. The sequences A,B,C and D are built from the Fibonacci numbers Fn while the sequences A, B, C and D from the Lucas numbers Ln. Each triple in the sequences A,B,C and D has the property D(-4) (i. e., adding -4 to the product of any two different components of them is a square). Similarly, each triple in the sequences A, B, C and D has the property D(20). We show some interesting properties of these sequences that give various methods how to get squares from them. 展开更多
关键词 Fibonacci Numbers Lucas Numbers square symmetric Sum Alternating Sum Product Component
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Least-Squares Solutions of Generalized Sylvester Equation with Xi Satisfies Different Linear Constraint
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作者 Xuelin Zhou Dandan Song +1 位作者 Qingle Yang Jiaofen Li 《Advances in Linear Algebra & Matrix Theory》 2016年第2期59-74,共16页
In this paper, an iterative method is constructed to find the least-squares solutions of generalized Sylvester equation , where is real matrices group, and satisfies different linear constraint. By this iterative meth... In this paper, an iterative method is constructed to find the least-squares solutions of generalized Sylvester equation , where is real matrices group, and satisfies different linear constraint. By this iterative method, for any initial matrix group within a special constrained matrix set, a least squares solution group with  satisfying different linear constraint can be obtained within finite iteration steps in the absence of round off errors, and the unique least norm least-squares solution can be obtained by choosing a special kind of initial matrix group. In addition, a minimization property of this iterative method is characterized. Finally, numerical experiments are reported to show the efficiency of the proposed method. 展开更多
关键词 Least-squares Problem Centro-symmetric Matrix Bisymmetric Matrix Iterative Method
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加肋对称层合板线性弯曲分析的移动最小二乘无网格法
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作者 韦冬炎 陈卫 +1 位作者 杨健生 彭林欣 《应用力学学报》 北大核心 2025年第2期425-433,共9页
基于一阶剪切变形理论,提出了一种求解矩形加肋对称层合板线性弯曲问题的移动最小二乘无网格法。加肋层合板可以视为层合板和肋条组合而成的复合结构。采用移动最小二乘法近似分别建立层合板和肋条的位移场,推导出层合板和肋条的刚度矩... 基于一阶剪切变形理论,提出了一种求解矩形加肋对称层合板线性弯曲问题的移动最小二乘无网格法。加肋层合板可以视为层合板和肋条组合而成的复合结构。采用移动最小二乘法近似分别建立层合板和肋条的位移场,推导出层合板和肋条的刚度矩阵,再利用板与肋条间的位移协调条件,将肋条的刚度矩阵叠加到层合板的刚度矩阵中,得到整个复合结构的刚度矩阵。由于基于移动最小二乘近似的无网格法,不满足克罗内克条件,故采用完全转换法处理本质边界条件。文末算例分析了不同肋条数量,铺层方式,弹性模量比和宽厚比下的加肋层合板弯曲性能,并将本研究解与ABAQUS解进行对比,验证了本研究方法的有效性及准确性。 展开更多
关键词 加肋对称层合板 线性弯曲 完全转换法 移动最小二乘法
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一种对称Farrow结构分数时延滤波器设计方法
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作者 贾可新 陈阳 《雷达科学与技术》 北大核心 2025年第4期417-423,432,共8页
为了通过控制滤波器频率响应逼近精度,尽可能降低实现结构的复杂度,获得滤波器系数的全局最优解,提出了一种基于二阶锥规划的对称Farrow结构分数时延滤波器设计方法。这种方法根据FIR滤波器的线性相位特性,构建加权最小二乘拟合目标函... 为了通过控制滤波器频率响应逼近精度,尽可能降低实现结构的复杂度,获得滤波器系数的全局最优解,提出了一种基于二阶锥规划的对称Farrow结构分数时延滤波器设计方法。这种方法根据FIR滤波器的线性相位特性,构建加权最小二乘拟合目标函数和频率响应误差约束条件,并将约束转化为线性不等式约束,可将对称Farrow结构分数时延滤波器设计转化为一个凸优化求解问题。该问题可利用二阶锥规划方法进行求解,获得满足幅频和相频误差约束的全局最优滤波器系数。通过在仿真实验中对比分析所提方法与其他4种方法,验证了所提方法的有效性。 展开更多
关键词 分数时延滤波器 对称Farrow结构 二阶锥规划 加权最小二乘 频率响应
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数理统计教学中关于卡方分布的两个问题
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作者 顾蓓青 张澍轶 +1 位作者 王蓉华 徐晓岭 《高等数学研究》 2025年第1期57-60,共4页
针对数理统计教学中关于卡方分布的两个反问题,即若随机变量X=Y^(2)~χ^(2)(1),且Y在(-∞,+∞)上取值,则Y服从N(0,1)是否一定成立(问题一)若随机变量Z与X相互独立,且X=Y^(2)~χ^(2)(1),且Y在(-∞,+∞)上取值,则Z与Y相互独立是否成立(问... 针对数理统计教学中关于卡方分布的两个反问题,即若随机变量X=Y^(2)~χ^(2)(1),且Y在(-∞,+∞)上取值,则Y服从N(0,1)是否一定成立(问题一)若随机变量Z与X相互独立,且X=Y^(2)~χ^(2)(1),且Y在(-∞,+∞)上取值,则Z与Y相互独立是否成立(问题二)通过反例说明问题结论不成立,给出了问题成立的条件,并给出了相应的证明过程. 展开更多
关键词 费歇定理 卡方分布 对称型分布 边际密度 联合密度
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一种基于ZP-OTFS的低复杂度SSOR检测算法
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作者 何茂恒 张薇 《电讯技术》 北大核心 2025年第2期223-230,共8页
针对高速移动场景中正交时频空间(Orthogonal Time Frequency Space, OTFS)系统线性最小均方误差(Linear Minimum Mean Square Error, LMMSE)检测复杂度过高而难以快速有效实现的问题,利用零填充(Zero Padding, ZP)OTFS系统时域信道矩... 针对高速移动场景中正交时频空间(Orthogonal Time Frequency Space, OTFS)系统线性最小均方误差(Linear Minimum Mean Square Error, LMMSE)检测复杂度过高而难以快速有效实现的问题,利用零填充(Zero Padding, ZP)OTFS系统时域信道矩阵呈块对角稀疏特性提出一种逐块迭代的对称逐次超松弛(Symmetric Successive over Relaxation, SSOR)迭代算法,在降低系统复杂度的同时获得与LMMSE检测近似的性能。仿真结果表明,与逐次超松弛(Successive over Relaxation, SOR)算法相比,所提算法对松弛参数不敏感且具有更快的收敛速度,在迭代次数为10次时误码性能几乎达到LMMSE误码性能,显著降低了检测器的复杂度。 展开更多
关键词 ZP-OTFS 线性最小均方误差(LMMSE) 信号检测 SSOR迭代检测
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LEAST-SQUARES SOLUTION OF AXB = DOVER SYMMETRIC POSITIVE SEMIDEFINITE MATRICES X 被引量:18
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作者 AnpingLiao ZhongzhiBai 《Journal of Computational Mathematics》 SCIE CSCD 2003年第2期175-182,共8页
Least-squares solution of AXB = D with respect to symmetric positive semidefinite matrix X is considered. By making use of the generalized singular value decomposition, we derive general analytic formulas, and present... Least-squares solution of AXB = D with respect to symmetric positive semidefinite matrix X is considered. By making use of the generalized singular value decomposition, we derive general analytic formulas, and present necessary and sufficient conditions for guaranteeing the existence of the solution. By applying MATLAB 5.2, we give some numerical examples to show the feasibility and accuracy of this construction technique in the finite precision arithmetic. 展开更多
关键词 Least-squares solution Matrix equation symmetric positive semidefinite ma- trix Generalized singular value decomposition.
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The Fine Structures of Three Symmetric Latin Squares with Even Orders
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作者 Er Qiang FENG Yan Xun CHANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2011年第6期1137-1148,共12页
Denote by SFin(v) the set of all integer pairs (t, s) for which there exist three symmetric Latin squares of order v on the same set having fine structure (t, s). We completely determine the set SFin(2n) for a... Denote by SFin(v) the set of all integer pairs (t, s) for which there exist three symmetric Latin squares of order v on the same set having fine structure (t, s). We completely determine the set SFin(2n) for any integer n ≥ 5. 展开更多
关键词 symmetric Latin square symmetric Latin trade fine structure
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一种高效的神经肌肉电刺激系统设计
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作者 刘东鸣 王妙 +2 位作者 乔峰 窦唯波 郭春花 《电子技术应用》 2024年第8期102-107,共6页
设计了一种高效的神经肌肉电刺激(Neuromuscular Electrical Stimulation,NMES)系统。NMES的工作原理是利用神经细胞的电兴奋性,通过脉冲电流刺激支配肌肉的神经,从而使肌肉收缩。系统由干电池供电,降压和升压电路采用高效的方案从而来... 设计了一种高效的神经肌肉电刺激(Neuromuscular Electrical Stimulation,NMES)系统。NMES的工作原理是利用神经细胞的电兴奋性,通过脉冲电流刺激支配肌肉的神经,从而使肌肉收缩。系统由干电池供电,降压和升压电路采用高效的方案从而来降低功耗,以STM32F4单片机为主控芯片,产生用于控制刺激强度的DAC信号,以及复用开关的控制信号,经过由复用开关、恒流源、H桥组成的复用恒流源电路,产生分时的电流刺激,从而有效降低系统功耗和设备体积。 展开更多
关键词 神经肌肉电刺激(NMES) 恒流源 低功耗 双相对称方波 复用开关
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对称幂平方L-函数Fourier系数的高次均值估计
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作者 王盼 《兰州文理学院学报(自然科学版)》 2024年第5期8-13,共6页
设f(z)为全模群SL(2,Z)上权为偶数k的Hecke特征形式,L(s,sym^(2)f)为其对应的对称幂平方L-函数,λsym^(2)f(n)为对称幂平方L-函数L(s,sym^(2)f)的Fourier展开式中第n个正规化Fourier系数.本文借助Newton和Thorne近期关于函数Symjf的重... 设f(z)为全模群SL(2,Z)上权为偶数k的Hecke特征形式,L(s,sym^(2)f)为其对应的对称幂平方L-函数,λsym^(2)f(n)为对称幂平方L-函数L(s,sym^(2)f)的Fourier展开式中第n个正规化Fourier系数.本文借助Newton和Thorne近期关于函数Symjf的重要工作以及自守L-函数的亚凸界和均值估计结果,研究了λsym^(2)f(n)在四个整数平方和序列上的三次均值估计和四次均值估计,得到了均值估计的渐近公式,改进了之前的结果. 展开更多
关键词 Hecke特征形式 对称幂平方L-函数 FOURIER系数 四个整数平方和序列
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Double square moments and subconvexity bounds for Rankin-Selberg L-functions of holomorphic cusp forms
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作者 Jianya Liu Haiwei Sun Yangbo Ye 《Science China Mathematics》 SCIE CSCD 2020年第5期823-844,共22页
Let f and g be holomorphic cusp forms of weights k1 and k2 for the congruence subgroups TO(N1)and Γ0(N2),respectively.In this paper the square moment of the Rankin-Selberg L-function for f and g in the aspect of both... Let f and g be holomorphic cusp forms of weights k1 and k2 for the congruence subgroups TO(N1)and Γ0(N2),respectively.In this paper the square moment of the Rankin-Selberg L-function for f and g in the aspect of both weights in short intervals is bounded,when k1^ε <<k^2<<k1^1-ε.These bounds are the mean Lindelof hypothesis in one case and subconvexity bounds on average in other cases.These square moment estimates also imply subconvexity bounds for individual L(1/2+it,f×g) for all g when f is chosen outside a small exceptional set.In the best case scenario the subconvexity bound obtained reaches the Weyl-type bound proved by Lau et al.(2006) in both the k1 and k2 aspects. 展开更多
关键词 automorphic l-function congruence subgroup cusp form holomorphic cusp form Rankin-Selberg l-function square moment subconvexity bound
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基于极点对称模态分解的GNSS测站速度估计方法
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作者 刘开红 《北京测绘》 2024年第11期1608-1613,共6页
全球导航卫星系统(GNSS)测站速度是描述地壳运动的重要指标。本研究旨在通过高精度分析方法提升地壳运动监测的精度,基于日本地区两个GNSS测站(G178和J753)2016年至2023年东(East,E)、北(North,N)和高程(Up,U)方向的坐标时间序列数据,... 全球导航卫星系统(GNSS)测站速度是描述地壳运动的重要指标。本研究旨在通过高精度分析方法提升地壳运动监测的精度,基于日本地区两个GNSS测站(G178和J753)2016年至2023年东(East,E)、北(North,N)和高程(Up,U)方向的坐标时间序列数据,创新性地融合了极点模态分解(ESMD)与最小二乘拟合技术,以优化E、N和U方向上的速度估计。结果显示:基于本文提出方法估计的G178测站N、E、U三个方向站速度分别为-1.69、-1.58、4.60 mm/a,估计残差分别为0.03、0.02、0.04 mm/a。J753测站N、E、U三个方向站速度分别为-5.13、15.62、7.17 mm/a,估计残差分别为0.14、0.04、0.08 mm/a。本文提出的站速度估计方法较传统最小二乘法方法估计精度提高了19.81%~67.24%,站速度的拟合度提高了0.7%~2.1%。此研究证实,所提方法有效提高了GNSS测站速度估计的精度,对于地壳运动监测具有重要的科学价值和实际应用意义。 展开更多
关键词 极点对称模态分解(ESMD) 全球导航卫星系统(GNSS) 站速度 最小二乘拟合
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D对称矩阵反问题的最小二乘解 被引量:21
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作者 张忠志 胡锡炎 周富照 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2001年第5期6-10,共5页
研究了 D对称矩阵反问题的最小二乘解及其逼近问题 ,给出了最小二乘解的一般表达式 ,并就该问题的特殊情况 :逆特征值问题与矩阵反问题 ,获得了有解的充分必要条件 ,并在有解条件下得到了解的一般表达式 .
关键词 D对称矩阵 最小二乘解 最佳逼近 矩阵反问题 逆特征值问题 表达式
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基于对称方波调制的光纤陀螺本征频率自动测试方法 被引量:7
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作者 周友伟 刘铁根 +2 位作者 李茂春 侯丽丽 姚晓天 《激光与红外》 CAS CSCD 北大核心 2008年第7期676-679,共4页
从光纤陀螺的调制原理出发,采用频率为光纤环本征频率的1/2的对称方波对Y波导进行调制,分析光纤陀螺的输出信号,得到输出的方波信号的占空比与调制频率的对应关系,通过数据采集卡将占空比转化为方波上下峰值点数差的问题,并以此点数差... 从光纤陀螺的调制原理出发,采用频率为光纤环本征频率的1/2的对称方波对Y波导进行调制,分析光纤陀螺的输出信号,得到输出的方波信号的占空比与调制频率的对应关系,通过数据采集卡将占空比转化为方波上下峰值点数差的问题,并以此点数差作为反馈量调节对Y波导的调制频率实现对本征频率的自动锁定。该方法已在工程实践中得到应用,试验结果表明该测试方法可在几秒中之内完成而且测试精度可达0.01kHz。与已有的测量方法相比,基于对称方波调制的测试方法具有更高的精度、高速、数字化和易于实现自动测量。 展开更多
关键词 光纤陀螺 本征频率 对称方波调制 占空比
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一种软件锁相环和电压跌落检测新算法 被引量:29
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作者 陈国栋 朱淼 +3 位作者 蔡旭 李睿 宋晋峰 周悦 《中国电机工程学报》 EI CSCD 北大核心 2014年第25期4385-4394,共10页
动态电压恢复器(dynamic voltage restorer,DVR)的响应速度是衡量DVR特性的重要指标,锁相环和电压跌落检测算法则是决定其响应速度的2个关键因素,而电网电压畸变、跌落过程中发生的相位跳变和电压不平衡制约着锁相环和检测算法的快速性... 动态电压恢复器(dynamic voltage restorer,DVR)的响应速度是衡量DVR特性的重要指标,锁相环和电压跌落检测算法则是决定其响应速度的2个关键因素,而电网电压畸变、跌落过程中发生的相位跳变和电压不平衡制约着锁相环和检测算法的快速性。该文结合最小方差(least error squares,LES)滤波器和改进对称分量法设计了新的软件锁相环和电压跌落检测算法,对这2种方法进行详细的理论推导,阐明各频次的正负序分量解耦的机理。在Matlab/Simulink中搭建仿真模型,与传统锁相环方法和电压跌落检测算法进行对比分析。最后,在电压跌落平台进行工业样机验证,结果表明所提方法可行有效,且具有较高的响应速度。 展开更多
关键词 动态电压恢复器 最小方差滤波器 对称分量 软件锁相环 检测算法
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