查询词典 convergence frequency

Though comparing Canny operator and center B spline dyadic wavelet, the following conclusion is proven in this dissertation: a Center B spline function has tight support and Canny operator hasn't. b Center B spline function asymptotic convergence to Gaussian function and the derivative of Center B spline function asymptotic convergence to Canny operator. c The derivative of fourth order center spline B function is more suitable as a optimal edge detector than Canny operator. d Center B spline function can balance the smoothing and approximation of original data, and the fourth center B spline function is the only optimal solution of two order smoothing problem. e The error between the valve of time-frequency uncertainty of the fourth center B spline function and the lower bound of time-frequency uncertainty does not exceed 0.143% of the lower bound. f The derivative of center spline B function can construct a stability dyadic wavelet and can give a fast algorithm for multiscale edge detection, but Canny operator can do neither.

作者给出了Canny算子与中心B样条二进小波严格的比较证明，得出如下结论：a中心B样条函数具有紧支集，Canny算子不具有紧支集。b中心B样条函数的极限收敛于高斯函数，中心B样条函数的导数收敛于Canny算子。c四阶中心B样条函数的导数比Canny算子更接近最佳边缘检测滤波器。d中心B样条函数比高斯函数更能兼顾对原函数平滑和逼近的折中要求，并且四阶中心B样条函数是二阶逼近问题的唯一最优解。e四阶中心B样条函数的时频测不准关系值与时频测不准关系下界的逼近误差不超过0.143％。f中心B样条函数的导数可以构成稳定的二进小波，存在快速的多尺度算法；而Canny算子不构成稳定的二进小波，无法给出快速的多尺度算法。

Besides, as to inpainting problem in wavelet domain, we introduce a new iterative model. In this model low frequency and high frequency will carry on processing separately, enormous speed up the image repair convergence rate, and even if as high as 90% wavelet coefficient have been lost, this model will also be able to have the very good repair effect. In the old model, to compute the curvature we have to transform the coefficients to the pixel domain, and then transform back to the coefficient domain for several times and this method can solve this problem and speed up the iterative convergence.

其次针对小波域中图像修复的问题，本文提出了一种新的小波域图像修复模型，该模型根据小波变换后系数相关性的特点，将低频和高频分别进行处理，极大的加快了图像修复的收敛速度，并且即使丢失高达90%的小波系数，该模型也会有很好的修复效果，有效的解决了传统的TV- Wavelet模型在计算图像的平均曲率WCURV时，需要反复进行小波分解与重构的计算，迭代速度慢的问题。

to reduce the impact of carrier frequency offset in ofdm system,this thesis designs a new carrier frequency offset estimation scheme for ofdm system.the carrier frequency offset estimation includes acquisition and tracking.we adopt variable step size adaptive algorithm.the acquisition range of the proposed algorithm is as large as one half of the overall signal bandwidth.through this method we can not only avoid the feedback by using forward error correction,but also reduce the times of complex multiplication in order to reduce the power consumption of the system.this algorithm not only has low complexity and fast convergence nut also can improve the demodulation performance of ofdm system.computer simulation illustrates the superior performance of the proposed algorithm with regard to estimation accuracy in both awgn channel and multi—path channel.

摘 要：为了减小正交频分复用系统受频率偏差的影响，在ofdm系统中设计了一种新的载波频偏估计算法。频偏估计包括跟踪和捕获两个阶段，文中采用变步长自适应算法来进行跟踪，这个跟踪算法的捕捉范围是整个信号带宽的一半。通过此方法，不但可以利用前向纠错的方式来避免反馈，而且可以缩减复数乘法的次数以降低计算复杂度和系统功耗。该方法运算复杂度低，并具有较好的收敛性，能改善odfm的解调性能。从计算机的仿真效果可以看出无论是在awgn信道上还是在多径信道上都表现出了卓越的性能。

In order to overcome bad learning transients in ILC, the convergence condition in frequency domain is derived, and then the implementation method for monotonic decreasing learning transients is described with zero-phase filtering.

为了消除学习算法应用时出现的坏学习瞬态，这里先推导出所提控制算法在频域下的收敛条件，再给出基于零相位滤波的单调递减学习瞬态。

In the system of anti-active-interference, we introduce the FBLMS algorithm which can overcome the drawback of exacerbation of the convergence properties in the domain of time due to eigenvalue spread of input signal correlation matrix and improve the processing rate because of the parallel properties of the FBLMS algorithm. After discussing the properties of the FBLMS algorithm and its developed algorithm, the paper presents the result of computer simulation and proves the reasonableness and feasibility of canceling the active interference in frequency agility fuse.

在捷变频引信抗有源干扰系统中，引入了频域自适应滤波算法FBLMS，可以克服输入信号相关矩阵特征值分散所导致的时域横向滤波算法收敛特性恶化的缺点，并且，由于算法的并行处理特性，大大提高了算法的实时处理性能，本文在分析了频域FBLMS算法的性能和改进算法后，给出了计算机模拟仿真结果，验证了对捷变频引信有源干扰抑制的合理性和可行性。

After analyzing the limitation of slow convergence in adaptive Least Mean Square algorithm, it is brought forward the method of transforming signal into frequency domain, taking advantage of the orthogonality of discrete Fourier transform, the adaptive LMS filter is performed for each frequency element in transform domain.

四川大学博士学位论文在频域自适应滤波的基础上，提出了一种权值反馈方法抑制图像传输中的多个大功率平稳强窄带干扰信号，不仅能加快算法的收敛性能，并具有良好的滤波效果。

The Pade approximation is combined with 3-D frequency-domain finite difference (3D-FDFD) for the first time. The impact of expansion point and the order of rational function on the accuracy and the convergence radius is discussed in this dissertation.

主要包括以下内容：首次将Pade逼近运用到三维频域有限差分法中，详细讨论了Pade逼近中展开点选取、收敛半径与有理阶数的关系问题。

Due to the particular space convergence and wide flow of its productive components, public crisis is featured by high frequency, large scale and indefiniteness.

因此，如何寻求科学合理高效的公共危机管理模式就成为当今城市政府迫切需要解决的重大课题，是城市社会可持续发展的重要环节。

Also, this dissertation established a sufficient condition for ILC convergence of a class of uncertain nonlinear time varying systems with a discussion on the convergence speed. Furthermore, for a class of linear systems, frequency-domain convergence analysis has been provided for a closed-loop type ILC algorithm with a convergence speed comparison with the conventional Arimoto-type open-loop ILC algorithm.

同时还给出了存在不确定及干扰非线性时变系统迭代学习控制收敛的充分条件，并对闭环迭代学习控制收敛条件和收敛速度进行了频域分析和讨论。

Frequency offset, convergence time, phase noise and hardware cost are the most important factors for algorithm selecting. First, the carrier recovery loop is divided into two parts, frequency recovery loop and phase recovery loop.

由于载波恢复需要捕获较大的频偏范围、较短的收敛时间、较小的相位噪声和较低的硬件实现成本，所以本文从这四个方面考虑算法的选择。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。