Given the multicast request , the optimal object of the problem is to minimize total number of conversions required . in wavelength assignment , we should consider the requirements that the number of needed converters along the path from multicast source node to any member cannot be larger than specified value because of the signal distortion introduced by wavelength converters . at last , we present several dynamic programming to get the exact optimal wavelength assignment scheme under session blocking policy and destination blocking policy 考虑到波长转换器引入的信号失真和噪声，引进了失真约束，即要求从组播源结点到每个组播成员的路径上使用的波长转换器数目均在指定的范围之内;对于给定的组播需求，优化目标是在满足失真约束的基础上使整个组播树上使用波长转换器的数目最少;并使用动态规划给出了sbp和dbp两种连接建立策略下精确的最优波长分配算法。
Computer simulation results show that the proposed algorithm reduces the signal distortion and the reverberation which are caused by misadjustment errors in the adaptive filter and the correlated component of the speech in the reference signal compared with a conventional adaptive noise canceller ( anc ) 仿真结果证明nanc算法有效克服了影响传统自适应噪声抵消系统( anc )性能的一些瓶颈，如两输入中的非相关噪声，参考输入中的信号成分与自适应滤波器失调误差而产生的信号失真、回响等情况。
It also studies the influencing factors including sampling frequency , pd waveform , decline time , time intervals between pd pulses , mother wavelet , center frequency of interference , entropy threshold value and snr . in addition , it applies wavelet packet method （ wpm ） for non - stationary signal de - noising in on - line pd monitoring and analyzes the processing results under different pd waveform , sampling frequency and noise level . firstly , the curve of pd 基于小波包变换的非平稳信号消噪算法（ wpm ）已较为成熟，本文将其应用于局部放电在线监测，通过研究其对不同局放波形、采样率、噪声水平下的处理效果，首次提出了理想白噪声条件下提取局部放电信号的曲线，分析了各种因素对该算法下信号失真的影响。
Mems device has advantages as below : 1 , low insertion loss , and high q parameter ; 2 , low power consumption and high efficiency ; 3 , good linearity compared with semiconductor device and low signal distortion . recent years , mems production technology has developed maturely and gives a fine solution for low - cost , small - sized and higher frequency application in wireless communication Mems器件具有以下优点: 1 , mems器件具有很小的插入损耗,这样可以得到更高的品质印数; 2 ,动作时需要极小的功率,因此效率很高; 3 ,与半导体器件相比, mems器件具有很好的线性,因此信号失真很小。
Hence analysis and design of nonlinear sampled - data systems has been , in recent years , a subject of growing interest in the international community of control research . when a continuous - time plant is controlled using a digitally implemented controller , it is often faced that a continuous - time plant is transformed into its equivalent discrete - time model . a digital controller is usually designed on the base of approximate discrete - time models of the continuous - time nonlinear systems because it is difficult to obtain the closed form of the exact discrete - time model for nonlinear control systems 利用计算机等一类离散控制装置来控制连续时间的受控对象时，都会遇到把连续时间系统化为等价的离散时间系统的问题，通过采样器和保持器来实现离散时间的采样控制，对于非线性连续受控系统，由于连续系统的时间离散化后一般得不到其等价的精确离散化模型表示的有限形式，实际上由其近似离散化模型代替来设计控制器，而近似会引起信号失真，那么基于近似离散化模型上设计的采样控制器，它是否同样对原连续受控系统有效
That extremely promotes the development of the receiver . also the requirement of receiver becomes more rigorous . as the name implies , receiver need to improve the linearity , to reduce the distortions rate and bit error rate , and to expend the dynamic range , of course should ensure the signal detect capability precondition 这些要求同样也促进了中频接收机的不断进步,要求其在保证信号检测能力(即极高的灵敏度)的前提下:尽可能的提高接收机的线性度,使信号失真最小、误码率最低;尽可能的展宽接收机的动态范围,使接收机的适应度更大、抗干扰能力更强。
