And the fractionally spaced equalizers ( fse ' s ) are also presented in this thesis through comparing the performances of fse ' s and the common baud spaced equalizers . the computer simulations show that the fse ' s are especially suitable to the underwater acoustic channel with low snrs 文章通过计算机仿真,对比了分数间隔均衡器和普通的波特间隔均衡器的性能特点,并且发现当水声信道噪声较强时,特别适合于采用分数间隔均衡器。
Abstract : the sources and categories of noise about return - path of hfc ( hybrid fiber / coax ) are analyzed , and a few effective methods of reducing noise are presented for different noise , which simultaneously the choice of modulation and multiple access technology is adopted to reduce the noise 文摘:分析了hfc网络上行信道噪声的来源和分类,针对不同的噪声提出几种有效的抑制方法,同时结合上行信道多址接入方式和调制解调方式的选择来抑制噪声。
The signal processing can ensure and improve the performance of plc , the main methods include filter , data coding , error correction , etc . firstly , the characteristic of power line channel is discussed from the transmission lines , noise , and channel attenuation in this paper 信号处理研究是为了保证电力线通信质量、提高其性能,主要的方法如数据编/解码、纠错、抗干扰处理等。本文首先从传输线特性、信道噪声和信道衰减三方面分析了室内电力线信道的特点,并提出一种适合室内近距离的电力线载波通信方案。
Conventional detector ( single - user matched filter ) distinguishes each user by the crosscorrelation of their spread - spectrum codes . in practice , however , its performance is much deteriorated due to the existence of noise in channel and strong multi - access interference , i . e . near for effect . a new method using independent component analysis is proposed in this paper . the - received energy of signals is controlled effectively , thus the near - far effect is overcome as much as possible ; moreover , the effect that noise imposed on the detector is mostly reduced . simulations verify the effectiveness of this method 传统检测器(单用户匹配滤波)利用扩频码之间的互相关特性来区分各用户信号.而在实际应用中,信道噪声和近距离用户对远距离用户的强多址干扰即远近效应,使得接收机的性能受到很大影响.本文将独立分量分析法引入传统接收机,有效控制接收信号的能量,从而极大地提高了接收机的抗远近性能,同时噪声的影响被尽可能消除.仿真结果表明了该方法的有效性和可行性
Future wireless applications , such as video cellular telephony , wireless internet access and wireless lans , have open a new field for wireless multimedia communication - image communication , which push a growing demand for fast , economic , low - energy mobile multimedia communication . however , there are still several bottlenecks - bandwidth , low - delay , power and noise etc , need to be solved 然而由于无线视频通信存在许多瓶颈与协议问题:包括带宽要求、实时性要求、功率限制和信道噪声等,面向无线的视频编码与传输技术已成为当今信息科学与技术的前沿课题。
After the system has been synchronized , we first use the least square method to make channel estimation , then separate the channel response information from the channel noises by dft . a weighting function based on the minimum mean square error ( mmse ) criteria can be applied to the time domain channel impulse response 在系统同步条件下,首先使用最小平方方法来估计信道响应,然后利用离散傅利叶变换的性质把信道响应信息和信道噪声分离,并在时域按最小均方误差准则做加权处理。
Abstract : in this paper , we study the synchronization approach for hyperchaos system of 4th - order cellular neural network analyze its pefforraance in the presence of parameter mismatch and channel noise , and propose a design method for a spread - spectrum secure communication system based on hyperchaos of cellular neural network 文摘:研究了四阶细胞神经网络超混沌系统同步方法,分析了系统存在参数失配和信道噪声时的同步性能,提出了一种基于细胞神经网络超混沌同步系统的扩展频谱保密通信设计方法。
The characteristic of channel is the basic of plc research , including the transmission lines , channel noise , and attenuation . the ability of anti - jamming , speed and distance of transmission are decided by the mode of modulation . for example , the fsk , bpsk , cdma and ofdm are main modulations in the plc 信道的研究是根本,电力线通信其他研究内容都是建立在信道研究的基础上,内容主要包括传输线特性、信道噪声和信道衰减等;调制解调技术决定了电力线通信的传输速率、传输距离和抗干扰能力,它是电力线通信实现的关键,目前电力线通信中主要的调制方式有fsk 、 bpsk 、 cdma 、 ofdm等。
Also the computation complexity is rather low . thirdly , we proposed two algorithms for 3d mesh models compression using vector quantization : one scheme is based on an extended codebook , with which the correlations between indices of adjacent vertices are adopted and 基于目前大多数可逆水印算法针对原始域媒体的不足,结合矢量量化的思想,提出了一种压缩域三维网格可逆数字水印算法:该算法通过改变矢量量化压缩过程的矢量预测方式来嵌入水印信息,使水印对于信道噪声引起的