The tapped delay model of the multi - path frequency selective fading channels as well as the diversity receiver technique is introduced , and the principles of rake receiver are described . then various downlink channel estimation techniques , such as simple averaging , wmsa and fbprelms are analysed in detail 本文首先讨论了移动通信信道的各种参数对信道估计的影响,介绍了频率选择性信道的抽头延迟线模型和分集接收技术,在此基础上阐述了rake接收机的原理。
The proposed algorithm lows the complexity by choosing decision delay in advance and then making solution of the equalizer tap coefficient , a new decision delay choice method is proposed , solution by using weight method , diagonal matrix transform , z extension and a new energy restrictive condition which restrains noise enhance , a new decision delay choice method is proposed , the simulation result shows that the proposed algorithm has better equalization effect and enhanced performance comparing to the general mmse algorithm , simulation research on the precision and dynamic scope of parameters in digital realization time domain equalization algorithm , design software and hardware of time domain equalizer . fourthly , there exist a lot of interfere in dsl line , especially , dsl works in multi - user mode , the near end interference is serious 通过先选择判决时延，再进行时域均衡器抽头系数求解的方法降低了时域均衡计算复杂度；对于均衡器抽头系数的求解使用了加权技术，通过对角矩阵变换， z扩展，使用不同的能量约束条件对算法求解，结果表明这种约束有效的抑制了噪声增强，与常用删se比较，该算法有更佳的均衡效果，算法性能得到了提高：论文还对数字化实现时域均衡算法中每一部分参数的精度、变量的动态范围进行了模拟研究，对时域均衡的软硬件实现进行了设计。
In the second chapter , a wideband mimo channel model with multiple - tap was integrated according to the angle of departure of the transmitting signal and its spread angle , the angle of arrival of the receiving signal and its spread angle , power azimuth spectra , doppler spectrum and the geometric construction of antenna array both sides of transmit and receive , on the basis of full research on the theories of space - time channel model proposed in the recent literature 第二章在对最近文献中提出的一些空时信道模型理论进行详细研究的基础上，根据发射信号的离开角及其扩展角、接收信号的到达角及其扩展角、功率方位谱、多普勒谱和收发两端天线的拓扑结构，综合了一个多抽头的宽带mimo信道模型。
Although adsl comes with new digital processing , coding , modulation and error correction technologies , it is also faced with various challenges out of subscriber lines , such as background noise , impulse noise , insertion loss , cross talk , wire size variations , bridge tap , line joints and line insulation , etc . all those factors tend to produce adverse impacts on the performance of high - speed transmission services . firstly , the insertion loss of copper lines increases in proportion to the length of lines 虽然adsl采用先进的数字信号处理技术、编码调制技术和纠错技术，但是在推广adsl业务时，用户线路的许多特性，包括线路上的背景噪声、脉冲噪声、线路的插入损耗、线路间的串扰、线径的变化、线路的桥接抽头、线路接头和线路绝缘等因素将影响高速率传输业务的性能。
The tapped line input output block with compact structures and flexible design method , was studied by many designers in the sixties and seventies of last century . but it is because the weak precision , hard tuning and long design period of traditional equivalent circuit method influences the development and wide use of this block 抽头式输入输出单元,以其紧凑的结构形式,灵活的设计方法,早在上世纪六七十年代就被许多人员研究,但是由于等效电路法分析该单元的精度较差、调试难度大、研制周期长等原因,影响了抽头式微波滤波器的广泛应用。
The device is a synthetical applicating example of phase modulator , intensity modulator and directional coupler theory . the characters and fabricating process of linbo _ 3 optical waveguide , electrodes design principle , the influence of sio _ 2 dielectric buffer layer on the performance of the device and design principle of tapped power ( ratio ) are analyzed 该器件是相位调制、强度调制和定向耦合器理论综合应用的典型,文章从理论上分析了linbo _ 3光波导的特点、制作工艺、电极设计原理、 sio _ 2介质缓冲层对器件性能的影响和抽头功率的设计原理等。
Through analyzing the mathematical model of two winding transformer , the effect after on - load tap changing on voltage and reactive power balance at each side , effect of shunt capacitor compensation on voltage and reactive power balance in substation the relation between transformer tap adjusting and shunt capacitor switching in practical grid operation were discussed 摘要通过对两卷变压器的数学模型进行分析，讨论了两卷变压器抽头调整后，变电站各侧电压及无功功率的变化；无功补偿对变电站各侧电压及无功功率的影响；实际电网生产运行中，无功补偿与变压器抽头的配合调整。
