信号传输法

This model can provide the good base of adaptive modulation and coding and automatic repeat request as well as dynamic resource allocation.

首先分析了正交频分复用技术频域信道统计特性，说明了Nakagami-m分布能更好地描述衰落信道；然后针对高速移动及OFDM信号传输的特点，采用状态持续时间相等法建立了OFDM频域信道有限状态马尔可夫模型，分别给出了计算持续时间、状态门限及状态数、转移概率、状态差错率的一般方法及m=0.5\1\2典型值的闭式解，该模型能为自适应模型控制、混合自动重传请求 HARQ、动态资源分配等技术提供良好的基础。

Researched influence of frequency on characteristic of electromagnetic wave transmission in tunnels, and analyzed characteristic of electromagnetic wave transmission in circular, arches and curved tunnels by method of metal wave guide, and gives approximate formulas of attenuation rate. Main conclusions we obtain are as follows: in circular,rches tunnels, if frequency is higher, attenuation rate is smaller, it is beneficial for EM waves to transmit, in curved tunnel, higher frequency, more attenuation rate ...

研究了频率对井下电磁波传输特性的影响，采用金属波导法分析了圆形、拱形及弯曲隧道中电磁波的传输特性并给出衰减率近似公式，得出主要结论：在圆形和拱形隧道中，频率越高，衰减率越小，越有利于电磁波的传播；在弯曲隧道中，频率越高，衰减率越大，不利于电磁波的传播；通过特性曲线与井下实验数据相比较得出在900MHz左右为井下无线通信系统传输信号最佳频段。

The dissertation presents a number of methods and theory involving in diffraction integral, Fourier transform, directly solving differential wave equation, vector analysis, which can be used to study ultrashort pulsed beams propagating in free space, linear dispersive

现将本论文所得主要结论总结如下：基于瑞利—索末菲衍射积分、角谱法和复解析信号法，推导出了等束腰宽度超短脉冲高斯光束在自由空间的严格的传输方程和傅里叶谱，适用于几个光周期甚至一个光周期以下的超短脉冲光束和大衍射角情形，而不产生空间奇异

Based on the Rayleigh-Sommerfeld diffraction integral and complex analytical signal representation,the free-space propagation equation and its Fourier spectrum for ultrashort chirped pulsed Gaussian beams are derived,and the far-field analytical electric field and spatial intensity are presented.

基于瑞利-索末菲衍射积分，使用复解析信号法推导出了啁啾脉冲高斯光束在自由空间中的传输方程及其傅里叶谱，给出了远场的光场和空间光强的解析式，研究了啁啾参数C对脉冲光束传输的影响。

A new generating circuit on five-level M-sequence based on the cut-join sieve method,which can generate 2048 different five-level M-sequence s.

敌我识别系统的核心技术之一是询问信号与应答信号的加密传输，针对信号传输中对密码的要求，文中引入了伪随机码，基于剪接筛法设计了能产生2048个两两相异的5级 M序列的电路，并对该电路进行了仿真，仿真结果验证了该设计的正确有效性

A large mode area core erbium doped K9-glass single-mode photonic crystal fiber is designed by getting the pump and signal intensity profiles from plane wave expansion methodand solving propagation-rate equations.Its diameter is 20μm,limit ellipticity error is 94.7%,and limit offset of inner ventage is 0.1μm.Then we analyze its amplifier characteristics.

根据平面波展开法给出泵浦光和信号光本征模场分布，结合速率方程和功率传输方程设计一种大单模尺寸的实芯掺铒K9玻璃大模式面积单模光子晶体光纤，芯径为20μm；分析其椭圆度容差为94.7%，最内层小孔最大允许偏移量为0.1μm；分析了掺铒K9玻璃光子晶体光纤放大器的放大特性。

The phase tracking principle of source-contained homodyne detection is researched, the frame diagram for phase detection and experimental results are given.

介绍了一种新型的光纤电压传感器结构和工作原理，分析了系统中椭圆芯双模光纤的传输模式和模间相干光斑的变化，采用熔接的方式进行相干光接收来获得正交相位漂移信号，根据模间群折射率差与光程差的关系设计调整光纤的长度，依据石英晶体和空气的绝缘强度进行传感光纤匝数设计，讨论了含源零差探测法的相位跟踪原理，给出了相位检测框架图及实验结果，分析表明该设计方案能达到相位跟踪的目的。

As a general rule, no more that 15 consecutive zeros can be transmitted without violating the ones density rule. B8ZS (Binary 8 with Zero Substitution), the newer line coding technique used in T-1 circuits, substitutes alternating bipolar pulses for the eighth zero in a string of eight consecutive zeros. B8ZS also supports clear channel communications of 64 Kbps per channel.

作为一种通用规则，不存在连续15个以上0序列被发送而又没有违反信号密度规则。T-1电路中使用的最新的线路编码技术B8ZS（二进制八0替换法）在信号传输中出现连续8个0时，将使用交替双极脉冲替换这8个0.B8ZS也支持64kbps信道的纯信道传输。

Based on coupled-mode theory and transfer matrix, numerical results show that about 1 m of such thin-clad chirped LPFG can compensate 46 km fiber's dispersion.

利用耦合模理论及传输矩阵法计算了约1 m长的此种啁啾LPFG的色散，结果表明可以补偿该光信号通过46 km光纤所产生的色散。

Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.

最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势，并设计了一款彩色夜视摄像机。

Only person height weeds and the fierce looks stone idles were there.

只有半人深的荒草和龇牙咧嘴的神像。