To test the filter ' s effect , the half - wave fourier algorithm is used to calculate the amplitudes of harmonics . through the filter progress , the errors of results are reduced compared with that are before the filter . the errors are less than 10 % 为了验证滤波器的滤波效果,用半周傅氏算法对滤波前后的基波及各次谐波幅值的计算精度进行比较,滤波以后半周傅氏算法的精度有明显提高,计算误差在10 %以内。
This thesis performs the research how to analyze and design lithium niobate optical modulator in i - fog . the analysis concentrates on those performance parameters of a modulator : half - wave voltage , single mode performance , quasi te / tm polarization , loss , bandwidth and split - ratio 这些都是围绕调制器的性能参数来研究的,它们包括:半波电压,单模特性,偏振特性( te和tm模之间的输出功率比值) ,损耗,带宽及分支比等。
The relationships between extinction - ration , half - wave voltage and electrode structure have been analyzed with transfer matrix theory and effective index method . the following conclusions have been made : 1 ) . the electrode width can be optimized to get the lowest half - wave voltage of boa - type optical switch 我们设计的集总电极型boa光开关理论3db调制带宽大于2 . 5ghz ,半波电压为5v ,消光比大于40db ,对tm模的理论衰减大于45db ,而对te模的损耗小于0 . 15db 。
The bias magnetic field of the bias coil driven by bias current and small signal test current , results in the induced signal of the control coil . the terminal voltage of the control coil is detected by the test circuit . then the signal containing the information of rotor displacement is obtained , from which we can get the dc voltage signal proportional to the rotor displacement through half - wave rectification circuit and low pass circuit . this dc signal is put into a pid controller to get the control signal of the rotor displacement 偏置测试电路向偏置线圈输入偏置电流和小信号测试电流,两者产生的偏置磁场在控制线圈产生感应信号,检测电路检测控制线圈端电压并提取含有转子位移信息的电压信号,该信号经半波整流电路和低通滤波电路后得到与转子位移成正比例的直流信号,再由pid控制器转换为转子位移的控制信号,最后控制信号输入功放电路产生控制电流,实现闭环控制。
On the basis of the analysis and compare , we designed the least length of s - bend y - branch to decrease the transmission loss when the space between the outport is 250jjm . we also analyzed thoroughly dependence of half - wave voltage and bandwidth on the width , the length of modulator ' s electrodes and the gap between two electrodes 对于调制器的电极本文也进行较为深入的研究,探讨了电极宽度、电极长度、电极间距对半波电压的影响,并据此对单y相位调制器的电极结构进行了优化设计。
Second , we discuss the influence of environmental referance potential temperture and thermal wind on mesoscale symmetric instability . we find the expression of disturbance stream function and criterion of symmetric instability by analytical method and conclude that change caused by environmental referance potential temperture with height and thermal wind make critical richardson number and disturbance critical half - wave length of symmetric instability larger , that is to say , they benefit the occurance of symmetric instability . third , we study nonlinear perturbation analysis of mesoscale vertical circulation and evolution equation by means of f - plane . non - hydrostatic balance and filiter model 第二,讨论了环境位温与热成风因子对中尺度对称不稳定的影响。运用解析的方法求出了扰动流函数的表达式和对称不稳定的判据,发现环境参考位温随高度的变化与热成风因子使得对称不稳定临界理查逊数及扰动的临界半波长都变大,这有利于对称不稳定的发生。第三,采用f平面、非静力平衡、滤声波模式,讨论了中尺度垂直环流非线性摄动分析及演变方程。
The results of property test of dkdp crystal grown on a point seed show that laser damage threshold is about 5gw / cm2 , ? half - wave voltage is about 4kv , extinction ratio is about 1600 : l . the obvious difference of dkdp crystals is not found between traditional technique and point seed growth technique 性能测试结果表明,点状籽晶全方位生长的dkdp晶体的激光损伤阈值约为5gw cm ~ 2 、半波电压约为4kv 、动态消光比约为1600 : 1 ,发现与传统方法生长晶体的性能没有明显的差别。
According to our theoretic analysis and the realistic fabricating condition , the boa device with double - heterostructure gaas / gaalas has been proposed to obtain 3db bandwidth greater than 2 . 5 ghz , half - wave voltage about 5v , extinction - ration less than - 40db , transmission loss of tm mode greater than 45db and transmission of te mode less than 0 . 15db . to obtain higher switching speed , we proposed that traveling - wave electrode is applied to boa device 我们选择在sigaas衬底上生长重掺杂层,通过控制其厚度来设计速度匹配的boa光开关行波电极,实现boa光开关的高速和高带宽,本文结合boa型光开关的特点提出一种行波电极型boa光开关结构,其理论3db调制带宽大于20ghz 。