基于法布里-珀罗激光器的超高重复频率光脉冲生成技术

本文提出了一种新的基于双模自注入锁定DC电流驱动的法布里-珀罗半导体激光器(FP-LD)来生成超高重复频率,高功率光脉冲的简单方法。传统的基于注入锁定增益开关调制的FP-LD产生光脉冲方法,存在输出脉冲重复率低(通常小于10GHz)、啁啾大和低输出功率的缺点。文章提出的方案中,通过一个带直流偏置的FP-LD与两个均匀光纤布拉格光栅(FBG)相连,来实现双模自注入锁定输出。该输出信号再进入一根长的、高度非线性的光纤(HNLF)中,通过自相位调制和反常色散之间的相互作用可获得高频光脉冲。实验结果,在FP-LD相邻的两个纵模同时注入锁定时,可获得了重复频率为139.6GHz宽度为1.6ps和时间带宽积为0.34的孤子光脉冲,峰值功率为120mW。我们还观察到当改变光栅的应力,可选择相间隔的两个纵模同时注入锁定,重复频率为279.2GHz的光脉冲序列,由于该脉冲序列的四波混频增益较139.6GHz序列低,因此四波混频效应不明显。该方案结构简单,成本低廉。     

组合式电子互感器的理论和实验研究

基于反射式偏振干涉原理和模间干涉原理，研制出一种新型的可同时测量母线上的电流和电压的组合式互感器。这种互感器绝缘结构简单，电压测量与电流测量间无相互干扰，为消除外界干扰、提高系统的测量精度提供了理论根据。     

基于双模接口的测试系统设计

为了对飞行设备进行各种性能参数的测试,同时避免因环境因素而带来的数据传输不稳定的问题,使用双模接口(以太网接口与USB接口)实现上位机与测试系统的通信,通过对采样电路进行优化产生多路高精度信号并实时监测接收返回的群信号;经实验证明,系统完全可以完成一般环境中的功能测试,并提高了系统测试精度与传输数据的可靠性。     

一种适用于GSM/WCDMA的高线性度滤波器及带有消除直流偏置的可变增益放大器

采用SMIC 0.35μm CMOS混合信号工艺,实现了同时适用于GSM/WCDMA的完整的基带.基带由双模的高线性度的四阶切比雪夫形式的有源RC低通滤波器以及三级可变增益放大器构成.滤波器的设计同时满足GSM和WCDMA的带宽性能并且为降低制造成本在两种模式下具有最大的元件共享度.基带由于插入了高通滤波器具有滤除直流的功能,并且为了优化GSM模式下的功耗,运放的带宽做成可调.在最大增益情况下测得的噪声系数在GSM和WCDMA模式下分别为42和27.3dBm.在单位增益的情况下,WCDMA模式下的IIP3为40dBm,功耗为47.0mW;在GSM模式下,IIP3为28dBm,功耗为31.8mW.电源电压为3.3V.     

High-temperature superconducting dual-mode resonator on (100) MgO substrate

We report, for the first time to our knowledge, a clear resonant peak split in the range of 7.7–9.7 GHz in a perturbed dual-mode disk-type resonator (DMDR) made of YBa₂Cu₃O_7–x (YBCO) superconducting thin film on MgO substrate. Epitaxial YBCO superconducting thin films were grown on (100) MgO substrates by pulsed laser deposition technique. The critical temperature of superconducting thin film on MgO substrate was 85 K. Superconducting dualmode disk resonators were designed by microwave design software, EEsof, and patterned by photolithography and a wet-etch process. The unloaded quality factor (Q_UL) of the superconducting DMDR was found to be 1,312 at 77 K. We believe this type of DMDR can be utilized for dual-mode resonator-based filters for satellite communications.     

TD-LTE/FDD LTE融合浅析

文章从LTE网络发展现状出发,预测了LTE发展趋势,并分析了双模LTE基站的可行性,为运营商LTE网络建设提供了一种新的思路。     

Two-level energy management strategy for PV-Fuel cell-battery-based DC microgrid

With the fast development of DC Microgrid (MG) technology, its operating economy and reliability are getting more and more concern. The traditional distributed control method is aimed at power balance and system stability, and is difficult to meet the requirement of energy management system for multi-source hybrid DC MG. This paper provides a two-level energy management strategy for PV-fuel cell-battery-based DC MG, which is divided into device control level and system control level. At the device control level, the distributed control methods based on MPPT-droop dual-mode control and droop control are proposed to enhance system reliability; at the system control level, the equivalent consumption minimization strategy (ECMS) is used to distribute system net power between battery pack and fuel cell system. A lab-scale DC microgrid platform is developed to verify the proposed energy management strategy in this paper. Moreover, the analysis and compare of the results show that the proposed two-level energy management strategy can achieve lower equivalent hydrogen consumption than classical PI control and state machine control method.     

基于区域划分的双模式盲均衡算法研究

改进常模算法(MCMA)克服了常模算法(CMA)对相位不敏感的缺点,但收敛性能仍然较差。本文研究了依据区域划分将MCMA和判决引导(DD)算法有机结合的双模式盲均衡算法:通过综合考虑信噪比和剩余码间干扰,研究了区域划分边界的确定;讨论了不同模式中步长的选取;并应用滞后切换策略克服这种算法中的稳态误差波动问题。仿真表明:此算法收敛速度快、稳态误差小,并能在去除码间干扰的同时纠正信道固有的相位旋转和一定范围的载波频率偏移,具有很好的实用性。     

Superconducting Planar Filters Using Dual-Mode Cross-Slotted Square Resonators

Passive microwave filters based on high temperature superconducting (HTS) films are very promising for telecommunication applications. Filters based on a dual-mode configuration present the appealing combination of high power handling capability and excellent miniaturization. Here a new kind of dual-mode filter based on cross-slotted square resonators is presented. The novelty of this structure is related to the use of a pair of unequal crossed slots formed on a square patch resonator, so that the size of the device can be significantly reduced. Single stage dual-mode filters are designed with a commercial 2.5D software at frequencies of interest for satellite communications. Prototypes based on a square resonator with 6 mm side operating at 3.7 GHz are fabricated using Nb double-sided films grown on 10 × 10 × 0.5 mm³ LaAlO₃ substrates. The response is measured at 4.2 K and the nonlinearity is investigated observing the power degradation. The effect of additional cuts, opportunely realized on the conductor surface, is discussed in respect to the size reduction and the maximum circulating power. It is found that the resonant frequency can be reduced from 3.7 to 3.3 GHz without affecting the power handling capability.     

煤矿斜井双模式盾构刀盘的受力特性研究

刀盘是盾构机的关键部件,为保证煤矿斜井双模式盾构的顺利行进,需对刀盘的强度和刚度进行研究.以新街煤矿斜井工程为例,分析双模式盾构刀盘不同模式时在多工况下的受力特性,给出了刀盘载荷计算方法和公式,基于双模式盾构的刀盘结构特点建立简化模型,采用ANSYS软件分析,得出了双模式盾构刀盘不同模式时在多工况下的应力应变分布规律.研究结果表明:最大变形出现在土压平衡盾构(earth pressure balance,EPB)模式偏载堵转工况中,其值为3.821mm,最大应力出现在硬岩隧道掘进(tunnel boring machine,TBM)模式偏载堵转工况中,其值为284 MPa,多种工况最大应力值出现位置均位于牛腿与法兰盘连接处或牛腿与刀盘连接处.根据研究结果可知新街煤矿斜井双模式盾构刀盘设计合理,并针对应力集中部位提出了优化建议.