基于频域均衡的Tb/s级相干光单载波系统

对相干光单载波频域均衡系统(CO-SCFDE)、相干光单载波频分复用系统(CO-SCFDM)以及相干光正交频分复用系统(CO-OFDM)的理论和实验进行了对比研究,结果表明基于频域均衡的相干光单载波系统既保留了正交频分复用方式计算复杂度较低、频谱效率高和抗色散性能好的优点,又有效地减小了光纤非线性带来的传输损伤,是高速长距离光纤传输的一种有潜力的技术方案。     

利用FFT实现长码的直接捕获

在卫星导航系统中,普遍采用了长码扩频信号。长码扩频信号具有很强的抗干扰和保密能力,实现长码的快速直接捕获对于导航系统的军事应用和发展卫星定位系统具有重要意义。利用FFT计算可以使多次的时域伪码相位的循环相关处理转换为频域的一批乘法处理,单次计算即可获得一批相关结果,进而可加快长码的搜索和捕获速度。通过对多种基于FFT的方法进行比较,提出了适于工程应用的实现方式,并利用实际工作环境对设计进行了实际验证,结果表明该处理方法能够实现预期的目的,可以满足工程需要。     

Millimeter-Wave Power Amplifier Based on Coaxial-Waveguide Power-Combining Circuits

A millimeter-wave power amplifier based on a coaxial-waveguide power-combining circuit is presented in this paper. A coaxial stepped impedance transformer is used to provide an impedance transition from the 50- $Omega$ input coaxial line to the oversized coaxial waveguide, and its equivalent-circuit model has also been developed. A Ka-band four-device coaxial-waveguide power amplifier is fabricated and tested. The 10-dB return loss bandwidth of the fabricated amplifier is from 27.5 to 40 GHz, and the power amplifier has 17–25.9 dB gain over a wide bandwidth from 26 to 38 GHz. The measured output power at 1-dB gain compression is about 26.6 dBm at 30 GHz, with a power-combining efficiency of about 90%.      

330GHz砷化镓单片集成分谐波混频器

在太赫兹频段,二极管尺寸与波长相比已不能忽略,二极管的封装会引入很大的寄生参量,因此需建立二极管三维模型提取寄生参数.同时人工装配难度增大,会增加电路不确定性.采用12μm砷化镓单片集成悬置微带线结构,基于电子科技大学与中国电子科技集团第十三研究所自主联合设计的肖特基二极管研制330 GHz砷化镓单片集成分谐波混频器.实测结果显示在5 mW本振功率的驱动下,在328 GHz可得到最小变频损耗10.4 dB,在320~340 GHz范围内,单边带变频损耗小于14.7 dB.     

基于业务预测的同目的汇聚波带交换

提出了一种新的多粒度交换结构,在这种结构中,波带交换平面与波长交换平面相互独立,适合于采用同目的汇聚的波带疏导算法。为了提高波带业务疏导算法的效率,将业务预测技术引入疏导的计算。仿真结果表明,采用业务预测后,同目的汇聚业务疏导算法的阻塞率可以减少20％以上。     

闭环曲率补偿的低电源电压带隙基准源

A new low-voltage CMOS bandgap reference （BGR） that achieves high temperature stability is proposed. It feeds back the output voltage to the curvature compensation circuit that constitutes a closed loop circuit to cancel the logarithmic term of voltage VBE. Meanwhile a low voltage amplifier with the 0.5 μm low threshold technology is designed for the BGR. A high temperature stability BGR circuit is fabricated in the CSMC 0.5μm CMOS technology. The measured result shows that the BGR can operate down to 1 V, while the temperature coefficient and line regulation are only 9 ppm/℃ and 1.2 mV/V, respectively.     

Boosting the Charge Transport Property of Indeno[1,2‐b]fluorene‐6,12‐dione though Incorporation of Sulfur‐ or Nitrogen‐Linked Side Chains

Alkyl chains are basic units in the design of organic semiconductors for purposes of enhancing solubility, tuning electronic energy levels, and tailoring molecular packing. This work demonstrates that the carrier mobilities of indeno[1,2‐b ]fluorene‐6,12‐dione ( IFD )‐based semiconductors can be dramatically enhanced by the incorporation of sulfur‐ or nitrogen‐linked side chains. Three IFD derivatives possessing butyl, butylthio, and dibutylamino substituents are synthesized, and their organic field‐effect transistors (OFET) are fabricated and characterized. The IFD possessing butyl substituents exhibits a very poor charge transport property with mobility lower than 10^?7 cm² V^?1 s^?1. In contrast, the hole mobility is dramatically increased to 1.03 cm² V^?1 s^?1 by replacing the butyl units with dibutylamino groups ( DBA‐IFD ), while the butylthio‐modified IFD ( BT‐IFD ) derivative exhibits a high and balanced ambipolar charge transport property with the maximum hole and electron mobilities up to 0.71 and 0.65 cm² V^?1 s^?1, respectively. Moreover, the complementary metal–oxide–semiconductor‐like inverters incorporated with the ambipolar OFETs shows sharp inversions with a maximum gain value up to 173. This work reveals that modification of the aromatic core with heteroatom‐linked side chains, such as alkylthio or dialkylamino, can be an efficient strategy for the design of high‐performance organic semiconductors.     

商业银行信息系统研发风险模型研究

随着网络攻击方向的转变和攻击形式的层出不穷,应用系统安全问题日益凸显,而从研发过程着手提升信息系统安全性已逐渐成为业界共识.通过对当前主流的几种软件安全开发模型的对比与分析,总结软件安全开发模型的共有特点并结合商业银行信息系统风险特征,提出一种基于安全活动的商业银行信息系统安全研发模型,通过在信息系统研发全生命周期各阶段实施安全活动来提升其安全性,降低商业银行信息系统风险.     

激光光热辐射技术测量不透明复合材料的热扩散率

报道了一种用激光光热辐射技术测量不透明材料热扩散率的方法。根据红外探测器在不同频率下测得试样光热信号的振幅和相位 ,采用非线性拟合法 ,由振幅和相位分别对频率进行非线性拟合 ,由此可得材料的热扩散率 ,并对单向氧化铝纤维基复合材料进行了测量 ,给出了任一方向上的热扩散率的实验结果     

刀口法检测光学元件面形的数值模拟研究

传统刀口仪检测光学元件面形具有设备简单、非接触性测量等优点,但传统刀口仪只能定性评价面形质量,且人为因素较大。在传统刀口检测原理的基础上,建立了面形缺陷与阴影图相对应关系的数学模型。为了验证该模型的正确性,对口径150mm的凹透镜进行了数值模拟研究。设置模拟的缺陷参数,利用建立的数学模型得到对应的阴影图;用波像差理论对该阴影图进行分析处理,得到该元件的面形缺陷;将分析得到的缺陷参数与预先设置的面形缺陷进行比较,二者吻合很好。