运载火箭天基遥测技术

针对我国天基测控技术的发展趋势,提出了基于S频段终端通过中继卫星进行运载火箭天基遥测,以某运载火箭发射GTO轨道任务为例,分别对天线跟踪特性和链路增益进行了分析计算,介绍了运载火箭天基遥测系统的组成,分析表明,在满足天线跟踪角和链路指标的条件下,可实现天基遥测;这些分析结论可为工程应用提供参考。     

基于FPGA的DDR3存储控制的设计与验证

DDR3SDRAM是第三代双倍数据传输速率同步动态随机存储器,DDR3具有高速率、低电压、低功耗等特点[1-2];在DDR3控制器的实际使用中,如何将用户需要存储的数据在DDR3中快速存储非常重要,如果数据被送到DDR3接口的速度低,则会影响DDR3的存储速度,同时影响DDR3的实际应用,因此,针对DDR3存储器设计存储控制有重要的意义[2];基于此设计主要分为低速读写控制与高速流读写控制,低速读写控制主要用于小数据量的操作,高速流读写控制主要用于批量数据的存储操作;此设计在FPGA上通过了大量数据读写的验证,证明数据存储的正确性;经过测试,在高速流读写模式下,DDR3存储控制设计的带宽利用率最大为66.4%;此设计在功能和性能上均符合系统总体设计的要求。     

W波段64通道相控阵微系统设计与实现

相控阵微系统的主要特征是电路与天线的高度融合集成,将三维微纳集成技术和微电子技术紧密地结合在一起,切合相控阵高频化、小型化和低成本的发展需求。本文设计了一款W波段的封装天线相控阵微系统,该相控阵采用硅基三维集成的方式将T/R多功能芯片、天线阵列集成在一个微系统模块中,并详细介绍了基于硅工艺的多功能收发芯片设计和相控阵封装天线设计。给出了相控阵微系统的测试结果。该微系统具有高集成度、高性能、低成本的特点,可以为高速无线通信、高精度探测和成像等应用提供一个较优的技术路径。     

Testing Transverse Sensitivity of Linear Single-Axis Pendulous Accelerometer with Double Turntable Centrifuge

Current ISO standard methods for testing transverse sensitivity of accelerometers are vibration-based. They have difficulties in producing low-frequency vibration for various reasons. This paper introduces a double turntable centrifuge (DTC) to test the accelerometer transverse sensitivity at low frequencies (from 0.01 to 10 Hz). The proposed method can avoid limitations of traditional vibration-based schemes for transverse sensitivity test. In this paper, a theoretical analysis of the method is followed by a presentation of the experimental set-up, and the measurement procedure of a linear single-axis pendulous accelerometer. According to the theoretical analysis and experimental results, it is practicable to test the low-frequency transverse sensitivity with a DTC. The method proposed here can test accelerometer transverse sensitivity at low-frequency with large amplitudes (up to 700 m/s²), and directly measure the angle of the transverse sensitivity with high resolution. It can be a supplement to the standard methods for testing accelerometer transverse sensitivity at low-frequency.     

模拟电路故障诊断的约束聚类集成BP网络算法

针对通用BP网络对于高纬度、大数据量训练收敛困难的问题,在使用动量因子、自适应调整学习速率等方法的基础,引入约束聚类,构造集成神经网络,以提高网络的训练速度及诊断效果;首先,采用约束聚类算法将训练样本集划分为若干个规模相当的子样本集,分别训练生成相应子网络;此外,在诊断过程中除各子网络的输出变量外,还加入了诊断数据相对各子训练样本集的隶属度因子;最后通过一个实际电路板25维采样数据、38类故障的BP网络诊断实例验证了算法的可行性。     

装备嵌入式信息中心系统研究与实现

装备嵌入式信息中心系统以未来信息化战争条件下装备的网络化保障的需求为背景,研究适应于未来战场的,能够提供装备一体化通信,状态监测、智能导航、故障诊断等功能的综合信息系统;该系统的研究突破了基于多传感器数据融合的状态监测技术、基于GPS和GIS的智能导航技术、多级故障诊断等多项关键技术;目前,信息中心系统已经在实验室环境下完成了小型一体化网络的构建工作,并在此基础上,完成了系统的功能和性能测试;试验结果表明,该系统已经具备进一步开展工程化研制和应用推广的水平和条件.     

基于PLC的地面能源远程控制方案

传统伺服地面能源系统的远程控制主要通过模拟量来实现,其自动化程度低、抗干扰能力差;为了解决以上问题,提出了一种基于PLC的地面能源远程控制方案,其分别采用了基于Profibus现场总线的分布式PLC控制技术、基于高压输出反馈的闭环控制技术、OPC Server与PLC远程通讯技术,实现了伺服地面能源系统的远程自动化控制功能,用基于虚拟仪器技术的人机交互界面取代模拟器件,用基于MODBUS协议的数字式网络传感器取代模拟传感器,实现了伺服地面能源系统数字化,提高了伺服地面能源系统的抗干扰能力。     

Preparation of LaNiO3/SrTiO3/LaNiO3 capacitor structure through sol–gel process

In this paper, SrTiO₃/LaNiO₃ (STO/LNO) bilayer films were prepared on lanthanum aluminate (LAO) substrates by use of the sol–gel technique. An array of LNO electrodes with diameters of 200 μm was prepared on the surface of STO/LNO bilayer films. Therefore, LaNiO₃/SrTiO₃/LaNiO₃ (LNO/STO/LNO), a capacitor structure with symmetrical top and bottom electrodes, was obtained. The XRD analysis showed that the obtained capacitor structure has a biaxial texture. The dielectric test suggested that the relative dielectric constant of the LNO/STO/LNO structure is symmetric, has a high tunability, and has a low dielectric dissipation factor (tan δ) in response to varying electric field bias. As the temperature decreased, the relative dielectric constant of the STO film increased, the tunability increased, and the tan δ decreased. At test conditions of 80 K and 100 kH, the tunability and the figure of merit (FOM) reached 56% and 107, respectively.     

Frequency dependent directivity of periodic permanent magnet electromagnetic acoustic transducers

Beam steering has been achieved using shear horizontal waves generated using a periodic permanent magnet (PPM) electromagnetic transducer (EMAT). Unlike phased arrays, where steering is achieved by carefully controlling the firing of individual elements, the spatial periodicity of the PPM EMAT is ultilised to steer the beam whilst exciting all elements simultaneously. Due to the periodic nature of the array, the interference of individual waves from each of the elements creates a highly frequency dependent angle of propagation, allowing the directivity to be changed by simply varying the frequency of the input signal. Simultaneous excitation precludes the need for complicated and expensive phased array hardware. A frequency domain model is developed so that the beam characteristics, such as steering angle and beam width, can be calculated, allowing for investigation into the beam steering qualities of the PPM transducer. Broadband pulsed generation is also demonstrated, showing how a wave is generated over a large range of angles, meaning a large area can be covered with a single pulse. Interesting properties of this wave, such as a variation of frequency as a function of angle, and how this can be useful, are also discussed.