Chaos synchronization of a chain network based on a sliding mode control

A sliding mode control approach is proposed to implement the synchronization of the chain tree network. The doublescroll circuit chaos systems are treated as nodes and the network is constructed with the state variable coupling. By selecting a switching sliding surface, the chaos synchronization of the network is achieved with one control input only. The stability analysis and the numerical simulations demonstrate that the complete synchronization in a chain network can be realized for all nodes.     

Analysis of frequency selective surface absorbers via a novel equivalent circuit method

An equivalent circuit (EC) method for absorbers design is proposed in this paper. Without using full-wave analysis, the EC method can predict the performance of the absorbers. This method is employed to synthesize broadband absorbers by inserting the resistors respectively into the single- and double-square loops structures, then two different prototypes with broadband absorbing frequency bands are manufactured and measured. By comparisons with the results both by using the full-wave analysis and by the measurements, the correctness of the new EC method is verified. Some factors which affect the absorbing bandwidth are also investigated. Due to its fast and accurate characteristics, the EC method which can be theoretically applied to arbitrary FSS is a good candidate for broadband design of the absorbers.     

Stability of operation versus temperature of a three-phase clock-driven chaotic circuit

We evaluate the influence of temperature on the behavior of a three-phase clock-driven metal–oxide–semiconductor （MOS） chaotic circuit. The chaotic circuit consists of two nonlinear functions, a level shifter, and three sample and hold blocks. It is necessary to analyze a CMOS-based chaotic circuit with respect to variation in temperature for stability because the circuit is sensitive to the behavior of the circuit design parameters. The temperature dependence of the proposed chaotic circuit is investigated via the simulation program with integrated circuit emphasis （SPICE） using 0.6-μm CMOS process technology with a 5-V power supply and a 20-kHz clock frequency. The simulation results demonstrate the effects of temperature on the chaotic dynamics of the proposed chaotic circuit. The time series, frequency spectra, bifurcation phenomena, and Lyapunov exponent results are provided.     

高速多光谱 TDI CCD 成像电路系统

为实现多光谱TDI CCD的高速高信噪比成像,利用可空间应用的多光谱TDI CCD传感器研制出了高性能成像电路系统。该系统以现场可编程门阵列（ FPGA）为核心逻辑单元,带有RS422外围通信控制接口,并采用CAMERALINK接口输出图像数据。系统具有动态推扫成像的能力,可同时输出全色和彩色两种模式的图像数据。利用灰度条纹的靶标对传感器的3个多光谱（ R、G、B）感光区标定白平衡,利用彩色条纹的靶标对系统进行成像测试,在驱动频率为15 MHz的情况下,系统单片CCD输出的图像数据率达到1.2 Gbps。试验结果表明,获取全色图像的信噪比达到了53.56 dB,各多光谱图像的信噪比较高的也在40 dB以上,满足空间对地高分辨多光谱遥感成像的技术指标要求,对高速空间多光谱遥感相机的研制具有借鉴意义。     

高重复频率脉冲激光能量测量（英文）

设计了一种用于高重复频率脉冲激光能量测量的峰值保持电路。电路由电荷积分器、2阶低通滤波器、时间延迟触发器和峰值保持器组成,通过将光电流脉冲转换成电压脉冲,电压脉冲的峰值与对应电流脉冲所包含的能量成正比。实验测量结果表明：该电路可以测量脉宽〈10 ns,重复频率≥2 kHz的重频窄脉冲激光的脉冲能量,且工作稳定,其线性动态范围≥140倍。该电路可应用于光电阵列探测系统中,能实现较高的空间分辨力。     

基于共面波导微带线的光探测器高频电参量提取

针对不能在片测量的光探测器芯片,本文提出了一个简单而有效的实验方案来提取其等效电路模型的高频电参量.首先设计了和微波探针匹配的共面波导微带线,测量其输出反射系数,测试结果与理论设计符合很好;然后将芯片装载到微带线上,测量包含光探测器的整个测试结构的输出反射系数.仿真中涉及光探测器测试结构的等效电路模型,包含光探测器、键合金丝和共面波导微带线等因素.通过拟合已测的整个测试结构的输出反射系数,提取了光探测器的高频电参量.     

基于DISLab瞬时速度连续性的测量研究

通过金属导轨将小车的位移转换为电压信号,电压信号经微分放大处理后用DISLab电压传感器采集数据并计算,可得到小车运动过程中的各个时刻的瞬时速度。     

Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells

Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (P_max) of silicon solar cells is presented and correlated using the displacement damage dose (D_d) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for P_max degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (V_oc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The “modified circuit” is capable of modeling the “radiation damage” in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.     

量子阱数变化对InGaN/GaN发光二极管瞬态响应的影响

理论上研究了当InGaN发光二极管(LED)有源区的量子阱数变化时,LED的大信号瞬态响应特性与这种变化的关系.结果来自于LED等效电路模型的SPICE模拟,模型参数的确定通过拟合已测量的LED的实验数据及模拟结果来实现.结果表明,LED光脉冲的上升时间随量子阱数的增加而增加,由3个量子阱构成的有源区是LED的优化结构.     

基于a-IGZO TFT的AMOLED像素电路稳定性的仿真研究

非晶铟镓锌氧化物薄膜晶体管(a-IGZO TFT)有望在有源矩阵有机发光显示(AMOLED)像素电路中得到实际应用,但其电压偏置效应仍会引起电路特性的不稳定。本文利用实验室制备的a-IGZO TFT器件进行参数提取并建立了SPICE仿真模型,通过拟合得到了它的阈值电压随时间变化的方程。在此基础上,采用SPICE软件对基于a-IGZO TFT的2T1C和3T1C两种AMOLED像素电路的稳定性进行了比较研究,证明3T1C电路对阈值电压偏移确实存在一定的补偿效果。最后讨论了进一步改善AMOLED像素电路稳定特性的方法和实际效果。