一种基于熵源分离模型的可重构安全原语

在信息爆炸时代,信息的安全问题受到了广泛关注。在物联网设备的加密协议中,物理不可克隆函数(PUF)与真随机数发生器成为加密协议中基本的安全原语,提供了轻量级的解决方案。文章提出了一种熵源分离模型,能够分离环形振荡器中抖动(真随机数发生器的熵)和工艺偏差(PUF熵)引起的延时。基于该模型,在FPGA上设计了一种可重构的双工作模式电路,通过改变模式可分别生成PUF和真随机数。相较于FPGA上独立设计的PUF和真随机数发生器,该结构具有资源开销小、面积利用率高、功耗低等优势。实验结果表明,生成的PUF稳定性高、唯一性强、均匀性好;真随机数序列均通过了NIST测试,具有高随机性和不可预测性。     

一种应用于HDMI接收端的宽频带锁相环设计

基于110 nm CMOS工艺设计了一种应用于HDMI接收端电路的宽频带低抖动锁相环。采用一种改进型双环结构电荷泵,在25～250 MHz的宽输入频率范围内实现了快速锁定。通过高相噪性能的伪差分环形振荡器产生了调谐范围为125 MHz～1.25 GHz的时钟信号。仿真实验结果表明,该锁相环的锁定时间小于1.2μs,在振荡器工作频率为0.8 GHz时,其相位噪声为-100.0 dBc/Hz@1 MHz,输出时钟峰峰值抖动为4.49 ps。     

基于高速环形振荡器的皮秒量级事件计时测量

研究设计基于高速环形振荡器的皮秒量级事件计时器。利用代表事件的信号上升沿去触发高速环形振荡器,产生与事件同步的时钟脉冲信号,对正弦参考信号采样,再通过全相位FFT算法处理,大幅提高事件计时测量的精度。实验结果表明,在正弦参考信号中心频率f₀=10 MHz,全相位FFT运算点数N=8 192,ADC的量化位数b=14 bits,采样频率f_s=140 MHz的情况下,事件计时器能够获得约3.16 ps rms的单次测量精度,时间稳定性优于±0.31 ps/h,实验结果与基于理论分析的误差范围一致,达到皮秒量级事件计时测量。     

面向逆变器并联的虚拟振荡器控制技术综述

虚拟振荡器控制作为继下垂控制和虚拟同步机控制之后提出的新型多逆变器无互联线并联技术,因其独特的自同步机制和快速的动态响应性能等特点而成为当前的研究热点。从控制结构、多机同步运行机制和动力学特性方面论述了虚拟振荡器的控制原理;从功率控制策略、小信号稳定性、新型虚拟振荡器方案3个方面对虚拟振荡器控制技术的研究现状进行了全面综述;分析并总结了虚拟振荡器控制与下垂控制、虚拟同步机控制的对比研究。结合目前虚拟振荡器控制面临的若干关键问题,对未来研究方向和可能的相关解决思路进行了探讨。     

用于超外差接收机提供本振源的高功率510 GHz单片集成三倍频器

本文介绍了一种基于砷化镓材料的高功率490~530 GHz单片集成三倍频器。基于提出的对称平衡结构,该三倍频器不仅可以实现良好的振幅和相位平衡,用来实现高效的功率合成,还可以在没有任何旁路电容的情况下提供直流偏置路径以保证高效倍频效率。同时,开展容差性仿真分析二极管关键电气参数与结构参数对倍频性能的影响研究,以便最大化提升倍频性能。最终,在大约80~200 mW的输入功率驱动下,研制的510 GHz三倍频,在490~530 GHz频率范围内,输出功率为4~16 mW,其中峰值倍频效率11%。在522 GHz频点处,该三倍频在218 mW的输入功率驱动下,产生16 mW的最大输出功率。该三倍频器后期将用于1 THz的固态外超外差混频器的本振源。     

无耦合PCNN频域特性分析

脉冲耦合神经网络（PCNN）模型具有脉冲调制和耦合连接特性,广泛应用于数字图像处理领域。然而现有PCNN模型的研究都是从时域或图像本身包含信息角度分析参数与模型特性之间的关系,无法全面解释参数对模型特性的影响。从PCNN模型的迭代方程出发,利用离散系统频域分析方法从频域角度对无耦合PCNN模型进行分析,揭示无耦合PCNN模型的动态门限子系统具有低通特性,并确定网络参数a_E的选取范围,同时通过对脉冲发放时刻公式进行推导,得到参数v_E的选取范围。采用傅里叶变换方法分析单个神经元的脉冲发放频率特性和动态门限衰减频率特性,解释无耦合PCNN模型的参数对频域特性的影响。仿真实验结果验证了该理论分析结论的正确性,从频域角度理解无耦合PCNN模型的参数与模型特性之间的关系,为挖掘PCNN模型特性提供一种新的方法。     

Multidecadal Trends in Large-Scale Annual Mean SATa Based on CMIP5 Historical Simulations and Future Projections

Based on observations and Coupled Model Intercomparison Project Phase 5 (CMIP5) results, multidecadal variations and trends in annual mean surface air temperature anomalies (SATa) at global, hemispheric, and hemispheric land and ocean scales in the past and under the future scenarios of two representative concentration pathways (RCPs) are analyzed. Fifteen models are selected based on their performances in capturing the temporal variability, long-term trend, multidecadal variations, and trends in global annual mean SATa. Observational data analysis shows that the multidecadal variations in annual mean SATa of the land and ocean in the northern hemisphere (NH) and of the ocean in the southern hemisphere (SH) are similar to those of the global mean, showing an increase during the 1900–1944 and 1971–2000 periods, and flattening or even cooling during the 1945–1970 and 2001–2013 periods. These observed characteristics are basically reproduced by the models. However, SATa over SH land show an increase during the 1945–1970 period, which differs from the other hemispheric scales, and this feature is not captured well by the models. For the recent hiatus period (2001–2013), the projected trends of BCC-CSM1-1-m, CMCC-CM, GFDL-ESM2M, and NorESM1-ME at the global and hemispheric scales are closest to the observations based on RCP4.5 and RCP8.5 scenarios, suggesting that these four models have better projection capability in SATa. Because these four models are better at simulating and projecting the multidecadal trends of SATa, they are selected to analyze future SATa variations at the global and hemispheric scales during the 2006–2099 period. The selected multi-model ensemble (MME) projected trends in annual mean SATa for the globe, NH, and SH under RCP4.5 (RCP8.5) are 0.17 (0.29) °C, 0.22 (0.36) °C, and 0.11 (0.23) °C·decade⁻¹ in the 21st century, respectively. These values are significantly lower than the projections of CMIP5 MME without model selection.     

谐振子的辛欧拉分析方法

针对理想简谐振子力学模型,研究了其守恒律,并利用辛欧拉格式分析简谐振子振动过程.首先给出了谐振子系统的平方守恒律、周期守恒律和相差守恒律.构造了谐振子的普通欧拉格式和辛欧拉格式,研究了两种格式下三种守恒律各自的保持情况.模拟结果显示:辛欧拉格式能够精确保持时域守恒律(平方守恒律),但无法保持频域守恒律(周期守恒律和相差守恒律).如要克服辛欧拉格式的不足,需按邢誉峰教授提出的方法进行校正.     

A relativistic extension of the complex scaling method using oscillator basis functions

We develop the complex scaling method within the relativistic framework by expanding the Dirac spinors in the complete set of eigensolutions of a harmonic oscillator potential, and present the theoretical formalism of describing the discrete bound and resonant states on the same footing. Based on a well established and frequently used model, we demonstrate the utility and applicability of the extended method and examine the stability of the results with respect to the variations of the parameters of the model. Satisfactory agreements are found for all the calculated results in comparison with some other calculations in references. Especially, the present calculation in the nonrelativistic limit gives a consistent result with that in the nonrelativistic calculation.     

基于卫星信号实现高精度时钟的设计

高精度时钟是通信网时间同步的基础,介绍了接收卫星导航定位系统的定时信号,校正本地晶振的输出,实现高精度时钟的设计方法。从高精度时钟的总体设计、硬件设计,针对硬件实现的关键技术展开阐述,按照ITU-T G．811标准的表征频率精确度和稳定度进行了测试,测试结果分析完全满足标准要求的指标。