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。     

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。     

仿真软件在高频电路实验教学中的应用

Multisim10是原理电路设计、电路功能测试的仿真软件.该文利用Multisim10对高频电路中的功率放大器和正弦波振荡器进行了分析,其结果符合理论推导.将Multisim10引入到高频实验教学中,不但能提高学生的学习兴趣,帮助学生更好理解原理电路以及相关特性的测试方法,而且还能提高学生的电路设计能力.     

低功耗宽调谐范围锁相环设计

针对传统锁相环输出频率范围有限、功耗大的缺陷,通过对压控振荡器震荡机理进行理论分析,设计了一款用于时钟发生器的低功耗、宽调谐范围、低相位噪声锁相环。该锁相环采用了新型可编程、低调谐增益、低功耗的环形振荡器,达到了宽频率输出范围、低相位噪声、低功耗的目的,采用SMIC公司0.18um混合信号工艺,用Cadenced的Hspice仿真工具进行仿真,在1.8V电源电压供电情况下获得了50MHz~1.7GHz的频率锁定范围和1.8mW~2.3mW的较低功耗。单边带相位噪声在10KHz频偏处为-104dBc/Hz.。     

A current‐mode tunable low‐supply‐voltage ring oscillator

A new circuit topology using a current‐mode low‐pass filter for sinusoids has been presented. The technique is relatively simple, in the proposed circuit, only three identical current‐mode low‐pass filters are connected to each other to realize the small signal path. No external passive components are required except for three capacitors. When compared with LC oscillators, the die area of this work, without inductors, is much smaller. When compared with voltage‐mode ring oscillators, the supply voltage of this work is much lower. As a particular example, a 2.4 GHz, 1.2‐V power supply, 5‐mW sinusoidal oscillator is demonstrated. The oscillation frequency is tuned by the value of that three capacitors, over ～900 MHz, and the tuning range is 37.5%. The phase noise results in ?94 and ?120 dBc/Hz at 1 and 10 MHz from the carrier, respectively. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

A piecewise variational iteration method for treating a nonlinear oscillator of a mass attached to a stretched elastic wire

In this paper, we introduce a piecewise variational iteration method for treating a nonlinear oscillator of a mass attached to a stretched elastic wire. For the nonlinear oscillator, the present method can produce a good approximation to the exact solution in a very large region, while the standard variational iteration method (VIM) gives a good approximation only in a small region. The numerical results obtained show that the present method does not share the drawback of the standard VIM and can provide very accurate analytical approximate solutions for both small and large values of the oscillation amplitude and parameter.