文氏桥式振荡电路特性及数值仿真分析

正弦波振荡电路是模拟电路课程的基本教学内容,几乎所有的教材都采用反馈的概念来分析正弦振荡电路的特性.本文通过列写文氏桥式振荡电路的电路方程,分析了该电路的振荡特性,并采用数值仿真的方法模拟起振条件,得到了与现有教材对该电路分析一致的结果.上述分析结果可供讲授电路理论及模拟电路课程的教师参考.     

Lapunov’s functions usage in radio circuits’ theory

When analyzing linear differential equations’ stability using Lapunov’s second method, Lapunov’s functions are usually chosen in quadratic form. In radio circuits’ theory Lapunov’s second method by force of existing traditions is applied in rarer cases than for example in mechanics or astronomy. In this article several modifications of the Lapunov’s function are suggested on parametric circuit example. Method which is used here applies to linear radio circuits of general type.     

压电微悬臂梁微弱压电信号检测

压电微悬臂梁是一种利用压电元件的逆压电效应驱动微悬臂梁使其振动，并利用压电元件的压电效应来检测梁的变形量的集成微驱动器和微传感器。文中讨论了压电微悬臂梁中的压电元件的两种等效电路模型，并且提出了检测微压电信号的检测系统以及两种前放电路。在检测微悬臂梁频率响应特性的实验中得到了较好的结果。     

CMOS射频集成电路：成果与展望

CMOS射频集成电路的研究和制作将大大拓展集成电路的应用空间,文章介绍了采用CMOS工艺集成射频电路研究中所取得的成果,评述了其中存在的问题,最后指出了该领域中未来的几个研究方向。     

由RTD/MOSFET构成的新型振荡电路

基于一种新型的振荡机制,利用共振隧穿二极管(RTD)固有的负阻和双稳特性,与MOSFET器件相结合,首次实现了工作频率约为25MHz的RTD/MOSFET高频振荡电路.文章首先从理论上深入分析了该电路的振荡机理,然后通过高级设计系统(ADS)软件仿真和实验验证了此振荡电路的正确性.该电路的实现有望解决传统的基于RTD的振荡电路的功率限制问题,如果进一步用高电子迁移率晶体管(HEMT)等高频、高速器件取代MOSFET,可以在很大程度上提高这一电路的工作频率,并可实现RTD/HEMT的单片集成.因此该振荡电路在微波和射频领域具有广阔的应用前景.     

Implementation of quantum optical tristate oscillators based on tristate Pauli-X, Y and Z gates by using joint encoding of phase and intensity

Oscillator circuit has the significant role to always repeat the same signal at the output after certain time interval. In quantum computing, intensity and phase of light signal can be made oscillatory at the output of a quantum optical oscillator circuit. In this paper, we have implemented quantum optical tristate oscillator circuits based on tristate Pauli-X, Y and Z gates using phase and intensity encoding technique of light signal. Here, three different oscillator circuits are developed. The phase of light signal is chosen as the oscillating parameter in all proposed circuits. The truth tables and oscillating phase diagrams are also shown for each oscillator circuit in this paper. The operation of one of the oscillator circuits is simulated with MATLAB to prove its feasibility.     

脉冲激光测距机的测距误差分析

从理论上分析了脉冲激光测距机的测距误差,主要由晶体振荡器的振荡频率稳定度、接收系统的响应时间以及激光脉冲宽度三个因素的影响所致,测距误差范围是-5m～10m.     

多回高压输电线路产生的无线电干扰分析

在规划设计，中关村软件园东侧将建设包括4回220kV四分裂导线，6回110kV单导线构成的10回高压输电线路，为了评估该高压线路走廊对软件园的电磁环境影响。在简述高压输电线路由于电晕产生的无线电干扰的基础上，分析单回220kV四分裂导线。220kV不采用分裂导线两种情况下的无线电干扰水平，由此估计该10回输电线路产生的无线电干扰水平，结果表明，该高压线路走廊产生的无线电干扰水平符合国家标准GB15707-1995《高压交流架空送电线无线电干扰限值》相应的要求。     

Analysis of free processes in time varying circuit by means of generalized characteristic equations method

Developing methods of analysis of free processes in time varying circuit is important both for time varying and nonlinear radio circuits. The principle of linear connection brings together processes in time varying and nonlinear circuits. It is of special interest to extend the existing methods developed for radio circuits with stable parameters to time varying circuits. This article is devoted to one of such methods-the method of characteristic equations for differential equations with fixed factors.     

基于FPGA的电台接口转换模块设计

目前市场上电台接口转换模块大多都采用模拟电路,其带来稳定性差,工艺复杂等缺陷。通过采用数字信号处理技术来处理信号通信,提高信号的传输速率和降低传输的误码率,并提高系统的稳定性,节省信道资源。这里采用FPGA作为核心芯片来设计和开发,利用DSP Builder来仿真FFT实验,用QuartusⅡ软件开发设计此接口转换模块,最终获得的模块电路系统稳定,PTT信号更纯净。     

RF 集成电路工艺探讨¹

射频集成电路的研究和制作将大大拓展集成电路的应用空间，本文介绍了当今RF的主流工艺，并分别对基于硅的深亚微米CMOS工艺在RF设计中的可行性和困难进行了研究，评述了其中存在的问题，最后提出了该领域中未来的发展前景。     

Automatic variance control and variance estimation loops

A closed-loop servo approach is applied to the problem of controlling and estimating variance in nonstationary signals. The new circuit closely resembles, but is not the same as, automatic gain control, which is common in radio and other circuits. The closed-loop nature of the solution to this problem makes this approach highly accurate, and it can be used recursively in real time.     

多频道通信程控频率合成器

本文以大规模锁相环集成电路为中心,提出了一种可程控的频率合成技术。探索了多频道无线通信频率切换的方法,并给出了电路设计参数,图表以及微机接口的硬件和软件流程。有效地解决了多频道通讯中的程控频道切换的问题。     

Characteristics of negative-resistance nonsinusoidal oscillators

This paper discusses the general characteristics of negative-resistance oscillators for which the voltage waveform across the active device consists not only of the fundamental voltage component but also of substantial harmonic voltage components. It is shown that a stability criterion, equivalent to that described by Kurokawa for sinusoidal voltage oscillators, must be satisfied at each frequency. The waveform components are derived from the fact that, when oscillating, the diode dynamic admittance at each frequency must always be equal to the negative of the load admittance at that frequency. The analysis is applied to two different practical circuits which give rise to LSA relaxation oscillations and good agreement is obtained between theory and experiment.     

Vertical microstrip transition for multilayer microwave circuits with decoupled passive and active layers

A novel broadband (including dc) microstrip-to-microstrip vertical transition for multilayer microwave circuits is proposed. This transition solves the problem of the discontinuity typically appearing in via hole transitions between two microstrip transmission lines in different layers. An analogy existing between this transition and a rectangular coaxial line is discussed. A parametric study alongside with the experimental results of the transition are presented. Reduction of local oscillator to radio frequency leakage in a mixer with this transition is demonstrated.     

不同阶Colpitts混沌振荡电路的性能对比分析

宽带混沌信号拥有良好的相关特性、低截获概率和高保密性等优点.本文介绍了一种基本的混沌信号产生电路-Colpitts振荡电路,在此基础上,对该电路作了相关改进,同时通过仿真对它们的性能进行了分析比较.结果显示:对三阶Colpitts振荡电路的改进方法是可行的;三阶Colpitts振荡电路频谱较为集中,且自相关性能差,应用...     

Analysis,properties and potential performance capabilities of a parametric circuit. Resonance

The principle of linear engagement reads that for any process in a nonlinear circuit it is possible to find an equivalent linear circuit with the same process. This principle points out the significance of a parametric circuit in radio engineering. In radio communications an oscillating circuit performs one of the most important roles providing selectivity. Often nonlinear elements are included in it aiming to improve its quality, but dramatically complicating analysis. Thus parametric circuit analysis and use is of a great importance.     

基于新型重复控制器的高精度摆镜伺服系统研究

为了解决摆镜伺服系统周期速度振荡的问题,采用直流电机作为扫描驱动电机,建立伺服系统的数学模型,根据摆镜扫描的周期性特点,提出了一种改进的重复控制器对伺服系统的转速进行控制,实现结果表明该方法很好的改善了系统的跟踪性能,有效的提高了摆镜扫描的速度稳定性,抑制了电机的振荡现象.     

Stability problem of time varying circuit

Adequate mathematic apparatus of time varying circuit is the system of two linear differential equations of the first order or linear differential equation the second order. In both cases coefficients are functions dependent on argument (time). Enormous number of publications devoted to analysis of this equation stability, and as a result we have obtained many sufficient conditions of stability. Nevertheless available results do not give complete solution of the problem, moreover, there is no analysis of the fact how much well-known stability criteria are approximate to complete solution. In this paper, using radio circuit methods, it is formulated stability problem of time varying circuit in form, convenient for computer analysis.