Noise Analysis of Nonlinear Feedback Oscillator with AM-PM Conversion Coefficient

The noise of a microwave nonlinear feedback oscillator with AM-PM conversion coefficient is analyzed. The oscillation wave is divided into a carrier and noise sidebands. It is assumed that the noise sideband is the first-order perturbation to the carrier wave and can be superposed with each other. The amplitude and frequency of the carrier are graphically determined by the "device-load line" method, considering the nonlinearity of the amplifier. In order to take the AM-PM conversion effect of a nonlinear amplifier into account, the "transfer matrix" for the small AM and PM sideband components which has amplitude-dependent diagonal and off-diagonal terms is introduced as an extension of the incremental describing function. The spectra of the oscillator noise and their dependence on operating conditions can be easily calculated by using these transfer matrices. The AM and PM noise spectra are measured when a traveling-wave tube is used as an amplifier. The measured values well agree with the calculated ones.     

Miller Theorem for Weakly Nonlinear Feedback Circuits and Application to CE Amplifier

The paper presents the derivation of Miller formulas for weakly nonlinear feedback networks. The expressions found are simple and compact and constitute a generalization of the well-known linear case.      

Components for Microwave Integrated Circuits with Evanescent-Mode Resonators

The electrical performance of active microwave components for radio link systems, which have been realized utilizing evanescent-mode resonators, is described. This waveguide-below-cutoff technique is shown to be an alternative to the techniques established before now.     

基于非线性扰动分析的振荡器相位噪声研究

介绍了Jayanta Mukherjee的振荡器相位噪声理论,该理论基于非线性扰动分析,利用数值解析与电路参数相结合的方式对相位噪声进行研究,分析了不同种类噪声源的影响。设计了理想振荡器和交叉耦合差分压控振荡器进行电路验证分析。把数值解析得到的相位噪声与实际电路仿真结果进行比较,验证了非线性扰动分析在相位噪声研究中的有效性,进一步揭示了相位噪声的物理含义。     

基于硅基微环谐振器的光学导向逻辑器件

光学导向逻辑器件是采用光开关网络执行逻辑运算的典型应用,光学网络中每一个开关的状态由施加到该开关的电学布尔信号决定。网络中每一个光开关的操作都是独立于其他光开关的操作,并且操作运算结果以光速在网络中传播。因此,光学导向逻辑器件具有非常高的运行速度,且总延迟非常小。硅基微环谐振器由于其尺寸小、功耗低、与CMOS工艺兼容等特性成为构建光学导向逻辑器件的理想单元器件。基于硅基微环谐振器的光学导向逻辑器件很容易实现大规模集成和低成本制备,已经提出并实现的基于硅基微环谐振器的光学导向逻辑器件包括"或/或非"、"与/与非"、"异或/同或"、编码器、译码器和半加器等。回顾了本课题组基于硅基微环谐振器实现的光学导向逻辑器件的研究成果和该领域的最新发展。     

Analysis of Microstrip Circuits Coupled to Dielectric Resonators

A lumped element circuit model is introduced to represent coupling between a cylindrical dielectric resonator and a microstrip line. The external Q of the structure is computed and compared to experimental data obtained with three different resonators.     

相位共轭反馈对外腔VCSEL非线性的控制

提出了相位共轭镜（PCM）与外腔垂直腔面发射激光器（VCSEL）相结合的双耦合腔结构,利用相位共轭反馈（PCF）来控制外腔VCSEL的非线性特性,并与用普通光反馈控制非线性特性的情形进行了比较。结果表明：与普通平面镜相比,PCM对放置位置的变化（波长量级）不敏感且PCM反馈可使外腔VCSEL的稳定范围增大;以外腔反射率在5～7ns^-1间变化的功率分岔图为例发现,PCF可抑制多周期和混沌等不稳定状态,控制VCSEI。输出在单周期或倍周期状态;通过PCF和外腔反馈的共同作用。可得到更高频率的单周期或倍周期输出,实现对VCSEL动态特性控制更加容易。     

文氏电桥振荡电路设计方法

本文在详细分析典型文氏电桥正弦波振荡电路工作原理的基础上,推出一套该电路设计方法.笔者在阐述设计方法时,不仅给出了在波形指标要求下选择电路中元器件参数的计算公式和设计步骤,而且还介绍了抑制总谐波失真的方法与措施,并且通过一则设计实例及其仿真实验检验了该设计方法的正确性.     

Cylindrical Dielectric Resonators and Their Applications in TEM Line Microwave Circuits

A cylindrical sample of low-loss high epsilon/sub r/ placed between two parallel conducting plates perpendicular to the sample axis forms a microwave resonator. A simple approximate method for predicting the resonant frequencies of the TE modes of this structure is developed. The method becomes exact for the fitting case of this structure which is known as a dielectric post resonator. In all cases, the accuracy of the method is shown to be better than 3.5 percent. The TE/sub 01delta/ mode chart presented allows the determination of the resonant frequency and the tuning range of any cylindrical dielectric resonator for which epsilon/sub r/ >or= 10. The properties of the dielectric resonator as a TEM line element are demonstrated experimentally.     

Compact Grating Structure for Application to Filters and Resonators in Monolithic Microwave Integrated Circuits

Possible high-Q circuits based on a new crosstie overlay slow-wave structure are proposed for monolithic microwave integrated circuits. Configurations and results of slow-wave factors are presented. This structure is used for construction of a frequency-selective reflector with a compact size. The effect of loss is considered.     

The Oscillator Spectra Improving by a Compact System of Coupled Resonators

The results of the experimental research of a dipole-aperture line (DAL) formed by two coupled cylindrical slot lines are presented. It is shown that such structure can interact actively with the field of an open quasi-optical resonator. Conceptual possibility of technical realization effective coupling of an open resonator with the load by means of waveguide structures of DAL type having the quasi-dipole patterns of scattered fields is proved.     

纳机械谐振器的非线性特性分析

纳机械谐振器有几百兆甚至更高的工作频率,本文利用达芬方程作为纳机械谐振器的动力学方程,用数值方法求解了电磁驱动纳机械谐振器的动态特性,计算表明谐振器有明显的非线性特性,与国外已有的实验结果相符合,该分析方法可以为纳机械混频器设计提供参考。     

时空域位相调制型光学谐振腔的模式

提出一种含有时空位相调制元件的光学谐振腔 ,利用空间 -频率域的相干模式理论对这种谐振腔的模式作了分析和数值模拟。结果表明 ,对固定位相片 ,腔内光场是完全相干的 ,在一定参数下 ,在一镜面上可得到平顶光束 ;对随机微扰型位相片 ,输出模式是部分相干的 ,在合适参数下 ,也可得到平顶光束。     

Optical Phase Locking by Local Oscillator Phase Dithering

A new type of optical phase-locked loop (OPLL), called the dither loop, is mathematically analyzed. The dither loop extracts a phase-error signal by applying a small phase disturbance to the local oscillator laser, and synchronously demodulating the resulting power fluctuation in the output signal of the receiver. The dither loop is superior to other OPLL designs, because it does not need the transmission of a residual carrier, it employs a 180deg/3-dB hybrid, an ac-coupled front end, and it accepts a large variety of input signals. Furthermore, in a dither loop, the amount of power which is fed to the phase-locking branch can be adaptively controlled within the receiver. The analysis first focuses on an expression for the phase detector gain in a dither loop. Using a linearized model, the phase-error variance due to phase dithering, white frequency noise induced phase noise and shot noise is evaluated. A simplified expression for the power penalty generated by the phase dither signal is presented. In a more complex calculation, the overall power penalty due to phase dithering and the residual phase error is found. This allows us to synthesize a design rule for dither loops with optimum performance measures. The design rule determines all relevant system parameters, based on specified values of the system bit rate, the laser linewidth, the photodiode responsivity and the required bit-error rate     

Nonlinear Resonant Circuits for Microwave Low Power Limiters

The letter comprises an analysis of nonlinear coupled resonant circuits for application in limiting low power microwave signals. It presents a novel approach to the use of the resonant circuit containing a nonlinear element which concerns obtaining power dependence of the quality factor and transmission losses without tuning resonant frequency. The basic theory of the single circuit is presented and examples provided of simulations in Microwave Office and measurements results of the designed two-stage limiter. The effect of transforming the input signal amplitude causes this type of circuit to be power-sensitive and allows to limit low power signals.     

A Novel Formalism for Partially Defined Asynchronous Feedback Digital Circuits

In contrast to combinational logic and master clocked sequential logical, asynchronous feedback circuits are partially defined due to analogous meta-stabilities. We present a novel formalism to exactly explore this digitally assisted analog phenomenon in order to build up a representative test bench that is able to enforce race constraints (meta-stable behavior) for non-deterministics, instabilities as well as for oscillations in feedback structures. Further, we introduce our definitions for consistently modeling under state transition graphs, we provide all entities for modeling asynchronous feedback structures and state our proposed methodology with an exemplary asynchronous circuitry. The given example is explained at a high level of abstraction, all data for revision is provided, too. The approach seems to be capable to test for meta-stabilities, analog behavior in feedback digital structures.     

Analog VLSI Excitatory Feedback Circuits for Attentional Shifts and Tracking

In this paper we present analog very large-scale integrated(VLSI) circuits that perform the selection process for attentivevisual processing. These circuits use excitatory feedback ina winner-take-all computation to produce a hysteresis in theselection from one location to the next. We present several alternativeforms of excitation that can be used to enhance surrounding regionsof the presently attended location. Each form of excitation isdiscussed and experimental results from a one-dimensional arrayare presented. We also demonstrate the performance of these circuitswithin a system that receives optical inputs and outputs a singlevoltage that encodes the position of attention. The system demonstratesthe potential use of these excitatory feedback circuits for electronictracking of a stimulus within a noisy environment.     

蔡氏电路连续变量反馈同步的优化设计

本文研究蔡氏电路连续变量反馈同步的优化设计。从控制电路简单实用出发，选择双变量线性反馈单点控制同步方案，并对反馈向量实行抗干扰优化设计。设计实例的数字仿真和电路实验表明，用该方法设计的蔡氏电路同步系统具有较强的抗干扰能力。     

非线性扬声器系统的直接反馈线性化

对通常静态状态反馈中所使用的控制定律采用了一种新型的直接形式表过法它利于扬声器系统的线性化。与积分去耦形式相比，计算效率更高，需要的扬声器参晚少，而且易于在使用定点格式的信号处理上实现。