集成运算放大器负反馈电路的稳定性分析

介绍集成运算放大器负反馈电路的稳定性判定及不稳定因素的解决办法。     

耦合蔡氏电路中混沌同步的充分必要条件

本文从系统稳定方面分析了系统同步，给出了一个耦合蔡氏电路同步的判定准则，由此扩大了同步耦合参数的判定范围。我们还依据准则给出了一个近似判定方法。数据模拟表明了近似判断方法的正确性和可行性。     

增强条件/判定覆盖(RC/DC)准则的研究

软件结构测试中控制流测试准则非常重要,为了克服软件测试中修改条件/判定覆盖准则(MC/DC)难于发现"错误动作"这类错误,在研究并继承MC/DC准则的判定条件的基础上,增加了新的判定条件:当改变一个测试判定条件时,保持判定的值不变.提出了新的测试覆盖准则--增强条件/判定覆盖准则(RC/DC),能够有效提高软件测试的强度.通过对典型实例的分析,验证了该准则的有效性.     

有线电视系统质量指标的极限裕量分析

提出有线电视系统质量指标极限裕量和“上裕量”、“下裕量”的概念以及测量和标示方法,分析引起极限裕量降低的原因,提出有利于促进极限裕量提高的方法和几条工作原则。     

扬声器中的负反馈

电负反馈在电子线路中应用很广,但声负反馈的应用则远没有电负反馈应用得那么普遍。R·科内尔给出了一些在低频扬声器系统中应用声反馈的实验方法。     

高保真的新武器（一）——MFB磁负反馈技术原理

一，什么是磁负反馈？ 什么是磁负反馈，简单扼要的说。就是从磁性换能器如扬声器等的感应线圈上提取反馈信号，组成负反馈电路的负反馈系统叫磁负反馈（HFB）。它与以往常见的负反馈电路的主要区别是：常见的负反馈电路是在单一的电信号体系内完成取样、反馈的。原理单一、简单。MFB是在电生磁、磁生力发声的换能器件上，磁生力的同时也生电（磁生电）并提取电信号作为负反馈信号并组成磁负反馈（MFB）。看起来走了一个大弯子。     

高保真的新武器(一)——MFB磁负反馈技术原理

一、什么是磁负反馈?什么是磁负反馈,简单扼要的说,就是从磁性换能器如扬声器等的感应线圈上提取反馈信号,组成负反馈电路的负反馈系统叫磁负反馈(MFB)。它与以往常见的负反馈电路的主要区别是:常见的负反馈电路是在单一的电信号体系内完成取样、反馈的。原理单一、简单。MFB是在电生磁、磁生力发声的换能器件上,磁生力的同时也生电(磁生电)并提取电信号作为负反馈信号并组成磁负反馈(MFB)。看起来走了一个大弯子。也许有人会说,音响电路越简洁越好,已经有电压负反馈、电流负反馈等,不是电压负反馈还有弊病吗?干吗还要MFB呢,不是多此一…     

序列检测系统参数的优化

以某型炮位侦察校射雷达为实际工程背景,详细讨沦了其序列检测系统的检测性能,并应用最优化方法得出其最佳门限和最佳判定准则。     

基于PCNN图像分割新算法

在原有PCNN的基础上提出一种新的参数自适应PCNN模型,该模型中的各参数均由像素点本身决定,而不受人为的外界干涉,因此,该算法在图像处理领域有较好的运用价值。此外提出另一类分割判定准则——最大相关系数判定准则。最后通过对3种不同的图像分割实验结果分析后得出。该算法和最大相关系数判定准则在图像分割领域中具有较强的适应性和较好的辅助意义。     

用加速度负反馈抑制差速振荡

根据雷达、卫星通讯天线伺服系统双电机驱动中存在的差速振荡问题，提出了在双电机驱动伺服环路中引入加速度负反馈解决的方案。首先对加速度负反馈的原理从传递函数结构、网络校正曲线进行了分析，说明双电机驱动环路内引入加速度负反馈方案是可行的。然后把加速度负反馈设计应用在某雷达方位支路双电机驱动环路中，列举了测试结果。证实了用加速度负反馈可以有效地抑制双电机驱动系统中的差速振荡产生。且电路简单、调试方便。     

Nonlinear dynamics of a semiconductor laser with delayed negative optoelectronic feedback

Nonlinear dynamics of a semiconductor laser with delayed negative optoelectronic feedback are studied both numerically and experimentally. Mappings of the dynamic states and bifurcation diagrams are compared between a delayed negative optoelectronic feedback system and a delayed positive optoelectronic feedback system. Both systems follow a quasiperiodic route to chaos, where regular pulsing, quasiperiodic pulsing, and chaotic pulsing states are observed. Frequency-locked pulsing states are also found in a delayed negative optoelectronic feedback system, but not in a delayed positive optoelectronic feedback system. These frequency-locked pulsing states are experimentally observed to exhibit a harmonic frequency-locking phenomenon, where the pulsing frequency is locked to a harmonic of the delay loop frequency instead of the delay loop frequency itself. The rotation numbers of these frequency-locked pulsing states show a Devil's staircase structure.     

Synthesis of zero-admittance converter

A method of synthesizing a power conversion system which converts a finite value of an admittance to zero, with associated finite voltage and zero current, is presented. The synthesis method comprises a positive voltage feedback within a negative current feedback. The positive feedback loop incorporates a block of exactly specified nature and value of its transfer function providing for the zero-admittance algorithm. The negative feedback loop controls stability and dynamics of the system. A particular derivation of the zero-admittance power converter is applied in synthesizing a load-independent constant-current switch-mode power converter     

A Heuristic Model for the Human Vergence Eye Movement System

A heuristic feedback system model for the human disparity-vergence eye movements is described. The system has been modeled as a continuous negative feedback system with a modified integral-derivative controller, a time-delay element, and a third-order plant. Simulation studies of the model responses for both step and sinusoidal responses fit the experimentally obtained results.     

虚实结合负反馈放大电路性能分析实验

负反馈放大电路实验是模拟电子技术中涉及知识点较多的实验,而传统的负反馈放大电路实验受时空的制约,教学效果不理想。本文采用的虚实结合负反馈放大电路实验系统解决了线下实验和现有仿真软件器件为虚拟器件的不足,能够全面地对电路的性能进行分析和研究。本电路系统学生可以随时随地进行实验操作与实验复习,教学方法灵活多样,提高了教学质量。     

利用回路增益分析负反馈放大电路

目前，方框图法是被广泛使用的分析负反馈放大电路的方法。但用其求电路的增益时，不同的组态要用不同的方法，因而比较复杂繁琐。本文介绍另外一种求增益的方法；首先直接由负反馈放大电路求出回路增益，再利用反馈系数得到负反馈放大电路的增益，最后计算输入电阻、输出电阻。它的优点是负反馈放大电路的增益简单易求。     

基于环路增益的负反馈放大电路分析

文献[1]根据|1+AF|来判断放大电路反馈极性和负反馈放大电路产生自激振荡的条件有不当之处,容易给学生造成误解。本文利用环路增益AF来判断放大电路反馈极性、反馈深度并讨论稳定性。首次采用环路增益的奈奎斯特图来分析反馈极性、反馈深度和稳定性。实验结果表明环路增益奈奎斯特图的成功引入,非常简单直观的解决了文献[1]中的不当之处,并给出了判断放大电路反馈的正负极性、反馈深度和稳定性的准确描述。     

具有自动增益控制的射频振荡器稳定性分析

设计了一个具有自动增益控制(AGC)的电路来稳定射频功率振荡器的输出幅度,然而在加入AGC负反馈环路之后,该环路可能会产生自激振荡,使得振荡器输出的幅度更加不稳定。通过对整个电路系统传递函数的分析,采用调节反馈电路中三极管发射极电阻阻值的方法,使该电路工作在稳定的状态,进而达到稳定振荡器输出幅度的目的。     

Feedback multiplier flat-panel television: IV—Anode sensing

Anode sensing is a negative feedback circuit technique that allows feedback multipliers with inherently nonuniform outputs to be used in an electron source array for a flat TV display. Fundamentals are covered including a distinctive characteristic of anode sensing called negative spread. Circuit specifications are calculated based on characteristics of experimental feedback multiplier cells and required output uniformity. Some additional system problems are discussed.     

A new SVM-based relevance feedback image retrieval using probabilistic feature and weighted kernel function

Relevance feedback (RF) is an effective approach to bridge the gap between low-level visual features and high-level semantic meanings in content-based image retrieval (CBIR). The support vector machine (SVM) based RF mechanisms have been used in different fields of image retrieval, but they often treat all positive and negative feedback samples equally, which will inevitably degrade the effectiveness of SVM-based RF approaches for CBIR. In fact, positive and negative feedback samples, different positive feedback samples, and different negative feedback samples all always have distinct properties. Moreover, each feedback interaction process is usually tedious and time-consuming because of complex visual features, so if too many times of iteration of feedback are asked, users may be impatient to interact with the CBIR system. To overcome the above limitations, we propose a new SVM-based RF approach using probabilistic feature and weighted kernel function in this paper. Firstly, the probabilistic features of each image are extracted by using principal components analysis (PCA) and the adapted Gaussian mixture models (AGMM) based dimension reduction, and the similarity is computed by employing Kullback–Leibler divergence. Secondly, the positive feedback samples and negative feedback samples are marked, and all feedback samples’ weight values are computed by utilizing the samples-based Relief feature weighting. Finally, the SVM kernel function is modified dynamically according to the feedback samples’ weight values. Extensive simulations on large databases show that the proposed algorithm is significantly more effective than the state-of-the-art approaches.     

A model for the integrity assessment of ageing repairable systems

The failure rate of mechanical repairable systems that deteriorate with time due to ageing can usually be visualized by a bathtub curve. This study shows that an equation that is valid in other respects for describing creep curves can easily be deduced from functional forms of the failure rate of mechanical repairable systems. Creeping pieces can be considered repairable systems that evolve under an applied load, as combining positive and negative feedback loops. More generally, this can be extended to mechanical repairable systems, the negative feedback loops corresponding to repair and overhaul operations. The equation describing creep curves reflects the ageing of mechanical repairable systems. A critical time at which the system can no longer be restored to full performance, in spite of repair and/or replacement of subparts, can then be predicted. An application example is given using published failure data corresponding to a submarine main-propulsion diesel engine. The proposed model should apply every time that mechanical system ageing is expressed by a bathtub curve