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第1行： − 此词条暂由彩云小译翻译，未经人工整理和审校，带来阅读不便，请见谅。{{short description|Process where information about current status is used to influence future status}}+ − − + − + − − − 第16行：
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第17行： − + − − 当系统的输出作为输入路由回来，作为形成电路或回路的因果链的一部分时，就发生了反馈。这个系统可以说是自我反馈。因果关系的概念在应用于反馈系统时必须谨慎处理: − + 第33行：
第25行： − {{quote+ − − {引用 − |text=Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole.+ − − 关于反馈系统的简单因果推理是困难的，因为第一个系统影响第二个系统，第二个系统影响第一个系统，导致循环论证。这使得基于因果的推理变得棘手，因此有必要将系统作为一个整体进行分析。 − − |author=Karl Johan Åström and Richard M.Murray − 作者: Richard M.Murray 卡尔·约翰·阿斯特洛姆+ − − |title=''Feedback Systems: An Introduction for Scientists and Engineers''<ref>{{cite book |title=Feedback Systems: An Introduction for Scientists and Engineers |author1=Karl Johan Åström |author2=Richard M. Murray |chapter=§1.1: What is feedback? |chapter-url=https://books.google.com/books?id=cdG9fNqTDS8C&pg=PA1&dq=%22This+makes+reasoning+based+on+cause+and+effect+tricky%22 |isbn= 9781400828739 |year=2010 |page=1 |publisher=Princeton University Press}} Online version found [http://authors.library.caltech.edu/25062/1/Feedback08.pdf here]. − |title=Feedback Systems: An Introduction for Scientists and Engineers<ref> Online version found [http://authors.library.caltech.edu/25062/1/Feedback08.pdf here].+ − + − </ref>}}+ − [ / ref }+ − − − − ==History== − 历史+ − − − Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter economic theory in Britain by the eighteenth century, but it was not at that time recognized as a universal abstraction and so did not have a name.<ref name=mayr>+ − 自我调节机制自古以来就存在，反馈的概念在18世纪开始进入英国的经济理论，但当时并不被认为是一个普遍的抽象概念，因此没有名称。 裁判姓名梅尔+ − </ref>+ − / 参考+ + − The first ever known artificial feedback device was a [[Ballcock|float valve]], for maintaining water at a constant level, invented in 270 BC in [[Alexandria]], [[Egypt]].<ref name=":0">{{Cite book|title=Designing Kinetics for Architectural Facades|last=Moloney|first=Jules|publisher=Routledge|year=2011|isbn=978-0415610346|location=|pages=}}</ref> This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates.<ref name=":0" /> − The first ever known artificial feedback device was a float valve, for maintaining water at a constant level, invented in 270 BC in Alexandria, Egypt. This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates.+ − 第一个已知的人工反馈装置是一个浮子阀，用来维持水的恒定水平，发明于公元前270年的埃及亚历山大。这个装置说明了反馈原理: 低水位打开阀门，上升的水向系统提供反馈，当达到要求的水位时关闭阀门。随着水位的波动，这种情况会以循环的方式再次发生。+ + + − [[Centrifugal governor]]s were used to regulate the distance and pressure between [[millstone]]s in [[windmill]]s since the 17th century.+ − Centrifugal governors were used to regulate the distance and pressure between millstones in windmills since the 17th century.+ − 自17世纪以来，离心调速器就被用来调节风车磨盘之间的距离和压力。 − − − − − − In [[1788]] [[James Watt]] designed his first [[Centrifugal governor]] following a suggestion from his business partner [[Matthew Boulton]], for use in the steam engines of their production. Early [[steam engine]]s employed a purely reciprocating motion, and were used for pumping water – an application that could tolerate variations in the working speed, but the use of steam engines for other applications called for more precise control of the speed. − − In 1788 James Watt designed his first Centrifugal governor following a suggestion from his business partner Matthew Boulton, for use in the steam engines of their production. Early steam engines employed a purely reciprocating motion, and were used for pumping water – an application that could tolerate variations in the working speed, but the use of steam engines for other applications called for more precise control of the speed. − − 1788年，James Watt 根据他的商业伙伴 Matthew Boulton 的建议设计了他的第一台离心式调速器，用于他们生产的蒸汽机。早期的蒸汽机采用纯往复运动，用于抽水——这种应用可以容忍工作速度的变化，但是蒸汽机用于其他应用需要更精确的速度控制。 + + − + − In [[1868]], [[James Clerk Maxwell]] wrote a famous paper "On governors" that is widely considered a classic in feedback control theory.<ref>{{cite journal|last=Maxwell|first=James Clerk|title=On Governors|journal=Proceedings of the Royal Society of London|volume= 16|year= 1868 |pages= 270–283 | doi = 10.1098/rspl.1867.0055 | jstor=112510|doi-access=free}}</ref> This was a landmark paper on [[control theory]] and mathematics of feedback. − − In 1868, James Clerk Maxwell wrote a famous paper "On governors" that is widely considered a classic in feedback control theory. This was a landmark paper on control theory and mathematics of feedback. − − 1868年，詹姆斯·克拉克·麦克斯韦写了一篇著名的论文《论州长》 ，被广泛认为是反馈控制理论的经典之作。这是一个具有里程碑意义的论文控制理论和数学的反馈。 − − − − − − − − The verb phrase "to feed back", in the sense of returning to an earlier position in a mechanical process, was in use in the US by the 1860s,<ref> − − 19世纪60年代，美国开始使用动词短语“ to feedback” ，意思是在机械加工过程中回到较早的位置 − "Heretofore ... it has been necessary to reverse the motion of the rollers, thus causing the material to travel or feed back, ..."+ − − 迄今为止... ... 有必要逆转滚筒的运动，从而使材料移动或反馈，... .. − − HH Cole, "Improvement in Fluting-Machines", [http://www.google.co.nz/patents/US55469 US Patent 55,469 (1866)] accessed 23 Mar 2012. − − HH Cole, "Improvement in Fluting-Machines", [http://www.google.co.nz/patents/US55469 US Patent 55,469 (1866)] accessed 23 Mar 2012. − Hh Cole，《凹槽机器的改进》 ，[ http://www.google.co.nz/patents/us55469美国专利55,469(1866)]于2012年3月23日获得。+ − </ref><ref>+ − / ref+ − − − − "When the journal or spindle is cut ... and the carriage is about to feed back by a change of the sectional nut or burr upon the screw-shafts, the operator seizes the handle..." JM Jay, "Improvement in Machines for Making the Spindles of Wagon-Axles", [http://www.google.co.nz/patents/US47769 US Patent 47,769 (1865)] accessed 23 Mar 2012. − − 2012年3月23日，JM 杰伊，《货车车轴主轴制造机械的改进》 ，[美国 http://www.google.co.nz/patents/us47769专利47,769(1865)]。 − − </ref> and in 1909, Nobel laureate [[Karl Ferdinand Braun]] used the term "feed-back" as a noun to refer to (undesired) ''coupling'' between components of an electronic circuit.<ref>''"...as far as possible the circuit has no feed-back into the system being investigated."'' − − </ref> and in 1909, Nobel laureate Karl Ferdinand Braun used the term "feed-back" as a noun to refer to (undesired) coupling between components of an electronic circuit.<ref>"...as far as possible the circuit has no feed-back into the system being investigated." − − / ref 在1909年，诺贝尔奖得主卡尔·费迪南德·布劳恩使用术语“反馈”作为名词，指的是电子电路元件之间(不希望出现的)耦合。 尽可能地，电路没有反馈到被调查的系统 − + − [ http://www.cdvandtext2.org/braun-nobel-lecture%201909.pdf ]+ − − Karl Ferdinand Braun, [https://www.nobelprize.org/nobel_prizes/physics/laureates/1909/braun-lecture.html "Electrical oscillations and wireless telegraphy"], Nobel Lecture, 11 December 1909. Retrieved 19 Mar 2012.</ref> − − − − 2009年12月11日，诺贝尔卡尔·费迪南德·布劳恩，《 https://www.nobelprize.org/nobel_prizes/physics/laureates/1909/braun-Lecture.html 志《电子振荡与无线电报》。2012年3月19日 / ref + + 第181行：
第115行： − By the end of 1912, researchers using early electronic amplifiers (audions) had discovered that deliberately coupling part of the output signal back to the input circuit would boost the amplification (through regeneration), but would also cause the audion to howl or sing.<ref name="bennett"> + − − 到1912年底，研究人员利用早期电子放大器(音频)发现，故意将输出信号的一部分耦合回输入电路，可以增强放大(通过再生) ，但也会导致音频发出嚎叫或唱歌。 裁判员名字“ bennett” − [https://books.google.com/books?id=1gfKkqB_fTcC]+ − − [ https://books.google.com/books?id=1gfkkqb_ftcc ] − − </ref> This action of feeding back of the signal from output to input gave rise to the use of the term "feedback" as a distinct word by 1920. − − 这种将信号从输出反馈到输入的行为，在1920年引起了“反馈”一词作为一个单独的词的使用。 + + − + − − Over the years there has been some dispute as to the best definition of feedback. According to Ashby (1956), mathematicians and theorists interested in the principles of feedback mechanisms prefer the definition of circularity of action, which keeps the theory simple and consistent. For those with more practical aims, feedback should be a deliberate effect via some more tangible connection. − − 多年来，关于反馈的最佳定义一直存在一些争议。按照阿什比(1956)的说法，对反馈机制原理感兴趣的数学家和理论家更喜欢行动循环的定义，这使得理论简单一致。对于那些有更实际目标的人来说，反馈应该是通过一些更切实的联系而产生的有意的效果。 − {{Quote|[Practical experimenters] object to the mathematician's definition, pointing out that this would force them to say that feedback was present in the ordinary pendulum ... between its position and its momentum—a "feedback" that, from the practical point of view, is somewhat mystical. To this the mathematician retorts that if feedback is to be considered present only when there is an actual wire or nerve to represent it, then the theory becomes chaotic and riddled with irrelevancies.<ref name=Ashby>+ − {{引用 | [实验者]反对数学家的定义，指出这将迫使他们说反馈存在于普通钟摆中... 在它的位置和它的动量之间ーー一种“反馈” ，从实践的角度来看，有点神秘。对此，数学家反驳说，如果只有当有实际的线或神经来表示反馈时，反馈才被认为是存在的，那么理论就会变得混乱，充满了不相关性。 裁判名叫艾希比+ 第217行：
第141行： + − + − − − Focusing on uses in management theory, Ramaprasad (1983) defines feedback generally as "...information about the gap between the actual level and the reference level of a system parameter" that is used to "alter the gap in some way". He emphasizes that the information by itself is not feedback unless translated into action. − − 关注管理理论中的应用，Ramaprasad (1983)将反馈一般定义为“ ... 关于实际水平和系统参数参考水平之间的差距的信息” ，用于“以某种方式改变差距”。他强调，信息本身不是反馈，除非转化为行动。 + + − − ==Types== − − 类型 + + − − ===Positive and negative feedback=== − − 正反馈和负反馈 − − − Maintaining a desired system performance despite disturbance using negative feedback to reduce system error+ − 使用负反馈来减少系统误差，使系统在受到干扰时仍能保持理想的系统性能+ − − An example of a negative feedback loop with goals − − 一个有目标的负反馈循环的例子 − A positive feedback loop example+ − − 一个正反馈循环的例子 − − Positive feedback: If the signal fed back from output is in phase with the input signal,the feedback is called positive feedback. − − − − 正反馈: 如果输出反馈的信号与输入信号同相，这种反馈称为正反馈。 − − − − Negative feedback: If the signal fed back is of opposite polarity or out of phase by 180° with respect to input signal, the feedback is called as negative feedback. − − 负反馈: 如果反馈信号相对于输入信号的极性相反或相位差180，这种反馈称为负反馈。 − − − − As an example of negative feedback, the diagram might represent a cruise control system in a car, for example, that matches a target speed such as the speed limit. The controlled system is the car; its input includes the combined torque from the engine and from the changing slope of the road (the disturbance). The car's speed (status) is measured by a speedometer. The error signal is the departure of the speed as measured by the speedometer from the target speed (set point). This measured error is interpreted by the controller to adjust the accelerator, commanding the fuel flow to the engine (the effector). The resulting change in engine torque, the feedback, combines with the torque exerted by the changing road grade to reduce the error in speed, minimizing the road disturbance. − − 作为负反馈的一个例子，该图可以表示汽车中的巡航控制系统，例如，它与目标速度(如车速限制)匹配。受控系统是汽车，其输入包括来自发动机和来自道路坡度变化(扰动)的组合扭矩。汽车的速度(状态)是用速度计测量的。误差信号是速度计测量的速度偏离目标速度(设定点)。这个测量的误差由控制器来解释，以调整加速器，指挥燃料流到发动机(效应器)。由此产生的发动机扭矩的变化，即反馈，与改变路面坡度所施加的扭矩相结合，以减少速度误差，最大限度地减少道路干扰。 + + − − The terms "positive" and "negative" were first applied to feedback prior to WWII. The idea of positive feedback was already current in the 1920s with the introduction of the regenerative circuit.<ref name=mindell> − − “正面”和“负面”这两个词在第二次世界大战之前首次用于反馈。积极反馈的概念在20世纪20年代随着再生回路的引入已经流行起来 − − {{Cite book − − {引用书 − |author=David A. Mindell+ − 作者: David a. Mindell+ − − |title=Between Human and Machine : Feedback, Control, and Computing before Cybernetics. − − 人与机器之间: 控制论之前的反馈、控制与计算。 − − |year= 2002 − − 2002年 − − |publisher=Johns Hopkins University Press − − 出版商约翰霍普金斯大学出版社 − − |location=Baltimore, MD, US − − | 位置: 美国马里兰州巴尔的摩 − − |url=https://books.google.com/books?id=sExvSbe9MSsC|isbn=9780801868955 − − Https://books.google.com/books?id=sexvsbe9mssc|isbn=9780801868955 − − }} − − }} 第355行：
第215行： − </ref> Friis and Jensen (1924) described regeneration in a set of electronic amplifiers as a case where the "feed-back" action is positive in contrast to negative feed-back action, which they mention only in passing.<ref name=friis>+ − / ref Friis and Jensen (1924)将一组电子放大器中的再生描述为“反馈”作用是积极的，而消极反馈作用只是顺便提到。 名字叫 friis+ − − Friis, H.T., and A.G.Jensen. "High Frequency Amplifiers" Bell System Technical Journal 3 (April 1924):181–205.</ref> Harold Stephen Black's classic 1934 paper first details the use of negative feedback in electronic amplifiers. According to Black: − − 弗里斯、 h.t. 和 A.G.Jensen。“高频放大器”贝尔系统技术杂志3(1924年4月) : 181-205。 / ref 哈罗德·史蒂芬·布莱克1934年的经典论文首次详细阐述了负反馈在电子放大器中的应用。布莱克说: − − − − {{Quote|Positive feed-back increases the gain of the amplifier, negative feed-back reduces it.<ref name=black> − − {引用 | 正反馈增加了放大器的增益，负反馈减少了它。参考名称黑色 − − H.S. Black, "Stabilized feed-back amplifiers", Electrical Engineering, vol. 53, pp. 114–120, January 1934.</ref>}} − − H.s.黑色，“稳定反馈放大器” ，电气工程，第卷。53，pp. 114-120，January 1934. / ref } − According to Mindell (2002) confusion in the terms arose shortly after this:+ − 据 Mindell (2002)说，术语上的混乱是在这之后不久产生的:+ 第391行：
第237行： + + − + − − − − Even prior to the terms being applied, James Clerk Maxwell had described several kinds of "component motions" associated with the centrifugal governors used in steam engines, distinguishing between those that lead to a continual increase in a disturbance or the amplitude of an oscillation, and those that lead to a decrease of the same.<ref name=maxwell> − − 甚至在这些术语被使用之前，詹姆斯·克拉克·麦克斯韦就已经描述了几种与蒸汽发动机中使用的离心调速器相关的“组件运动” ，区分那些导致扰动持续增加或振幅振荡的组件运动，以及那些导致扰动减少的组件运动。 参考名称麦克斯韦 − − − − </ref> − − / 参考 − − 第413行：
第247行： − ====Terminology====+ − 术语+ − − The terms positive and negative feedback are defined in different ways within different disciplines. − − 正反馈和负反馈在不同的学科中有不同的定义。 − − − − the altering of the gap between reference and actual values of a parameter, based on whether the gap is widening (positive) or narrowing (negative). − − 一个参数的参考值和实际值之间的差距的改变，根据差距是扩大(正面)还是缩小(负面)。 − − the valence of the action or effect that alters the gap, based on whether it has a happy (positive) or unhappy (negative) emotional connotation to the recipient or observer. − − 改变差距的行为或效果的效价，取决于它对接受者或观察者来说是否具有快乐(积极)或不快乐(消极)的情感内涵。 − − − − The two definitions may cause confusion, such as when an incentive (reward) is used to boost poor performance (narrow a gap). Referring to definition 1, some authors use alternative terms, replacing positive/negative with self-reinforcing/self-correcting,<ref name="senge"> − − 这两个定义可能会引起混淆，例如当一个激励(奖励)被用来提高不良业绩(缩小差距)。参照定义1，一些作者使用替代术语，用自我强化 / 自我纠正，ref name"senge"替代正面 / 负面 − − {{Cite book − − {引用书 − − |author=Peter M. Senge − − 作者: Peter m. Senge − − |title=The Fifth Discipline: The Art and Practice of the Learning Organization − − 第五门学科: 学习型组织的艺术与实践 − − |year=1990 − − 1990年 − − |publisher=Doubleday − − 出版商双日出版社 − − |location=New York − − | 地点: 纽约 − − |isbn=978-0-385-26094-7 − − [国际标准图书编号978-0-385-26094-7] − − |page=424 − − 第424页 − − |url=https://archive.org/details/fifthdisciplineasen00seng − − Https://archive.org/details/fifthdisciplineasen00seng 第510行：
第288行： − − </ref> reinforcing/balancing,<ref name="sterman"> − − ”加强 / 平衡，裁判姓名””斯特曼” − − John D. Sterman, Business Dynamics: Systems Thinking and Modeling for a Complex World, McGraw Hill/Irwin, 2000. − − 《商业动力学: 复杂世界的系统思考与建模》 ，麦格劳希尔 / 欧文出版社，2000年。 − − </ref> discrepancy-enhancing/discrepancy-reducing<ref name="carver"> − − 矛盾加剧，矛盾减少，名字“ carver” − − Charles S. Carver, Michael F. Scheier: On the Self-Regulation of Behavior Cambridge University Press, 2001 − − 《行为的自我调节》 ，剑桥大学出版社，2001年 − − </ref> or regenerative/degenerative<ref> − − / ref 或 regenerative / destruction ref − − Hermann A Haus and Richard B. Adler, Circuit Theory of Linear Noisy Networks, MIT Press, 1959 − − 赫尔曼 a 豪斯和理查德 b 阿德勒，线性噪声网络的电路理论，麻省理工学院出版社，1959年 − − </ref> respectively. And for definition 2, some authors advocate describing the action or effect as positive/negative reinforcement or punishment rather than feedback.<ref name="skinner"> − − / ref.对于定义2，一些作者主张将行为或效果描述为正 / 负强化或惩罚，而不是反馈。 裁判员名字“ skinner” − − BF Skinner, The Experimental Analysis of Behavior, American Scientist, Vol. 45, No. 4 (SEPTEMBER 1957), pp. 343-371</ref> − − 斯金纳，《行为的实验分析》 ，美国科学家，第一卷。45，No.4(SEPTEMBER 1957) ，pp.343-371 / ref − − Yet even within a single discipline an example of feedback can be called either positive or negative, depending on how values are measured or referenced.<ref> − − 然而，即使是在一个单一的学科中，一个反馈的例子也可以被称为正面或负面的，这取决于如何衡量或引用价值观。 裁判 − − "However, after scrutinizing the statistical properties of the structural equations, the members of the committee assured themselves that it is possible to have a significant positive feedback loop when using standardized scores, and a negative loop when using real scores." − − “然而，在仔细研究了结构方程的统计特性之后，委员会成员确信，在使用标准化分数时，有可能出现显著的正反馈循环，而在使用实际分数时，可能出现负反馈循环。” − − Ralph L. Levine, Hiram E. Fitzgerald. Analysis of the dynamic psychological systems: methods and applications, (1992) page 123</ref> − − 拉尔夫 · l · 莱文，海勒姆 · e · 菲茨杰拉德。动态心理系统的分析: 方法和应用，(1992)页123 / ref − − − − This confusion may arise because feedback can be used for either informational or motivational purposes, and often has both a qualitative and a quantitative component. As Connellan and Zemke (1993) put it: − − 这种混淆可能是因为反馈既可以用于信息目的，也可以用于激励目的，而且往往有定性和定量的组成部分。正如康奈伦和泽姆克(1993)所说: − − − − − − ====Limitations of negative and positive feedback==== − − 负面和正面反馈的局限性 − − While simple systems can sometimes be described as one or the other type, many systems with feedback loops cannot be so easily designated as simply positive or negative, and this is especially true when multiple loops are present. − − 虽然简单的系统有时可以被描述为一种或另一种类型，但许多具有反馈回路的系统不能简单地被指定为正或负，当存在多个回路时尤其如此。 − − − − − − {{Quote|When there are only two parts joined so that each affects the other, the properties of the feedback give important and useful information about the properties of the whole. But when the parts rise to even as few as four, if every one affects the other three, then twenty circuits can be traced through them; and knowing the properties of all the twenty circuits does not give complete information about the system.<ref name=Ashby/>{{rp|page=54}}}} − − − − − − − − ===Other types of feedback=== − − ===Other types of feedback=== − − 其他类型的反馈 − − In general, feedback systems can have many signals fed back and the feedback loop frequently contain mixtures of positive and negative feedback where positive and negative feedback can dominate at different frequencies or different points in the state space of a system. − − In general, feedback systems can have many signals fed back and the feedback loop frequently contain mixtures of positive and negative feedback where positive and negative feedback can dominate at different frequencies or different points in the state space of a system. − − 一般来说，反馈系统可以有多个信号反馈，反馈回路常常包含正反馈和负反馈的混合，其中正反馈和负反馈可以在系统的不同频率或状态空间的不同点占主导地位。 − − − − − − The term bipolar feedback has been coined to refer to biological systems where positive and negative feedback systems can interact, the output of one affecting the input of another, and vice versa.<ref name=Smit> − − The term bipolar feedback has been coined to refer to biological systems where positive and negative feedback systems can interact, the output of one affecting the input of another, and vice versa.<ref name=Smit> − − 双极反馈一词是指生物系统中正反馈系统可以相互作用，一个系统的输出影响另一个系统的输入，反之亦然。 参考名称 smit − − {{cite book |title=Introduction to Bioregulatory Medicine |author1=Alta Smit |author2=Arturo O'Byrne |chapter-url=https://books.google.com/books?id=RzXAOUnCM3oC&pg=PA6 |page=6 |chapter=Bipolar feedback |isbn=9783131469717 |year=2011 |publisher=Thieme}} − − − − </ref> − − </ref> − − / 参考 − − − − − − Some systems with feedback can have very complex behaviors such as [[Chaos theory|chaotic behaviors]] in non-linear systems, while others have much more predictable behaviors, such as those that are used to make and design digital systems. − − Some systems with feedback can have very complex behaviors such as chaotic behaviors in non-linear systems, while others have much more predictable behaviors, such as those that are used to make and design digital systems. − − 一些具有反馈的系统可能具有非常复杂的行为，如非线性系统中的混沌行为，而另一些系统则具有更可预测的行为，如用于制造和设计数字系统的行为。 − − − − − − Feedback is used extensively in digital systems. For example, binary counters and similar devices employ feedback where the current state and inputs are used to calculate a new state which is then fed back and clocked back into the device to update it. − − Feedback is used extensively in digital systems. For example, binary counters and similar devices employ feedback where the current state and inputs are used to calculate a new state which is then fed back and clocked back into the device to update it. − − 反馈在数字系统中被广泛应用。例如，二进制计数器和类似的设备使用反馈，当前状态和输入用于计算一个新的状态，然后反馈回设备并计时以更新它。 − − − − − − ==Applications== − − ==Applications== − − 申请 − − ===Mathematics and Dynamical systems=== − − ===Mathematics and Dynamical systems=== − − 数学与动力系统 − − [[File:Mandel zoom 00 mandelbrot set.jpg|322px|thumb|Feedback can give rise to incredibly complex behaviors. The [[Mandelbrot set]] (black) within a continuously colored environment is plotted by repeatedly feeding back values through a simple equation and recording the points on the imaginary plane that fail to diverge|alt=]] − − Feedback can give rise to incredibly complex behaviors. The [[Mandelbrot set (black) within a continuously colored environment is plotted by repeatedly feeding back values through a simple equation and recording the points on the imaginary plane that fail to diverge|alt=]] − − 反馈可以导致难以置信的复杂行为。[[在一个连续着色的环境中的 Mandelbrot 集(黑色)是通过一个简单的方程重复反馈值并记录想象平面上未能发散的点 | alt ]绘制出来的] − − {{Main|Dynamical system|Chaos theory|Edge of chaos|Control theory}} − − − − By using feedback properties, the behavior of a system can be altered to meet the needs of an application; systems can be made stable, responsive or held constant. It is shown that dynamical systems with a feedback experience an adaptation to the [[edge of chaos]].<ref>{{cite journal|last1=Wotherspoon|first1=T.|last2=Hubler|first2=A.|title=Adaptation to the edge of chaos with random-wavelet feedback|journal=J. Phys. Chem. A|date=2009|doi=10.1021/jp804420g|pmid=19072712|volume=113|issue=1|pages=19–22|bibcode=2009JPCA..113...19W}}</ref> − − By using feedback properties, the behavior of a system can be altered to meet the needs of an application; systems can be made stable, responsive or held constant. It is shown that dynamical systems with a feedback experience an adaptation to the edge of chaos. − − 通过使用反馈属性，系统的行为可以改变以满足应用程序的需要; 系统可以变得稳定、响应或保持不变。结果表明，具有反馈经验的动力系统具有对混沌边界的适应性。 − − − − − − ===Biology=== − − ===Biology=== − − 生物学 − − {{See also|Homeostasis|Allostasis}} − − − − In [[biology|biological]] systems such as [[organism]]s, [[ecosystem]]s, or the [[biosphere]], most parameters must stay under control within a narrow range around a certain optimal level under certain environmental conditions. The deviation of the optimal value of the controlled parameter can result from the changes in internal and external environments. A change of some of the environmental conditions may also require change of that range to change for the system to function. The value of the parameter to maintain is recorded by a reception system and conveyed to a regulation module via an information channel. An example of this is [[insulin oscillation]]s. − − In biological systems such as organisms, ecosystems, or the biosphere, most parameters must stay under control within a narrow range around a certain optimal level under certain environmental conditions. The deviation of the optimal value of the controlled parameter can result from the changes in internal and external environments. A change of some of the environmental conditions may also require change of that range to change for the system to function. The value of the parameter to maintain is recorded by a reception system and conveyed to a regulation module via an information channel. An example of this is insulin oscillations. − − 在诸如生物体、生态系统或生物圈等生物系统中，在某些环境条件下，大多数参数必须保持在围绕某一最佳水平的狭窄范围内。受控参数最优值的偏差可以由内外环境的变化引起。一些环境条件的改变也可能需要改变这个范围来改变系统的功能。要维持的参数值由接收系统记录并通过信息通道传输到调节模块。这方面的一个例子是胰岛素振荡。 − − − − − − Biological systems contain many types of regulatory circuits, both positive and negative. As in other contexts, ''positive'' and ''negative'' do not imply that the feedback causes ''good'' or ''bad'' effects. A negative feedback loop is one that tends to slow down a process, whereas the positive feedback loop tends to accelerate it. The [[mirror neuron]]s are part of a social feedback system, when an observed action is "mirrored" by the brain—like a self-performed action. − − Biological systems contain many types of regulatory circuits, both positive and negative. As in other contexts, positive and negative do not imply that the feedback causes good or bad effects. A negative feedback loop is one that tends to slow down a process, whereas the positive feedback loop tends to accelerate it. The mirror neurons are part of a social feedback system, when an observed action is "mirrored" by the brain—like a self-performed action. − − 生物系统包含许多类型的调节回路，有正回路也有负回路。正如在其他情况下一样，正反馈并不意味着反馈会产生好的或坏的影响。负反馈回路倾向于减慢一个过程，而正反馈回路倾向于加速它。镜像神经元是社会反馈系统的一部分，当观察到的行为被大脑“镜像” ，就像一个自我执行的行为。 − − − − − − Normal tissue integrity is preserved by feedback interactions between diverse cell types mediated by adhesion molecules and secreted molecules that act as mediators; failure of key feedback mechanisms in cancer disrupts tissue function.<ref>{{cite journal|last1=Vlahopoulos|first1=SA|last2=Cen|first2=O|last3=Hengen|first3=N|last4=Agan|first4=J|last5=Moschovi|first5=M|last6=Critselis|first6=E|last7=Adamaki|first7=M|last8=Bacopoulou|first8=F|last9=Copland|first9=JA|last10=Boldogh|first10=I|last11=Karin|first11=M|last12=Chrousos|first12=GP|title=Dynamic aberrant NF-κB spurs tumorigenesis: A new model encompassing the microenvironment.|journal=Cytokine & Growth Factor Reviews|date=20 June 2015|pmid=26119834|doi=10.1016/j.cytogfr.2015.06.001|volume=26|issue=4|pages=389–403|pmc=4526340}}</ref> − − Normal tissue integrity is preserved by feedback interactions between diverse cell types mediated by adhesion molecules and secreted molecules that act as mediators; failure of key feedback mechanisms in cancer disrupts tissue function. − − 正常组织的完整性是通过粘附分子介导的不同类型细胞之间的反馈相互作用和作为介质的分泌分子来保持的; 癌症中关键反馈机制的失败扰乱了组织功能。 − − In an injured or infected tissue, inflammatory mediators elicit feedback responses in cells, which alter gene expression, and change the groups of molecules expressed and secreted, including molecules that induce diverse cells to cooperate and restore tissue structure and function. This type of feedback is important because it enables coordination of immune responses and recovery from infections and injuries. During cancer, key elements of this feedback fail. This disrupts tissue function and immunity.<ref>{{cite journal | last1 = Vlahopoulos | first1 = SA | title = Aberrant control of NF-κB in cancer permits transcriptional and phenotypic plasticity, to curtail dependence on host tissue: molecular mode. | journal = Cancer Biology & Medicine | date = August 2017 | pmid = 28884042 | doi = 10.20892/j.issn.2095-3941.2017.0029 | volume = 14 | issue = 3 | pages = 254–270 | pmc = 5570602}}</ref><ref>{{cite journal|last1=Korneev|first1=KV|last2=Atretkhany|first2=KN|last3=Drutskaya|first3=MS|last4=Grivennikov|first4=SI|last5=Kuprash|first5=DV|last6=Nedospasov|first6=SA|title=TLR-signaling and proinflammatory cytokines as drivers of tumorigenesis.|journal=Cytokine|date=January 2017|volume=89|pages=127–135|doi=10.1016/j.cyto.2016.01.021|pmid=26854213}}</ref> − − In an injured or infected tissue, inflammatory mediators elicit feedback responses in cells, which alter gene expression, and change the groups of molecules expressed and secreted, including molecules that induce diverse cells to cooperate and restore tissue structure and function. This type of feedback is important because it enables coordination of immune responses and recovery from infections and injuries. During cancer, key elements of this feedback fail. This disrupts tissue function and immunity. − − 在受伤或受感染的组织中，炎症介质在细胞中引发反馈反应，改变基因表达，改变表达和分泌的分子群，包括诱导不同细胞合作并恢复组织结构和功能的分子。这种类型的反馈是重要的，因为它能够协调免疫反应和从感染和伤害中恢复。在癌症期间，这种反馈的关键因素失效了。这会破坏组织功能和免疫力。 − − − − − − Mechanisms of feedback were first elucidated in bacteria, where a nutrient elicits changes in some of their metabolic functions.<ref>{{cite journal|last1= Sanwal|first1=BD| title= Allosteric controls of amphilbolic pathways in bacteria.|journal= Bacteriol. Rev.|date=March 1970|volume=34|issue=1|pages=20–39 |pmid=4315011 |pmc=378347|doi=10.1128/MMBR.34.1.20-39.1970}}</ref> − − Mechanisms of feedback were first elucidated in bacteria, where a nutrient elicits changes in some of their metabolic functions. − − 反馈机制首次在细菌中得到阐明，营养物质引起细菌某些代谢功能的变化。 − − Feedback is also central to the operations of [[gene]]s and [[gene regulatory network]]s. [[Repressor protein|Repressor]] (see [[Lac repressor]]) and [[activator protein|activator]] [[protein]]s are used to create genetic [[operon]]s, which were identified by [[Francois Jacob]] and [[Jacques Monod]] in 1961 as ''feedback loops''.<ref>{{cite journal|last1= Jacob|first1=F|last2=Monod|first2=J|title= Genetic regulatory mechanisms in the synthesis of proteins.|journal= J Mol Biol|date=June 1961|volume=3|issue=3|pages=318–356 |pmid=13718526|doi=10.1016/S0022-2836(61)80072-7}}</ref> These feedback loops may be positive (as in the case of the coupling between a sugar molecule and the proteins that import sugar into a bacterial cell), or negative (as is often the case in [[metabolic]] consumption). − − Feedback is also central to the operations of genes and gene regulatory networks. Repressor (see Lac repressor) and activator proteins are used to create genetic operons, which were identified by Francois Jacob and Jacques Monod in 1961 as feedback loops. These feedback loops may be positive (as in the case of the coupling between a sugar molecule and the proteins that import sugar into a bacterial cell), or negative (as is often the case in metabolic consumption). − − 反馈也是基因和基因调控网络运作的中心。阻遏蛋白(参见 Lac 阻遏蛋白)和激活蛋白被用来创造基因操纵子，这被 Francois Jacob 和 Jacques Monod 在1961年确定为反馈回路。这些反馈回路可能是正的(例如糖分子和将糖输入细菌细胞的蛋白质之间的耦合) ，也可能是负的(例如代谢消耗中经常出现的情况)。 − − − − − − On a larger scale, feedback can have a stabilizing effect on animal populations even when profoundly affected by external changes, although time lags in feedback response can give rise to [[Lotka–Volterra equation|predator-prey cycles]].<ref> − − On a larger scale, feedback can have a stabilizing effect on animal populations even when profoundly affected by external changes, although time lags in feedback response can give rise to predator-prey cycles.<ref> − − 在更大的范围内，即使受到外部变化的深刻影响，反馈也能对动物种群产生稳定作用，尽管反馈反应的时间滞后可能导致捕食者-被捕食者循环。 裁判 − − CS Holling. "Resilience and stability of ecological systems". Annual Review of Ecology and Systematics 4:1-23. 1973</ref> − − CS Holling. "Resilience and stability of ecological systems". Annual Review of Ecology and Systematics 4:1-23. 1973</ref> − − Cs Holling.”生态系统的复原力和稳定性”。生态学与系统学年度回顾4:1-23。1973 / ref − − − − − − In [[fermentation (biochemistry)|zymology]], feedback serves as regulation of activity of an enzyme by its direct product(s) or downstream metabolite(s) in the metabolic pathway (see [[Allosteric regulation]]). − − In zymology, feedback serves as regulation of activity of an enzyme by its direct product(s) or downstream metabolite(s) in the metabolic pathway (see Allosteric regulation). − − 在酶学中，反馈是通过酶在代谢途径中的直接产物或下游代谢产物来调节酶的活性(见别构调节)。 − − − − − − The [[hypothalamic–pituitary–adrenal axis]] is largely controlled by positive and negative feedback, much of which is still unknown. − − The hypothalamic–pituitary–adrenal axis is largely controlled by positive and negative feedback, much of which is still unknown. − − 下丘脑-垂体-肾上腺轴在很大程度上受正反馈和负反馈控制，其中大部分尚不清楚。 − − − − − − In [[psychology]], the body receives a stimulus from the environment or internally that causes the release of [[hormone]]s. Release of hormones then may cause more of those hormones to be released, causing a positive feedback loop. This cycle is also found in certain behaviour. For example, "shame loops" occur in people who blush easily. When they realize that they are blushing, they become even more embarrassed, which leads to further blushing, and so on.<ref>{{cite magazine|last=Scheff |first=Thomas |url=http://www.psychologytoday.com/blog/lets-connect/200909/the-emotionalrelational-world |title=The Emotional/Relational World |magazine=Psychology Today |date=2009-09-02 |accessdate=2013-07-10}}</ref> − − In psychology, the body receives a stimulus from the environment or internally that causes the release of hormones. Release of hormones then may cause more of those hormones to be released, causing a positive feedback loop. This cycle is also found in certain behaviour. For example, "shame loops" occur in people who blush easily. When they realize that they are blushing, they become even more embarrassed, which leads to further blushing, and so on. − − 在心理学中，身体受到来自环境或内部的刺激，从而导致荷尔蒙的释放。然后，荷尔蒙的释放可能会导致更多的荷尔蒙被释放，从而形成一个积极的反馈循环。在某些行为中也发现了这种循环。例如，“羞耻循环”发生在容易脸红的人身上。当他们意识到自己脸红时，他们会变得更加尴尬，从而导致进一步脸红，等等。 − − − − − − ===Climate science=== − − ===Climate science=== − − 气候科学 − − {{Main|Climate change feedback}} − − − − − − − − The climate system is characterized by strong positive and negative feedback loops between processes that affect the state of the atmosphere, ocean, and land. A simple example is the [[Ice-albedo feedback|ice-albedo positive feedback]] loop whereby melting snow exposes more dark ground (of lower [[albedo]]), which in turn absorbs heat and causes more snow to melt. − − The climate system is characterized by strong positive and negative feedback loops between processes that affect the state of the atmosphere, ocean, and land. A simple example is the ice-albedo positive feedback loop whereby melting snow exposes more dark ground (of lower albedo), which in turn absorbs heat and causes more snow to melt. − − 气候系统是影响大气、海洋和陆地状态的过程之间强有力的正反馈拥有属性。一个简单的例子是冰反照率正反馈循环，即融化的雪暴露出更多的黑色地面(反照率较低) ，反过来吸收热量，导致更多的雪融化。 − − − − − − ===Control theory=== − − ===Control theory=== − − 控制理论 − − {{Main|Control theory}} − − − − Feedback is extensively used in control theory, using a variety of methods including [[state space (controls)]], [[full state feedback]], and so forth. Note that in the context of control theory, "feedback" is traditionally assumed to specify "negative feedback".<ref name=mees> − − Feedback is extensively used in control theory, using a variety of methods including state space (controls), full state feedback, and so forth. Note that in the context of control theory, "feedback" is traditionally assumed to specify "negative feedback".<ref name=mees> − − 反馈广泛应用于控制理论中，使用了包括状态空间(控件)、全状态反馈等多种方法。注意，在控制理论的背景下，“反馈”通常被假定为指定“负反馈” − − ''"There is a tradition in control theory that one deals with a ''negative feedback loop'' in which a negative sign is included in the feedback loop..."'' − − "There is a tradition in control theory that one deals with a negative feedback loop in which a negative sign is included in the feedback loop..." − − “控制理论有一个传统，即处理负反馈回路，其中负号包含在反馈回路中... ... ” − − A.I.Mees, "Dynamics of Feedback Systems", New York: J. Wiley, c1981. {{ISBN|0-471-27822-X}}. p69</ref> − − A.I.Mees, "Dynamics of Feedback Systems", New York: J. Wiley, c1981. . p69</ref> − − 反馈系统的动力学》 ，纽约: j. Wiley，c1981。.P69 / ref − − {{Further|PID controller}} − − − − The most common general-purpose [[controller (control theory)|controller]] using a control-loop feedback mechanism is a [[PID controller|proportional-integral-derivative]] (PID) controller. Heuristically, the terms of a PID controller can be interpreted as corresponding to time: the proportional term depends on the ''present'' error, the integral term on the accumulation of ''past'' errors, and the derivative term is a prediction of ''future'' error, based on current rate of change.<ref>{{Citation | url = http://www.eolss.net/ebooks/Sample%20Chapters/C18/E6-43-03-03.pdf | title = PID Control | last = Araki | first = M. }}</ref> − − The most common general-purpose controller using a control-loop feedback mechanism is a proportional-integral-derivative (PID) controller. Heuristically, the terms of a PID controller can be interpreted as corresponding to time: the proportional term depends on the present error, the integral term on the accumulation of past errors, and the derivative term is a prediction of future error, based on current rate of change. − − 使用控制回路反馈机制的最常见的通用控制器是比例积分微分(PID)控制器。启发式地，PID 控制器的条款可以解释为对应的时间: 比例项取决于当前的错误，积分项积累过去的错误，导数项是一个预测未来的错误，基于当前的变化率。 − − − − − − ===Mechanical engineering=== − − ===Mechanical engineering=== − − 机械工程 − − In ancient times, the [[float valve]] was used to regulate the flow of water in Greek and Roman [[water clock]]s; similar float valves are used to regulate fuel in a [[carburettor]] and also used to regulate tank water level in the [[flush toilet]]. − − In ancient times, the float valve was used to regulate the flow of water in Greek and Roman water clocks; similar float valves are used to regulate fuel in a carburettor and also used to regulate tank water level in the flush toilet. − − 在古代，浮子阀被用来调节希腊和罗马水钟中的水流; 类似的浮子阀被用来调节化油器中的燃料，也被用来调节抽水马桶中的水位。 − − − − − − The Dutch inventor [[Cornelius Drebbel]] (1572-1633) built thermostats (c1620) to control the temperature of chicken incubators and chemical furnaces. In 1745, the windmill was improved by blacksmith Edmund Lee, who added a [[windmill fantail|fantail]] to keep the face of the windmill pointing into the wind. In 1787, [[Tom Mead]] regulated the rotation speed of a windmill by using a [[conical pendulum|centrifugal pendulum]] to adjust the distance between the bedstone and the runner stone (i.e., to adjust the load). − − The Dutch inventor Cornelius Drebbel (1572-1633) built thermostats (c1620) to control the temperature of chicken incubators and chemical furnaces. In 1745, the windmill was improved by blacksmith Edmund Lee, who added a fantail to keep the face of the windmill pointing into the wind. In 1787, Tom Mead regulated the rotation speed of a windmill by using a centrifugal pendulum to adjust the distance between the bedstone and the runner stone (i.e., to adjust the load). − − 荷兰发明家克尼利厄斯·雅布斯纵·戴博尔(1572-1633)建造了恒温器(c1620)来控制鸡的孵化器和化学炉的温度。1745年，铁匠埃德蒙 · 李对风车进行了改进，他在风车的正面加上了扇尾，使风车面朝向风。1787年，汤姆 · 米德通过使用离心摆来调节底石和流水石之间的距离(即调节负荷)来调节风车的转速。 − − − − − − The use of the [[centrifugal governor]] by [[James Watt]] in 1788 to regulate the speed of his [[steam engine]] was one factor leading to the [[Industrial Revolution]]. Steam engines also use float valves and [[relief valve|pressure release valves]] as mechanical regulation devices. A [[mathematical analysis]] of Watt's governor was done by [[James Clerk Maxwell]] in 1868.<ref name=maxwell/> − − The use of the centrifugal governor by James Watt in 1788 to regulate the speed of his steam engine was one factor leading to the Industrial Revolution. Steam engines also use float valves and pressure release valves as mechanical regulation devices. A mathematical analysis of Watt's governor was done by James Clerk Maxwell in 1868. − − 1788年 James Watt 使用离心式调速器来调节他的蒸汽机的速度是导致工业革命的一个因素。蒸汽发动机也使用浮子阀和释压阀作为机械调节装置。詹姆斯·克拉克·麦克斯韦在1868年对瓦特的调节器进行了数学分析。 − − − − − − The ''[[SS Great Eastern|Great Eastern]]'' was one of the largest steamships of its time and employed a steam powered rudder with feedback mechanism designed in 1866 by [[John McFarlane Gray]]. [[Joseph Farcot]] coined the word ''[[Servomechanism|servo]]'' in 1873 to describe steam-powered steering systems. Hydraulic servos were later used to position guns. [[Elmer Ambrose Sperry]] of the [[Sperry Corporation]] designed the first [[autopilot]] in 1912. [[Nicolas Minorsky]] published a theoretical analysis of automatic ship steering in 1922 and described the [[PID controller]].<ref name="Minorsky">{{cite journal |author=Minorsky, Nicolas |year=1922 |title=Directional stability of automatically steered bodies |journal=J. Amer. Soc of Naval Engineers |volume=34 |issue= 2|pages=280–309 |doi= 10.1111/j.1559-3584.1922.tb04958.x|pmid= |pmc= |url= |accessdate= }}</ref> − − The Great Eastern was one of the largest steamships of its time and employed a steam powered rudder with feedback mechanism designed in 1866 by John McFarlane Gray. Joseph Farcot coined the word servo in 1873 to describe steam-powered steering systems. Hydraulic servos were later used to position guns. Elmer Ambrose Sperry of the Sperry Corporation designed the first autopilot in 1912. Nicolas Minorsky published a theoretical analysis of automatic ship steering in 1922 and described the PID controller. − − 大东方号是当时最大的轮船之一，在1866年由约翰 · 麦克法兰 · 格雷设计了带有反馈机制的蒸汽动力舵。约瑟夫 · 法科特在1873年创造了“伺服”这个词来描述蒸汽动力转向系统。液压伺服系统后来被用来定位枪支。史派里公司的 Elmer Ambrose Sperry 在1912年设计了第一个自动驾驶仪。尼古拉斯·米诺尔斯基在1922年发表了一篇关于船舶自动操舵的理论分析，并描述了 PID 控制器。 − − − − − − Internal combustion engines of the late 20th century employed mechanical feedback mechanisms such as the [[Ignition timing#Vacuum timing advance|vacuum timing advance]] but mechanical feedback was replaced by electronic [[engine control unit|engine management systems]] once small, robust and powerful single-chip [[microcontroller]]s became affordable. − − Internal combustion engines of the late 20th century employed mechanical feedback mechanisms such as the vacuum timing advance but mechanical feedback was replaced by electronic engine management systems once small, robust and powerful single-chip microcontrollers became affordable. − − 20世纪后期的内燃机采用了机械反馈机制，如真空定时推进，但机械反馈被电子发动机管理系统所取代，一旦小型、强大和功能强大的单片微控制器变得可以负担得起。 − − − − − − ===Electronic engineering=== − − ===Electronic engineering=== − − 电子工程 − − [[File:Ideal feedback model.svg|thumb|The simplest form of a feedback amplifier can be represented by the ''ideal block diagram'' made up of [https://www.google.com/search?tbo=p&tbm=bks&q=%22A+unilateral+block+or+network+is+one+in+which+power+may+be+transmitted+in+one+direction+only.%22&num=10&gws_rd=ssl unilateral elements].<ref name="Chen"> − − [[File:Ideal feedback model.svg|thumb|The simplest form of a feedback amplifier can be represented by the ideal block diagram made up of [https://www.google.com/search?tbo=p&tbm=bks&q=%22A+unilateral+block+or+network+is+one+in+which+power+may+be+transmitted+in+one+direction+only.%22&num=10&gws_rd=ssl unilateral elements].<ref name="Chen"> − − 理想的反馈模型.svg | thumb | 反馈放大器最简单的形式可以用理想的方框图来表示，理想的方框图是由 https://www.google.com/search?tbo=p&tbm=bks&q=%22a+unilateral+block+or+network+is+one+in+which+power+may+be+transmitted+in+one+direction+only.%22&num=10&gws_rd=ssl 单边元素组成的 . ref name“ Ch − − {{cite book|title=Circuit Analysis and Feedback Amplifier Theory|author=Wai-Kai Chen|publisher=CRC Press|year=2005|isbn=9781420037272|location=423825181|pages=13–1|chapter=Chapter 13: General feedback theory|quote=[In a practical amplifier] the forward path may not be strictly unilateral, the feedback path is usually bilateral, and the input and output coupling networks are often complicated.|chapter-url=https://books.google.com/books?id=ZlJM1OLDQx0C&pg=SA13-PA1}} − − − − </ref>|280px|right]] − − </ref>|280px|right]] − − 280px | right ] − − − − − − The use of feedback is widespread in the design of [[electronics|electronic]] components such as [[amplifier]]s, [[oscillator]]s, and stateful [[logic circuit]] elements such as [[flip-flop (electronics)|flip-flop]]s and [[counter (digital)|counter]]s. Electronic feedback systems are also very commonly used to control mechanical, thermal and other physical processes. − − The use of feedback is widespread in the design of electronic components such as amplifiers, oscillators, and stateful logic circuit elements such as flip-flops and counters. Electronic feedback systems are also very commonly used to control mechanical, thermal and other physical processes. − − 在电子元件的设计中，反馈的应用非常广泛，例如放大器、振荡器和有状态逻辑电路元件，例如触发器和计数器。电子反馈系统也非常常用于控制机械，热和其他物理过程。 − − − − − − If the signal is inverted on its way round the control loop, the system is said to have ''[[negative feedback amplifier|negative feedback]]'';<ref name=KalS> − − If the signal is inverted on its way round the control loop, the system is said to have negative feedback;<ref name=KalS> − − 如果在控制回路中信号是倒置的，那么系统就是负反馈; ref name kals − − {{cite book |title=Basic Electronics: Devices, Circuits and IT Fundamentals |author=Santiram Kal |url=https://books.google.com/?id=_Bw_-ZyGL6YC&pg=PA191&dq=%22it+is+called+negative+feedback%22+%22if+the+feedback+signal+reduces+the+input+signal%22#v=onepage&q=%22it%20is%20called%20negative%20feedback%22%20%22if%20the%20feedback%20signal%20reduces%20the%20input%20signal%22&f=false |quote=If the feedback signal reduces the input signal, ''i.e.'' it is out of phase with the input [signal], it is called negative feedback. |isbn=9788120319523 |year=2009 |publisher=PHI Learning Pvt. Ltd |page=191}} − − − − </ref> otherwise, the feedback is said to be ''positive''. Negative feedback is often deliberately introduced to increase the [[BIBO stability|stability]] and accuracy of a system by correcting or reducing the influence of unwanted changes. This scheme can fail if the input changes faster than the system can respond to it. When this happens, the lag in arrival of the correcting signal can result in over-correction, causing the output to [[oscillation|oscillate]] or "hunt".<ref>With mechanical devices, hunting can be severe enough to destroy the device.</ref> While often an unwanted consequence of system behaviour, this effect is used deliberately in electronic oscillators. − − </ref> otherwise, the feedback is said to be positive. Negative feedback is often deliberately introduced to increase the stability and accuracy of a system by correcting or reducing the influence of unwanted changes. This scheme can fail if the input changes faster than the system can respond to it. When this happens, the lag in arrival of the correcting signal can result in over-correction, causing the output to oscillate or "hunt". While often an unwanted consequence of system behaviour, this effect is used deliberately in electronic oscillators. − − 否则，反馈是正面的。负反馈通常是有意引入的，通过纠正或减少不必要的变化的影响来提高系统的稳定性和准确性。如果输入变化快于系统的响应速度，则此方案可能失败。当这种情况发生时，校正信号到达的滞后可能导致过度校正，导致输出振荡或“捕获”。虽然这种效应通常是系统行为的一个不希望出现的结果，但它却被有意地用于电子振荡器中。 − − − − − − [[Harry Nyquist]] at [[Bell Labs]] derived the [[Nyquist stability criterion]] for determining the stability of feedback systems. An easier method, but less general, is to use [[Bode plot]]s developed by [[Hendrik Wade Bode|Hendrik Bode]] to determine the [[Gain margin|gain margin and phase margin]]. Design to ensure stability often involves [[frequency compensation]] to control the location of the [[pole (complex analysis)|pole]]s of the amplifier. − − Harry Nyquist at Bell Labs derived the Nyquist stability criterion for determining the stability of feedback systems. An easier method, but less general, is to use Bode plots developed by Hendrik Bode to determine the gain margin and phase margin. Design to ensure stability often involves frequency compensation to control the location of the poles of the amplifier. − − 贝尔实验室的 Harry Nyquist 推导出了确定反馈系统稳定性的奈奎斯特稳定判据。一个比较简单但不太普遍的方法是使用 hendrikbode 开发的 Bode 图来确定增益裕度和相位裕度。保证稳定性的设计往往涉及频率补偿来控制放大器的极点位置。 − − − − − − Electronic feedback loops are used to control the output of [[electronics|electronic]] devices, such as [[amplifiers]]. A feedback loop is created when all or some portion of the output is fed back to the input. A device is said to be operating ''open loop'' if no output feedback is being employed and ''closed loop'' if feedback is being used.<ref>P. Horowitz & W. Hill, ''The Art of Electronics'', Cambridge University Press (1980), Chapter 3, relating to operational amplifiers.</ref> − − Electronic feedback loops are used to control the output of electronic devices, such as amplifiers. A feedback loop is created when all or some portion of the output is fed back to the input. A device is said to be operating open loop if no output feedback is being employed and closed loop if feedback is being used. − − 电子反馈回路用于控制放大器等电子设备的输出。当输出的全部或部分被反馈给输入时，就创建了一个反馈循环。如果没有采用输出反馈，则称装置为操作开环，如果采用反馈，则称装置为闭环。 − − − − − − When two or more amplifiers are cross-coupled using positive feedback, complex behaviors can be created. These ''[[multivibrator]]s'' are widely used and include: − − When two or more amplifiers are cross-coupled using positive feedback, complex behaviors can be created. These multivibrators are widely used and include: − − 当两个或两个以上的放大器使用正反馈进行交叉耦合时，可以产生复杂的行为。这些多重振动器被广泛使用，包括: − − − − − − * astable circuits, which act as oscillators − − − − * monostable circuits, which can be pushed into a state, and will return to the stable state after some time − − − − * bistable circuits, which have two stable states that the circuit can be switched between − − − − − − − − ====Negative feedback==== − − ====Negative feedback==== − − 负面反馈 − − A Negative feedback occurs when the fed-back output signal has a relative phase of 180° with respect to the input signal (upside down). This situation is sometimes referred to as being ''out of phase'', but that term also is used to indicate other phase separations, as in "90° out of phase". Negative feedback can be used to correct output errors or to desensitize a system to unwanted fluctuations.<ref name=Bhattacharya> − − A Negative feedback occurs when the fed-back output signal has a relative phase of 180° with respect to the input signal (upside down). This situation is sometimes referred to as being out of phase, but that term also is used to indicate other phase separations, as in "90° out of phase". Negative feedback can be used to correct output errors or to desensitize a system to unwanted fluctuations.<ref name=Bhattacharya> − − 当反馈输出信号相对于输入信号的相位为180时，就会出现负反馈。这种情况有时被称为不同相，但这个术语也用来表示其他相分离，如“90不同相”。负反馈可以用来纠正输出错误或者使系统对有害的波动不敏感 − − For an analysis of desensitization in the system pictured, see {{cite book |author=S.K Bhattacharya |title=Linear Control Systems |pages=134–135 |quote=The parameters of a system ... may vary... The primary advantage of using feedback in control systems is to reduce the system's sensitivity to parameter variations. |chapter=§5.3.1 Effect of feedback on parameter variations |isbn=9788131759523 |publisher=Pearson Education India |year=2011 |chapter-url=https://books.google.com/books?id=e5Z1A_6jxAUC&pg=PA135&dq=%22primary+advantage+of+using+feedback+in+control+system+is+to+reduce+the+system%27s+sensitivity+to+parameter+variations%22&hl=en&sa=X&ei=BbX8U_zpMIKcjAKklYGoDQ&ved=0CB0Q6AEwAA#v=onepage&q=%22primary%20advantage%20of%20using%20feedback%20in%20control%20system%20is%20to%20reduce%20the%20system%27s%20sensitivity%20to%20parameter%20variations%22&f=false}} − − For an analysis of desensitization in the system pictured, see − − 有关图中系统脱敏的分析，请参阅 − − </ref> In feedback amplifiers, this correction is generally for waveform [[distortion]] reduction{{citation needed|date=October 2014}} or to establish a specified [[Gain (electronics)|gain]] level. A general expression for the gain of a negative feedback amplifier is the [[asymptotic gain model]]. − − </ref> In feedback amplifiers, this correction is generally for waveform distortion reduction or to establish a specified gain level. A general expression for the gain of a negative feedback amplifier is the asymptotic gain model. − − 在反馈放大器中，这种校正通常用于降低波形失真或建立指定的增益电平。获得负反馈放大器的一个通用表达式是渐进增益模型。 − − − − − − ====Positive feedback==== − − ====Positive feedback==== − − 积极的反馈 − − Positive feedback occurs when the fed-back signal is in phase with the input signal. Under certain gain conditions, positive feedback reinforces the input signal to the point where the output of the device [[oscillates]] between its maximum and minimum possible states. Positive feedback may also introduce [[hysteresis]] into a circuit. This can cause the circuit to ignore small signals and respond only to large ones. It is sometimes used to eliminate noise from a digital signal. Under some circumstances, positive feedback may cause a device to latch, i.e., to reach a condition in which the output is locked to its maximum or minimum state. This fact is very widely used in digital electronics to make [[Flip-flop (electronics)|bistable]] circuits for volatile storage of information. − − Positive feedback occurs when the fed-back signal is in phase with the input signal. Under certain gain conditions, positive feedback reinforces the input signal to the point where the output of the device oscillates between its maximum and minimum possible states. Positive feedback may also introduce hysteresis into a circuit. This can cause the circuit to ignore small signals and respond only to large ones. It is sometimes used to eliminate noise from a digital signal. Under some circumstances, positive feedback may cause a device to latch, i.e., to reach a condition in which the output is locked to its maximum or minimum state. This fact is very widely used in digital electronics to make bistable circuits for volatile storage of information. − − 当反馈信号与输入信号同相时，就会产生正反馈。在一定的增益条件下，正反馈增强输入信号，使器件的输出在其最大和最小可能状态之间振荡。正反馈也可能在电路中引入滞后。这会导致电路忽略小信号，只响应大信号。它有时被用来消除数字信号中的噪声。在某些情况下，正反馈可能导致设备闭锁，即，达到输出锁定到其最大或最小状态的条件。这一事实在数字电子产品中被广泛应用，用于制造信息挥发性记忆体的双稳态电路。 − − − − − − The loud squeals that sometimes occurs in [[audio system]]s, [[public address system|PA systems]], and [[rock music]] are known as [[audio feedback]]. If a microphone is in front of a loudspeaker that it is connected to, sound that the microphone picks up comes out of the speaker, and is picked up by the microphone and re-amplified. If the [[loop gain]] is sufficient, howling or squealing at the maximum power of the amplifier is possible. − − The loud squeals that sometimes occurs in audio systems, PA systems, and rock music are known as audio feedback. If a microphone is in front of a loudspeaker that it is connected to, sound that the microphone picks up comes out of the speaker, and is picked up by the microphone and re-amplified. If the loop gain is sufficient, howling or squealing at the maximum power of the amplifier is possible. − − 有时在音频系统、扩音系统和摇滚乐中发出的响亮的尖叫声被称为音频反馈。如果麦克风位于与之相连的扬声器前面，麦克风拾取的声音就会从扬声器中发出，然后被麦克风拾取并重新放大。如果环路增益是足够的，嚎叫或尖叫在最大功率的放大器是可能的。 − − − − − − ====Oscillator==== − − ====Oscillator==== − − 振荡器 − − [[File:OpAmpHystereticOscillator.svg|thumb|A popular [[Relaxation oscillator#Comparator–based electronic relaxation oscillator|op-amp relaxation oscillator]].]] − − op-amp relaxation oscillator.]] − − [运放张弛振荡器] − − An [[electronic oscillator]] is an [[electronic circuit]] that produces a periodic, [[oscillation|oscillating]] electronic signal, often a [[sine wave]] or a [[square wave]].<ref name="Snelgrove">{{cite web − − An electronic oscillator is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave.<ref name="Snelgrove">{{cite web − − 振盪器是一种产生周期性振荡电子信号的电子电路，通常是正弦波或方波。 这个网站名为"snelgrove"{ cite web − − | last = Snelgrove − − | last = Snelgrove − − 最后的斯内尔格罗夫 − − | first = Martin − − | first = Martin − − 首先是马丁 − − | title = Oscillator − − | title = Oscillator − − | 标题振荡器 − − | encyclopedia = McGraw-Hill Encyclopedia of Science and Technology, 10th Ed., Science Access online service − − | encyclopedia = McGraw-Hill Encyclopedia of Science and Technology, 10th Ed., Science Access online service − − 百科全书麦格劳-希尔科学与技术百科全书，第10版，科学访问在线服务 − − | publisher = McGraw-Hill − − | publisher = McGraw-Hill − − | 出版商麦格劳-希尔 − − | year = 2011 − − | year = 2011 − − 2011年 − − | url = http://accessscience.com/abstract.aspx?id=477900&referURL=http%3a%2f%2faccessscience.com%2fcontent.aspx%3fid%3d477900 − − | url = http://accessscience.com/abstract.aspx?id=477900&referURL=http%3a%2f%2faccessscience.com%2fcontent.aspx%3fid%3d477900 − − Http://accessscience.com/abstract.aspx?id=477900&referurl=http%3a%2f%2faccessscience.com%2fcontent.aspx%3fid%3d477900 − − | format = − − | format = − − 格式 − − | doi = − − | doi = − − 不会吧 − − | access-date = 1 March 2012 − − | access-date = 1 March 2012 − − | 2012年3月1日 − − | archive-url = https://web.archive.org/web/20130719125711/http://accessscience.com/abstract.aspx?id=477900&referURL=http%3A%2F%2Faccessscience.com%2Fcontent.aspx%3Fid%3D477900 − − | archive-url = https://web.archive.org/web/20130719125711/http://accessscience.com/abstract.aspx?id=477900&referURL=http%3A%2F%2Faccessscience.com%2Fcontent.aspx%3Fid%3D477900 − − | 档案-网址 https://web.archive.org/web/20130719125711/http://accessscience.com/abstract.aspx?id=477900&referurl=http%3a%2f%2faccessscience.com%2fcontent.aspx%3fid%3d477900 − − | archive-date = 19 July 2013 − − | archive-date = 19 July 2013 − − | 档案-日期2013年7月19日 − − | url-status = dead − − | url-status = dead − − 状态死机 − − }}</ref><ref name="Chattopadhyay">{{cite book − − }}</ref><ref name="Chattopadhyay">{{cite book − − {} / ref name"chattopadhyay"{ cite book − − | last = Chattopadhyay − − | last = Chattopadhyay − − | last = Chattopadhyay − − | first = D. − − | first = D. − − 第一个 d。 − − | title = Electronics (fundamentals And Applications) − − | title = Electronics (fundamentals And Applications) − − | 题目: 电子学(基础与应用) − − | publisher = New Age International − − | publisher = New Age International − − | 出版商 New Age International − − | year = 2006 − − | year = 2006 − − 2006年 − − | location = − − | location = − − | 位置 − − | pages = 224–225 − − | pages = 224–225 − − 第224-225页 − − | url = https://books.google.com/?id=n0rf9_2ckeYC&pg=PA224&dq=%22negative+resistance%22#v=onepage&q=%22negative%20resistance%22&f=false − − | url = https://books.google.com/?id=n0rf9_2ckeYC&pg=PA224&dq=%22negative+resistance%22#v=onepage&q=%22negative%20resistance%22&f=false − − Https://books.google.com/?id=n0rf9_2ckeyc&pg=pa224&dq=%22negative+resistance%22#v=onepage&q=%22negative%20resistance%22&f=false − − | doi = − − | doi = − − 不会吧 − − | id = − − | id = − − 我会的 − − | isbn = 978-81-224-1780-7}}</ref> Oscillators convert [[direct current]] (DC) from a power supply to an [[alternating current]] signal. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by [[Radio transmitter|radio]] and [[television transmitter]]s, clock signals that regulate computers and [[quartz clock]]s, and the sounds produced by electronic beepers and [[video game]]s.<ref name="Snelgrove" /> − − | isbn = 978-81-224-1780-7}}</ref> Oscillators convert direct current (DC) from a power supply to an alternating current signal. They are widely used in many electronic devices. Common examples of signals generated by oscillators include signals broadcast by radio and television transmitters, clock signals that regulate computers and quartz clocks, and the sounds produced by electronic beepers and video games. − − | isbn 978-81-224-1780-7} / ref 振荡器将直流电从电源转换为交流电信号。它们被广泛应用于许多电子设备中。由振荡器产生的信号的常见例子包括由无线电和电视发射机发出的信号、调节计算机和石英钟的时钟信号，以及电子寻呼机和电子游戏产生的声音。 − − − − − − Oscillators are often characterized by the [[frequency]] of their output signal: − − Oscillators are often characterized by the frequency of their output signal: − − 振荡器的输出信号的频率通常是拥有属性的: − − − − − − * A [[low frequency oscillation|low-frequency oscillator]] (LFO) is an electronic oscillator that generates a frequency below ≈20 Hz. This term is typically used in the field of audio [[synthesizers]], to distinguish it from an audio frequency oscillator. − − − − * An audio oscillator<!--Please don't link - circular reference--> produces frequencies in the [[audio frequency|audio]] range, about 16 Hz to 20 kHz.<ref name="Chattopadhyay" /> − − − − * An RF oscillator produces signals in the [[radio frequency]] (RF) range of about 100 kHz to 100 GHz.<ref name="Chattopadhyay" /> − − − − − − − − Oscillators designed to produce a high-power AC output from a DC supply are usually called [[Inverter (electrical)|inverters]]. − − Oscillators designed to produce a high-power AC output from a DC supply are usually called inverters. − − 为从直流电源产生大功率交流输出而设计的振荡器通常称为逆变器。 − − − − − − There are two main types of electronic oscillator: the linear or harmonic oscillator and the nonlinear or [[relaxation oscillator]].<ref name="Chattopadhyay" /><ref name="Garg">{{cite book − − There are two main types of electronic oscillator: the linear or harmonic oscillator and the nonlinear or relaxation oscillator.<ref name="Garg">{{cite book − − 振盪器有两种主要类型: 线性的或谐振子的和非线性的或张弛振荡器的。 文件名“ garg”{ cite book − − | last = Garg − − | last = Garg − − 最后的加格 − − | first = Rakesh Kumar − − | first = Rakesh Kumar − − 首先是拉凯什 · 库马尔 − − | authorlink = − − | authorlink = − − 作者链接 − − | author2=Ashish Dixit |author3=Pavan Yadav − − | author2=Ashish Dixit |author3=Pavan Yadav − − 2 Ashish Dixit | author3 Pavan Yadav − − | title = Basic Electronics − − | title = Basic Electronics − − 基础电子学 − − | publisher = Firewall Media − − | publisher = Firewall Media − − | publisher Firewall Media − − | year = 2008 − − | year = 2008 − − 2008年 − − | location = − − | location = − − | 位置 − − | pages = 280 − − | pages = 280 − − 第280页 − − | url = https://books.google.com/books?id=9SOdnsHA2IYC&pg=PA280&lpg=PA280 − − | url = https://books.google.com/books?id=9SOdnsHA2IYC&pg=PA280&lpg=PA280 − − Https://books.google.com/books?id=9sodnsha2iyc&pg=pa280&lpg=pa280 − − | doi = − − | doi = − − 不会吧 − − | id = − − | id = − − 我会的 − − | isbn = 978-8131803028}}</ref> − − | isbn = 978-8131803028}}</ref> − − [参考文献] − − − − − − ====Latches and flip-flops==== − − ====Latches and flip-flops==== − − 插销和人字拖 − − [[File:JohnsonCounter2.png|thumb|border|A 4-bit [[ring counter]] using [[Flip-flop (electronics)#D flip-flop|D-type flip flops]]]] − − A 4-bit [[ring counter using D-type flip flops]] − − 4位[使用 d 型触发器的环形计数器] − − − − − − A latch or a [[Flip-flop (electronics)|flip-flop]] is a [[electronic circuit|circuit]] that has two stable states and can be used to store state information. They typically constructed using feedback that crosses over between two arms of the circuit, to provide the circuit with a state. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in [[sequential logic]]. Latches and flip-flops are fundamental building blocks of [[digital electronics]] systems used in computers, communications, and many other types of systems. − − A latch or a flip-flop is a circuit that has two stable states and can be used to store state information. They typically constructed using feedback that crosses over between two arms of the circuit, to provide the circuit with a state. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in sequential logic. Latches and flip-flops are fundamental building blocks of digital electronics systems used in computers, communications, and many other types of systems. − − 锁存器或触发器是具有两个稳定状态的电路，可用于存储状态信息。它们通常利用电路的两个臂之间交叉的反馈来构造，以便为电路提供一个状态。该电路可以通过施加到一个或多个控制输入的信号来改变状态，并且具有一个或两个输出。它是时序逻辑电路的基本存储元素。锁存器和触发器是用于计算机、通信和许多其他类型系统的数字电子系统的基本构件。 − − − − − − Latches and flip-flops are used as data storage elements. Such data storage can be used for storage of ''[[state (computer science)|state]]'', and such a circuit is described as [[sequential logic]]. When used in a [[finite-state machine]], the output and next state depend not only on its current input, but also on its current state (and hence, previous inputs). It can also be used for counting of pulses, and for synchronizing variably-timed input signals to some reference timing signal. − − Latches and flip-flops are used as data storage elements. Such data storage can be used for storage of state, and such a circuit is described as sequential logic. When used in a finite-state machine, the output and next state depend not only on its current input, but also on its current state (and hence, previous inputs). It can also be used for counting of pulses, and for synchronizing variably-timed input signals to some reference timing signal. − − 锁存器和触发器用作数据存储元件。这样的数据存储可以用来存储状态，这样的电路被描述为时序逻辑电路。在有限状态机中使用时，输出和下一状态不仅取决于其当前输入，还取决于其当前状态(因此，以前的输入)。它也可以用于计数脉冲，并用于同步一些参考定时信号的变时输入信号。 − − − − − − Flip-flops can be either simple (transparent or opaque) or [[clock signal|clock]]ed (synchronous or edge-triggered). Although the term flip-flop has historically referred generically to both simple and clocked circuits, in modern usage it is common to reserve the term ''flip-flop'' exclusively for discussing clocked circuits; the simple ones are commonly called ''latches''.<ref name="pedroni"> − − Flip-flops can be either simple (transparent or opaque) or clocked (synchronous or edge-triggered). Although the term flip-flop has historically referred generically to both simple and clocked circuits, in modern usage it is common to reserve the term flip-flop exclusively for discussing clocked circuits; the simple ones are commonly called latches.<ref name="pedroni"> − − 触发器可以是简单(透明或不透明)或计时(同步或边缘触发)。虽然触发器这个术语在历史上一直泛指简单电路和时钟电路，但在现代用法中，通常将触发器这个术语专门用于讨论时钟电路，简单的电路通常称为锁存电路。 裁判员名字“ pedroni” − − {{cite book| author = Volnei A. Pedroni| title = Digital electronics and design with VHDL| url = https://books.google.com/?id=-ZAccwyQeXMC| year = 2008| publisher = Morgan Kaufmann| isbn = 978-0-12-374270-4| page = 329 }}</ref><ref name="ee42">[http://rfic.eecs.berkeley.edu/ee100/pdf/lect24.pdf Latches and Flip Flops] (EE 42/100 Lecture 24 from Berkeley) ''"...Sometimes the terms flip-flop and latch are used interchangeably..."''</ref> − − </ref> − − / 参考 − − − − − − Using this terminology, a latch is level-sensitive, whereas a flip-flop is edge-sensitive. That is, when a latch is enabled it becomes transparent, while a flip flop's output only changes on a single type (positive going or negative going) of clock edge. − − Using this terminology, a latch is level-sensitive, whereas a flip-flop is edge-sensitive. That is, when a latch is enabled it becomes transparent, while a flip flop's output only changes on a single type (positive going or negative going) of clock edge. − − 使用这个术语，锁存器是电平敏感的，而触发器是边缘敏感的。也就是说，当锁存器启用时，它变得透明，而触发器的输出只在时钟边缘的单一类型(正向或负向)上发生变化。 − − − − − − ===Software=== − − ===Software=== − − 软件 − − Feedback loops provide generic mechanisms for controlling the running, maintenance, and evolution of software and computing systems.<ref name="Giese-at-al-engineering-saso-systems"> − − Feedback loops provide generic mechanisms for controlling the running, maintenance, and evolution of software and computing systems.<ref name="Giese-at-al-engineering-saso-systems"> − − 反馈回路提供了控制软件和计算系统的运行、维护和进化的通用机制 − − {{Cite news − − {{Cite news − − {引用新闻 − − |author1=H. Giese |author2=Y. Brun |author3=J. D. M. Serugendo |author4=C. Gacek |author5=H. Kienle |author6=H. Müller |author7=M. Pezzè |author8=M. Shaw |title=Engineering self-adaptive and self-managing systems − − |author1=H. Giese |author2=Y. Brun |author3=J. D. M. Serugendo |author4=C. Gacek |author5=H. Kienle |author6=H. Müller |author7=M. Pezzè |author8=M. Shaw |title=Engineering self-adaptive and self-managing systems − − 1 h.2 y.3 j.D. m. Serugendo | author4 c.5 h.6 h.7 m.8 m.工程自适应和自我管理系统 − − |year= 2009 − − |year= 2009 − − 2009年 − − |publisher=Springer-Verlag − − |publisher=Springer-Verlag − − | 出版商 Springer-Verlag − − }}</ref> Feedback-loops are important models in the engineering of adaptive software, as they define the behaviour of the interactions among the control elements over the adaptation process, to guarantee system properties at run-time. Feedback loops and foundations of control theory have been successfully applied to computing systems.<ref name=Hellerstein-feedbackloop-book> − − }}</ref> Feedback-loops are important models in the engineering of adaptive software, as they define the behaviour of the interactions among the control elements over the adaptation process, to guarantee system properties at run-time. Feedback loops and foundations of control theory have been successfully applied to computing systems.<ref name=Hellerstein-feedbackloop-book> − − } / ref 反馈回路是自适应软件工程中的重要模型，它们定义了自适应过程中控制元素之间相互作用的行为，以保证系统在运行时的性能。反馈环路和控制理论的基础已成功地应用于计算系统 − − {{Cite book − − {{Cite book − − {引用书 − − |author1=J. L. Hellerstein |author2=Y. Diao |author3=S. Parekh |author4=D. M. Tilbury |title=Feedback Control of Computing Systems − − |author1=J. L. Hellerstein |author2=Y. Diao |author3=S. Parekh |author4=D. M. Tilbury |title=Feedback Control of Computing Systems − − 1 j.L. Hellerstein | author2 y.3 s.4 d.计算系统的反馈控制 − − |year= 2004 − − |year= 2004 − − 2004年 − − |publisher=John Wiley & Sons − − |publisher=John Wiley & Sons − − 出版商约翰威立 − − }} − − }} − − }} − − </ref> In particular, they have been applied to the development of products such as [[IBM DB2|IBM's Universal Database server]] and [[IBM Tivoli]]. From a software perspective, the [[autonomic computing|autonomic]] (MAPE, monitor analyze plan execute) loop proposed by researchers of IBM is another valuable contribution to the application of feedback loops to the control of dynamic properties and the design and evolution of autonomic software systems.<ref name="muller-autonomic-computing"> − − </ref> In particular, they have been applied to the development of products such as IBM's Universal Database server and IBM Tivoli. From a software perspective, the autonomic (MAPE, monitor analyze plan execute) loop proposed by researchers of IBM is another valuable contribution to the application of feedback loops to the control of dynamic properties and the design and evolution of autonomic software systems.<ref name="muller-autonomic-computing"> − − 特别是，它们已经应用于 IBM 的通用数据库服务器和 IBM Tivoli 等产品的开发。从软件的角度来看，IBM 研究人员提出的自主(MAPE，monitor analyze plan execute)回路是对反馈回路应用于动态特性控制以及自主软件系统设计和演化的另一个有价值的贡献。 自主计算系统” − − {{Cite news − − {{Cite news − − {引用新闻 − − |author1=J. O. Kephart |author2=D. M. Chess |title=The vision of autonomic computing − − |author1=J. O. Kephart |author2=D. M. Chess |title=The vision of autonomic computing − − 1 j.2 d.国际象棋 | 标题: 自主计算的愿景 − − |year= 2003 − − |year= 2003 − − 2003年 − − }}</ref><ref name="autonomic-computing"> − − }}</ref><ref name="autonomic-computing"> − − } / ref name"autonomic-computing" − − {{Cite news − − {{Cite news − − {引用新闻 − − |author1=H. A. Müller |author2=H. M. Kienle |author3=U. Stege |last-author-amp=yes |title=Autonomic computing: Now you see it, now you don't—design and evolution of autonomic software systems − − |author1=H. A. Müller |author2=H. M. Kienle |author3=U. Stege |last-author-amp=yes |title=Autonomic computing: Now you see it, now you don't—design and evolution of autonomic software systems − − 1 h.A.M. ller | author2 h.作者: m. Kienle。Stege | last-author-amp yes | title Autonomic computing: 现在您看到了，现在您没有ーー设计和演化自主软件系统 − − |year= 2009 − − |year= 2009 − − 2009年 − − }}</ref> − − }}</ref> − − {} / ref − − − − − − ====User interface design==== − − ====User interface design==== − − 用户界面设计 − − {{Main|User interface design}} − − − − − − − − Feedback is also a useful design principle for designing [[user interface]]s. − − Feedback is also a useful design principle for designing user interfaces. − − 反馈也是设计用户界面的一个有用的设计原则。 − − − − − − ===Video feedback=== − − ===Video feedback=== − − 视频反馈 − − [[Video feedback]] is the [[video]] equivalent of [[acoustic feedback]]. It involves a loop between a [[video camera]] input and a video output, e.g., a [[Television|television screen]] or [[video monitor|monitor]]. Aiming the camera at the display produces a complex video image based on the feedback.<ref name=hofstadter>{{cite book|last=Hofstadter|first=Douglas|title=I Am a Strange loop|url=https://archive.org/details/iamstrangeloop00hofs|url-access=registration|year=2007|publisher=Basic Books|location=New York|isbn=978-0-465-03079-8|page=[https://archive.org/details/iamstrangeloop00hofs/page/67 67]}}</ref> − − Video feedback is the video equivalent of acoustic feedback. It involves a loop between a video camera input and a video output, e.g., a television screen or monitor. Aiming the camera at the display produces a complex video image based on the feedback. − − 视频反馈是视频等效的声学反馈。它涉及一个循环之间的视频摄像机输入和视频输出，例如，一个电视屏幕或显示器。将摄像机对准显示器，根据反馈信息生成复杂的视频图像。 − − − − − − ===Social sciences<!--linked from 'Double hermeneutic'-->=== − − ===Social sciences<!--linked from 'Double hermeneutic'-->=== − − 社会科学! ——与“双重解释学”相联系 − − {{For|"feedback" in a performance or educational context|performance appraisal|corrective feedback}} − − − − − − − − ====Economics and finance==== − − ====Economics and finance==== − − 经济和金融 − − The [[stock market]] is an example of a [[system]] prone to oscillatory "hunting", governed by positive and negative feedback resulting from [[Behavioural economics|cognitive and emotional factors]] among market participants. For example: − − The stock market is an example of a system prone to oscillatory "hunting", governed by positive and negative feedback resulting from cognitive and emotional factors among market participants. For example: − − 股票市场就是这样一个系统的例子，它倾向于振荡的”捕猎” ，由市场参与者的认知和情感因素所产生的正反馈和负反馈来控制。例如: − − − − − − * When stocks are rising (a [[bull market]]), the belief that further rises are probable gives investors an incentive to buy (positive feedback—reinforcing the rise, see also [[stock market bubble]] and [[momentum investing]]); but the increased price of the [[stock|shares]], and the [[knowledge]] that there must be a peak after which the market falls, ends up deterring buyers (negative feedback—stabilizing the rise). − − − − * Once the market begins to fall regularly (a [[bear market]]), some investors may expect further losing days and refrain from buying (positive feedback—reinforcing the fall), but others may buy because stocks become more and more of a bargain (negative feedback—stabilizing the fall, see also [[contrarian investing]]). − − − − − − − − [[George Soros]] used the word ''[[Reflexivity (social theory)|reflexivity]],'' to describe feedback in the financial markets and developed an [[investment]] theory based on this principle. − − George Soros used the word reflexivity, to describe feedback in the financial markets and developed an investment theory based on this principle. − − 乔治•索罗斯(George Soros)用“反身性”(reflexivity)一词来描述金融市场的反馈，并根据这一原则发展了一套投资理论。 − − − − − − The conventional [[economic equilibrium]] model of [[supply and demand]] supports only ideal linear negative feedback and was heavily criticized by [[Paul Ormerod]] in his book ''[[The Death of Economics]]'', which, in turn, was criticized by traditional economists. This book was part of a change of perspective as economists started to recognise that [[chaos theory]] applied to nonlinear feedback systems including financial markets. − − The conventional economic equilibrium model of supply and demand supports only ideal linear negative feedback and was heavily criticized by Paul Ormerod in his book The Death of Economics, which, in turn, was criticized by traditional economists. This book was part of a change of perspective as economists started to recognise that chaos theory applied to nonlinear feedback systems including financial markets. − − 传统的经济均衡 / 需求模型只支持理想的线性负反馈，Paul Ormerod 在他的《经济学之死》一书中对此进行了严厉的批评，而这反过来又受到了传统经济学家的批评。随着经济学家开始认识到混沌理论适用于包括金融市场在内的非线性反馈系统，这本书是观点转变的一部分。 − − − − − − ==See also== − − ==See also== − − 参见 − − {{cmn| − − {{cmn| − − {{ cmn | − − * {{annotated link|Audio feedback}} − − − − * {{annotated link|Black box}} (see "experiment model") − − − − * {{annotated link|Cybernetics}} − − − − * {{annotated link|Feed forward (control)|Feed forward}} − − − − * {{annotated link|Interaction}} − − − − * {{annotated link|Low-key feedback}} − − − − * {{annotated link|Video feedback|Optical feedback}} − − − − * {{annotated link|Perverse incentive}} − − − − * {{annotated link|Recursion}} − − − − * {{annotated link|Resonance}} − − − − * {{annotated link|Stability criterion}} − − − − * {{annotated link|Strange loop}} − − − − * {{annotated link|Tactile}} − − − − * {{annotated link|Unintended consequences}} − − − − }} − − }} − − }} − − − − − − ==References== − − ==References== − − 参考资料 − − {{Reflist|30em}} − − − − − − − − ==Further reading== − − ==Further reading== − − 进一步阅读 − − * Katie Salen and [[Eric Zimmerman]]. ''Rules of Play''. [[MIT Press]]. 2004. {{ISBN|0-262-24045-9}}. Chapter 18: Games as Cybernetic Systems. − − − − *[[Andrey Korotayev|Korotayev A.]], Malkov A., Khaltourina D. [https://www.academia.edu/22215616/Introduction_to_Social_Macrodynamics_Secular_Cycles_and_Millennial_Trends ''Introduction to Social Macrodynamics: Secular Cycles and Millennial Trends.''] Moscow: URSS, 2006. {{ISBN|5-484-00559-0}} − − − − * Dijk, E., Cremer, D.D., Mulder, L.B., and Stouten, J. "How Do We React to Feedback in Social Dilemmas?" In Biel, Eek, Garling & Gustafsson, (eds.), ''New Issues and Paradigms in Research on Social Dilemmas'', New York: Springer, 2008. − − − − − − − − ==External links== − − ==External links== − − 外部链接 − − {{Wiktionary}} − − − − *{{Commons category-inline}} − − − − − − − − {{Complex systems topics}} − − − − − − − − [[Category:Control theory]] 第1,827行：
第325行： − [[Category:Electronic feedback| ]] − − − − [[Category:Feedback| ]] −
Moved page from wikipedia:en:Feedback (history)
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{{Other uses}}
{{Other uses}}
{{short description|Process where information about current status is used to influence future status}}
{{Use dmy dates|date=September 2020}}
{{Use dmy dates|date=July 2012}}
{{Complex systems}}[[File:General Feedback Loop.svg|thumb|A feedback loop where all outputs of a process are available as causal inputs to that process]]
{{Complex systems}}[[File:General Feedback Loop.svg|thumb|A feedback loop where all outputs of a process are available as causal inputs to that process]]
一种反馈回路，其中一个过程的所有输出都可作为该过程的因果输入
一种反馈回路，其中一个过程的所有输出都可作为该过程的因果输入
'''Feedback''' occurs when outputs of a system are routed back as inputs as part of a [[Signal chain (signal processing chain)|chain]] of [[Causality|cause-and-effect]] that forms a circuit or loop.<ref name=Ford>{{cite book |title=Modeling the Environment |author=Andrew Ford |chapter=Chapter 9: Information feedback and causal loop diagrams |pages=99 ''ff'' |publisher=Island Press |year=2010 |isbn=9781610914253 |chapter-url=https://books.google.com/books?id=38PJahZTzC0C&pg=PA99lpg=PA99 |quote=This chapter describes [[causal loop diagram]]s to portray the information feedback at work in a system. The word ''causal'' refers to cause-and-effect relationships. The word''loop'' refers to a closed chain of cause and effect that creates the feedback.}}</ref> The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems:
'''Feedback''' occurs when outputs of a system are routed back as inputs as part of a [[Signal chain (signal processing chain)|chain]] of [[Causality|cause-and-effect]] that forms a circuit or loop.<ref name=Ford>{{cite book |title=Modeling the Environment |author=Andrew Ford |chapter=Chapter 9: Information feedback and causal loop diagrams |pages=99 ''ff'' |publisher=Island Press |year=2010 |isbn=9781610914253 |chapter-url=https://books.google.com/books?id=38PJahZTzC0C&pg=PA99lpg=PA99 |quote=This chapter describes [[causal loop diagram]]s to portray the information feedback at work in a system. The word ''causal'' refers to cause-and-effect relationships. The word''loop'' refers to a closed chain of cause and effect that creates the feedback.}}</ref> The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems:
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to feed back into itself. The notion of cause-and-effect has to be handled carefully when applied to feedback systems:
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop.
当系统的输出作为输入路由回来，作为形成电路或回路的因果链的一部分时，反馈就发生了。
{{quote
{{quote
Centrifugal governors were used to regulate the distance and pressure between millstones in windmills since the 17th century. In 1788, James Watt designed his first centrifugal governor following a suggestion from his business partner Matthew Boulton, for use in the steam engines of their production. Early steam engines employed a purely reciprocating motion, and were used for pumping water – an application that could tolerate variations in the working speed, but the use of steam engines for other applications called for more precise control of the speed.
自17世纪以来，离心调速器就被用来调节风车磨盘之间的距离和压力。1788年，James Watt 根据他的商业伙伴 Matthew Boulton 的建议设计了他的第一台离心式调速器，用于他们生产的蒸汽机。早期的蒸汽机采用纯往复运动，用于抽水——这种应用可以容忍工作速度的变化，但是蒸汽机用于其他应用需要更精确的速度控制。
|text=Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole.
|text=Simple causal reasoning about a feedback system is difficult because the first system influences the second and second system influences the first, leading to a circular argument. This makes reasoning based upon cause and effect tricky, and it is necessary to analyze the system as a whole.
|author=Karl Johan Åström and Richard M.Murray
|author=Karl Johan Åström and Richard M.Murray
In 1868, James Clerk Maxwell wrote a famous paper, "On governors", that is widely considered a classic in feedback control theory.
1868年，詹姆斯·克拉克·麦克斯韦写了一篇著名的论文，《论州长》 ，这被广泛认为是反馈控制理论的经典之作。
| 题目反馈系统: 科学家和工程师介绍参考在线版本[ http://authors.library.caltech.edu/25062/1/feedback08.pdf 在这里]。
|title=''Feedback Systems: An Introduction for Scientists and Engineers''<ref>{{cite book |title=Feedback Systems: An Introduction for Scientists and Engineers |author1=Karl Johan Åström |author2=Richard M. Murray |chapter=§1.1: What is feedback? |chapter-url=https://books.google.com/books?id=cdG9fNqTDS8C&pg=PA1&dq=%22This+makes+reasoning+based+on+cause+and+effect+tricky%22 |isbn= 9781400828739 |year=2008 |page=1 |publisher=Princeton University Press}} Online version found [http://authors.library.caltech.edu/25062/1/Feedback08.pdf here].
</ref>}}
</ref>}}
Over the years there has been some dispute as to the best definition of feedback. According to Ashby (1956), mathematicians and theorists interested in the principles of feedback mechanisms prefer the definition of "circularity of action", which keeps the theory simple and consistent. For those with more practical aims, feedback should be a deliberate effect via some more tangible connection.
多年来，关于反馈的最佳定义一直存在一些争议。按照阿什比(1956)的说法，对反馈机制原理感兴趣的数学家和理论家更喜欢“循环行动”的定义，这使得理论简单和一致。对于那些有更实际目标的人来说，反馈应该是通过一些更切实的联系而产生的有意的效果。
==History==
==History==
Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter [[Economics|economic theory]] in Britain by the 18th century, but it was not at that time recognized as a universal abstraction and so did not have a name.<ref name=mayr>
Self-regulating mechanisms have existed since antiquity, and the idea of feedback had started to enter economic theory in Britain by the eighteenth century, but it was not at that time recognized as a universal abstraction and so did not have a name.<ref name=mayr>
Even prior to the terms being applied, James Clerk Maxwell had described several kinds of "component motions" associated with the centrifugal governors used in steam engines, distinguishing between those that lead to a continual increase in a disturbance or the amplitude of an oscillation, and those that lead to a decrease of the same.
甚至在这些术语被使用之前，詹姆斯·克拉克·麦克斯韦就已经描述了几种与蒸汽发动机中使用的离心调速器相关的“组件运动” ，区分那些导致扰动持续增加或振幅振荡的组件运动，以及那些导致扰动减少的组件运动。
{{Cite book |author= Otto Mayr|title=Authority, liberty, & automatic machinery in early modern Europe |year=1989 |isbn=978-0-8018-3939-9 | publisher=Johns Hopkins University Press |author-link=Otto Mayr }}</ref>
{{Cite book |author= Otto Mayr|title=Authority, liberty, & automatic machinery in early modern Europe |year=1989 |isbn=978-0-8018-3939-9 | publisher=Johns Hopkins University Press |author-link=Otto Mayr }}</ref>
the valence of the action or effect that alters the gap, based on whether it has a happy (positive) or unhappy (negative) emotional connotation to the recipient or observer.}}
改变差距的行为或效果的效价，基于它是否对接受者或观察者有快乐(积极)或不快乐(消极)的情感内涵。}
The first ever known artificial feedback device was a [[Ballcock|float valve]], for maintaining water at a constant level, invented in 270 BC in [[Alexandria]], [[Ancient Egypt|Egypt]].<ref name=":0">{{Cite book|title=Designing Kinetics for Architectural Facades|last=Moloney|first=Jules|publisher=Routledge|year=2011|isbn=978-0415610346}}</ref> This device illustrated the principle of feedback: a low water level opens the valve, the rising water then provides feedback into the system, closing the valve when the required level is reached. This then reoccurs in a circular fashion as the water level fluctuates.<ref name=":0" />
In general, feedback systems can have many signals fed back and the feedback loop frequently contain mixtures of positive and negative feedback where positive and negative feedback can dominate at different frequencies or different points in the state space of a system.
一般来说，反馈系统可以有多个信号反馈，反馈回路常常包含正反馈和负反馈的混合，其中正反馈和负反馈可以在系统的不同频率或状态空间的不同点占主导地位。
[[Centrifugal governor]]s were used to regulate the distance and pressure between [[millstone]]s in [[windmill]]s since the 17th century. In 1788, [[James Watt]] designed his first centrifugal governor following a suggestion from his business partner [[Matthew Boulton]], for use in the [[steam engine]]s of their production. Early steam engines employed a purely [[reciprocating motion]], and were used for pumping water – an application that could tolerate variations in the working speed, but the use of steam engines for other applications called for more precise control of the speed.
The term bipolar feedback has been coined to refer to biological systems where positive and negative feedback systems can interact, the output of one affecting the input of another, and vice versa.
双极反馈一词被创造出来，指的是生物系统中正反馈系统可以相互作用，一个系统的输出影响另一个系统的输入，反之亦然。
In [[1868]], [[James Clerk Maxwell]] wrote a famous paper, "On governors", that is widely considered a classic in feedback control theory.<ref>{{cite journal|last=Maxwell|first=James Clerk|title=On Governors|journal=Proceedings of the Royal Society of London|volume= 16|year= 1868 |pages= 270–283 | doi = 10.1098/rspl.1867.0055 | jstor=112510|doi-access=free}}</ref> This was a landmark paper on [[control theory]] and the mathematics of feedback.
The Great Eastern was one of the largest steamships of its time and employed a steam powered rudder with feedback mechanism designed in 1866 by John McFarlane Gray. Joseph Farcot coined the word servo in 1873 to describe steam-powered steering systems. Hydraulic servos were later used to position guns. Elmer Ambrose Sperry of the Sperry Corporation designed the first autopilot in 1912. Nicolas Minorsky published a theoretical analysis of automatic ship steering in 1922 and described the PID controller.
大东方号是当时最大的轮船之一，它使用了一个带有反馈机制的蒸汽动力舵，由约翰 · 麦克法兰 · 格雷在1866年设计。约瑟夫 · 法科特在1873年创造了“伺服”这个词来描述蒸汽动力转向系统。液压伺服系统后来被用来定位枪支。史派里公司的 Elmer Ambrose Sperry 在1912年设计了第一个自动驾驶仪。尼古拉斯·米诺尔斯基在1922年发表了一篇关于船舶自动操舵的理论分析，并描述了 PID 控制器。
The verb phrase ''to feed back'', in the sense of returning to an earlier position in a mechanical process, was in use in the US by the 1860s,<ref>
The verb phrase "to feed back", in the sense of ''returning to an earlier position'' in a mechanical process, was in use in the US by the 1860s,<ref>
''"Heretofore ... it has been necessary to reverse the motion of the rollers, thus causing the material to travel or feed back, ..."''
''"Heretofore ... it has been necessary to reverse the motion of the rollers, thus causing the material to travel or feed back, ..."''
Oscillators are often characterized by the frequency of their output signal:
振荡器的频率通常与其输出信号的频率成拥有属性:
HH Cole, "Improvement in Fluting-Machines", [http://www.google.co.nz/patents/US55469 US Patent 55,469 (1866)] accessed 23 March 2012.
</ref><ref>
</ref><ref>
''"When the journal or spindle is cut ... and the carriage is about to feed back by a change of the sectional nut or burr upon the screw-shafts, the operator seizes the handle..."'' JM Jay, "Improvement in Machines for Making the Spindles of Wagon-Axles", [http://www.google.co.nz/patents/US47769 US Patent 47,769 (1865)] accessed 23 March 2012.
''"When the journal or spindle is cut ... and the carriage is about to feed back by a change of the sectional nut or burr upon the screw-shafts, the operator seizes the handle..."'' JM Jay, "Improvement in Machines for Making the Spindles of Wagon-Axles", [http://www.google.co.nz/patents/US47769 US Patent 47,769 (1865)] accessed 23 Mar 2012.
[http://www.cdvandtext2.org/Braun-Nobel-lecture%201909.pdf]
</ref> and in 1909, Nobel laureate [[Karl Ferdinand Braun]] used the term "feed-back" as a noun to refer to (undesired) [[Coupling (electronics)|coupling]] between components of an [[electronic circuit]].<ref>''"...as far as possible the circuit has no feed-back into the system being investigated."''
[http://www.cdvandtext2.org/Braun-Nobel-lecture%201909.pdf]
[http://www.cdvandtext2.org/Braun-Nobel-lecture%201909.pdf]
Karl Ferdinand Braun, [https://www.nobelprize.org/nobel_prizes/physics/laureates/1909/braun-lecture.html "Electrical oscillations and wireless telegraphy"], Nobel Lecture, 11 December 1909. Retrieved 19 March 2012.</ref>
Karl Ferdinand Braun, [https://www.nobelprize.org/nobel_prizes/physics/laureates/1909/braun-lecture.html "Electrical oscillations and wireless telegraphy"], Nobel Lecture, 11 December 1909. Retrieved 19 Mar 2012.</ref>
Oscillators designed to produce a high-power AC output from a DC supply are usually called inverters.
为从直流电源产生大功率交流输出而设计的振荡器通常称为逆变器。
By the end of 1912, researchers using early electronic amplifiers ([[audion tube|audions]]) had discovered that deliberately coupling part of the output signal back to the input circuit would boost the amplification (through [[Regenerative circuit|regeneration]]), but would also cause the audion to howl or sing.<ref name="bennett">{{Cite book|url=http://worldcat.org/isbn/0-906-04807-9|title=A history of control engineering, 1800–1930|author=Stuart Bennett|publisher=Peregrinus for the Institution of Electrical Engineers|year=1979|isbn=978-0-906048-07-8|location=Stevenage; New York}}
By the end of 1912, researchers using early electronic amplifiers ([[audion tube|audions]]) had discovered that deliberately coupling part of the output signal back to the input circuit would boost the amplification (through [[Regenerative circuit|regeneration]]), but would also cause the audion to howl or sing.<ref name="bennett">{{Cite book|url=http://worldcat.org/isbn/0-906-04807-9|title=A history of control engineering, 1800–1930|author=Stuart Bennett|publisher=Peregrinus for the Institution of Electrical Engineers|year=1979|isbn=978-0-906048-07-8|location=Stevenage; New York}}
There are two main types of electronic oscillator: the linear or harmonic oscillator and the nonlinear or relaxation oscillator.
振盪器有两种主要类型: 线性的或谐振子的和非线性的或张弛振荡器的。
[https://books.google.com/books?id=1gfKkqB_fTcC]
[https://books.google.com/books?id=1gfKkqB_fTcC]
</ref> This action of feeding back of the signal from output to input gave rise to the use of the term "feedback" as a distinct word by 1920.<ref name=bennett/>
</ref> This action of feeding back of the signal from output to input gave rise to the use of the term "feedback" as a distinct word by 1920.<ref name=bennett/>
A 4-bit [[ring counter using D-type flip flops]]
4位[使用 d 型触发器的环形计数器]
Over the years there has been some dispute as to the best definition of feedback. According to [[William Ross Ashby|Ashby]] (1956), mathematicians and theorists interested in the ''principles'' of feedback mechanisms prefer the definition of ''circularity of action'', which keeps the theory simple and consistent. For those with more ''practical'' aims, feedback should be a deliberate effect via some more tangible connection.
Over the years there has been some dispute as to the best definition of feedback. According to [[William Ross Ashby|Ashby]] (1956), mathematicians and theorists interested in the principles of feedback mechanisms prefer the definition of "circularity of action", which keeps the theory simple and consistent. For those with more practical aims, feedback should be a deliberate effect via some more tangible connection.
{{Quote|[Practical experimenters] object to the mathematician's definition, pointing out that this would force them to say that feedback was present in the ordinary pendulum ... between its position and its momentum—a "feedback" that, from the practical point of view, is somewhat mystical. To this the mathematician retorts that if feedback is to be considered present only when there is an actual wire or nerve to represent it, then the theory becomes chaotic and riddled with irrelevancies.<ref name=Ashby>
{{Quote|[Practical experimenters] object to the mathematician's definition, pointing out that this would force them to say that feedback was present in the ordinary pendulum ... between its position and its momentum—a "feedback" that, from the practical point of view, is somewhat mystical. To this the mathematician retorts that if feedback is to be considered present only when there is an actual wire or nerve to represent it, then the theory becomes chaotic and riddled with irrelevancies.<ref name=Ashby>
A latch or a flip-flop is a circuit that has two stable states and can be used to store state information. They typically constructed using feedback that crosses over between two arms of the circuit, to provide the circuit with a state. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in sequential logic. Latches and flip-flops are fundamental building blocks of digital electronics systems used in computers, communications, and many other types of systems.
锁存器或触发器是具有两个稳定状态的电路，可用于存储状态信息。它们通常利用电路的两个臂之间交叉的反馈来构造，以便为电路提供一个状态。该电路可以通过施加到一个或多个控制输入的信号来改变状态，并且具有一个或两个输出。它是时序逻辑电路的基本存储元素。锁存器和触发器是用于计算机、通信和许多其他类型系统的数字电子系统的基本构件。
{{cite book |author=W. Ross Ashby |title=An introduction to cybernetics |publisher=Chapman & Hall |year=1957 |url=http://pcp.vub.ac.be/books/IntroCyb.pdf}}</ref>{{rp|page=54}}}}
{{cite book |author=W. Ross Ashby |title=An introduction to cybernetics |publisher=Chapman & Hall |year=1957 |url=http://pcp.vub.ac.be/books/IntroCyb.pdf}}</ref>{{rp|page=54}}}}
Latches and flip-flops are used as data storage elements. Such data storage can be used for storage of state, and such a circuit is described as sequential logic. When used in a finite-state machine, the output and next state depend not only on its current input, but also on its current state (and hence, previous inputs). It can also be used for counting of pulses, and for synchronizing variably-timed input signals to some reference timing signal.
锁存器和触发器用作数据存储元件。这样的数据存储可以用来存储状态，这样的电路被描述为时序逻辑电路。当用于有限状态机时，输出和下一状态不仅取决于其当前输入，还取决于其当前状态(因此，以前的输入)。它也可以用于计数脉冲，并用于同步一些参考定时信号的变时输入信号。
Focusing on uses in management theory, Ramaprasad (1983) defines feedback generally as "...information about the gap between the actual level and the reference level of a system parameter" that is used to "alter the gap in some way". He emphasizes that the information by itself is not feedback unless translated into action.<ref name="Ramaprasad">{{Cite journal | doi=10.1002/bs.3830280103|title = On the definition of feedback| journal=Behavioral Science| volume=28| pages=4–13|year = 1983|last1 = Ramaprasad|first1 = Arkalgud}}</ref>
Focusing on uses in management theory, Ramaprasad (1983) defines feedback generally as "...information about the gap between the actual level and the reference level of a system parameter" that is used to "alter the gap in some way". He emphasizes that the information by itself is not feedback unless translated into action.<ref name="Ramaprasad">{{Cite journal | doi=10.1002/bs.3830280103|title = On the definition of feedback| journal=Behavioral Science| volume=28| pages=4–13|year = 1983|last1 = Ramaprasad|first1 = Arkalgud}}</ref>
Flip-flops can be either simple (transparent or opaque) or clocked (synchronous or edge-triggered). Although the term flip-flop has historically referred generically to both simple and clocked circuits, in modern usage it is common to reserve the term flip-flop exclusively for discussing clocked circuits; the simple ones are commonly called latches.
触发器可以是简单的(透明的或者不透明的)或者是计时的(同步的或者边缘触发的)。虽然触发器这个术语在历史上一直泛指简单电路和时钟电路，但在现代用法中，通常将触发器这个术语专门用于讨论时钟电路，简单的电路通常称为锁存电路。
==Types==
==Types==
Using this terminology, a latch is level-sensitive, whereas a flip-flop is edge-sensitive. That is, when a latch is enabled it becomes transparent, while a flip flop's output only changes on a single type (positive going or negative going) of clock edge.
使用这个术语，锁存器是电平敏感的，而触发器是边缘敏感的。也就是说，当锁存器启用时，它变得透明，而触发器的输出只在时钟边缘的单一类型(正向或负向)上发生变化。
===Positive and negative feedback===
===Positive and negative feedback===
{{Main|Negative feedback|Positive feedback}}
{{Main|Negative feedback|Positive feedback}}
[[File:Set-point control.png|thumb|350px|Maintaining a desired system performance despite disturbance using negative feedback to reduce system error]]
[[File:Set-point control.png|thumb|350px|Maintaining a desired system performance despite disturbance using negative feedback to reduce system error]]
Feedback loops provide generic mechanisms for controlling the running, maintenance, and evolution of software and computing systems. Feedback-loops are important models in the engineering of adaptive software, as they define the behaviour of the interactions among the control elements over the adaptation process, to guarantee system properties at run-time. Feedback loops and foundations of control theory have been successfully applied to computing systems. In particular, they have been applied to the development of products such as IBM's Universal Database server and IBM Tivoli. From a software perspective, the autonomic (MAPE, monitor analyze plan execute) loop proposed by researchers of IBM is another valuable contribution to the application of feedback loops to the control of dynamic properties and the design and evolution of autonomic software systems.
反馈回路为控制软件和计算系统的运行、维护和进化提供了通用机制。反馈回路是自适应软件工程中的重要模型，它定义了自适应过程中控制元件之间相互作用的行为，以保证系统在运行时的性能。反馈环路和控制理论的基础已成功地应用于计算系统。特别是，它们已经应用于产品的开发，如 IBM 的 Universal Database server 和 IBM Tivoli。从软件的角度来看，IBM 研究人员提出的自主(MAPE，monitor analyze plan execute)回路是对反馈回路应用于动态特性控制和自主软件系统设计与演化的另一个有价值的贡献。
[[File:Outcome Feedback Negative Feedback Loop.png|thumb|An example of a negative feedback loop with goals]]
[[File:Outcome Feedback Negative Feedback Loop.png|thumb|An example of a negative feedback loop with goals]]
[[File:Process Feedback Loop.png|thumb|A positive feedback loop example]]
[[File:Process Feedback Loop.png|thumb|A positive feedback loop example]]
Positive feedback: If the signal fed back from output is in phase with the input signal, the feedback is called positive feedback.
Positive feedback: If the signal fed back from output is in phase with the input signal,the feedback is called positive feedback.
Negative feedback: If the signal fed back is of opposite polarity or out of phase by 180° with respect to input signal, the feedback is called as negative feedback.
Negative feedback: If the signal fed back is of opposite polarity or out of phase by 180° with respect to input signal, the feedback is called as negative feedback.
As an example of negative feedback, the diagram might represent a [[cruise control]] system in a car, for example, that matches a target speed such as the speed limit. The controlled system is the car; its input includes the combined torque from the engine and from the changing slope of the road (the disturbance). The car's speed (status) is measured by a [[speedometer]]. The error signal is the departure of the speed as measured by the speedometer from the target speed (set point). This measured error is interpreted by the controller to adjust the accelerator, commanding the fuel flow to the engine (the effector). The resulting change in engine torque, the feedback, combines with the torque exerted by the changing road grade to reduce the error in speed, minimizing the road disturbance.
As an example of negative feedback, the diagram might represent a [[cruise control]] system in a car, for example, that matches a target speed such as the speed limit. The controlled system is the car; its input includes the combined torque from the engine and from the changing slope of the road (the disturbance). The car's speed (status) is measured by a [[speedometer]]. The error signal is the departure of the speed as measured by the speedometer from the target speed (set point). This measured error is interpreted by the controller to adjust the accelerator, commanding the fuel flow to the engine (the effector). The resulting change in engine torque, the feedback, combines with the torque exerted by the changing road grade to reduce the error in speed, minimizing the road disturbance.
Feedback is also a useful design principle for designing user interfaces.
反馈也是设计用户界面的一个有用的设计原则。
The terms "positive" and "negative" were first applied to feedback prior to WWII. The idea of positive feedback was already current in the 1920s with the introduction of the [[regenerative circuit]].<ref name=mindell>
The terms "positive" and "negative" were first applied to feedback prior to WWII. The idea of positive feedback was already current in the 1920s with the introduction of the [[regenerative circuit]].<ref name=mindell>
{{Cite book
{{Cite book
|author=David A. Mindell
|author=David A. Mindell
Video feedback is the video equivalent of acoustic feedback. It involves a loop between a video camera input and a video output, e.g., a television screen or monitor. Aiming the camera at the display produces a complex video image based on the feedback.
视频反馈是视频等效的声学反馈。它涉及一个循环之间的视频摄像机输入和视频输出，例如，一个电视屏幕或显示器。将摄像机对准显示器，根据反馈信息生成复杂的视频图像。
|title=Between Human and Machine : Feedback, Control, and Computing before Cybernetics.
|title=Between Human and Machine : Feedback, Control, and Computing before Cybernetics.
|year= 2002
|year= 2002
|publisher=Johns Hopkins University Press
|publisher=Johns Hopkins University Press
|location=Baltimore, MD, US
|location=Baltimore, MD, US
|url=https://books.google.com/books?id=sExvSbe9MSsC|isbn=9780801868955
|url=https://books.google.com/books?id=sExvSbe9MSsC|isbn=9780801868955
}}
}}
</ref> Friis and Jensen (1924) described regeneration in a set of electronic amplifiers as a case where ''the "feed-back" action is positive'' in contrast to negative feed-back action, which they mention only in passing.<ref name=friis>
</ref> Friis and Jensen (1924) described regeneration in a set of electronic amplifiers as a case where ''the "feed-back" action is positive'' in contrast to negative feed-back action, which they mention only in passing.<ref name=friis>
The stock market is an example of a system prone to oscillatory "hunting", governed by positive and negative feedback resulting from cognitive and emotional factors among market participants. For example:
股票市场就是这样一个系统的例子，它倾向于振荡性的”捕猎” ，由市场参与者的认知和情感因素所产生的正反馈和负反馈来控制。例如:
Friis, H.T., and A.G.Jensen. "High Frequency Amplifiers" Bell System Technical Journal 3 (April 1924):181–205.</ref> [[Harold Stephen Black]]'s classic 1934 paper first details the use of negative feedback in electronic amplifiers. According to Black:
Friis, H.T., and A.G.Jensen. "High Frequency Amplifiers" Bell System Technical Journal 3 (April 1924):181–205.</ref> [[Harold Stephen Black]]'s classic 1934 paper first details the use of negative feedback in electronic amplifiers. According to Black:
{{Quote|Positive feed-back increases the gain of the amplifier, negative feed-back reduces it.<ref name=black>
{{Quote|Positive feed-back increases the gain of the amplifier, negative feed-back reduces it.<ref name=black>
H.S. Black, "Stabilized feed-back amplifiers", ''Electrical Engineering'', vol. 53, pp. 114–120, January 1934.</ref>}}
H.S. Black, "Stabilized feed-back amplifiers", ''Electrical Engineering'', vol. 53, pp. 114–120, January 1934.</ref>}}
According to Mindell (2002) confusion in the terms arose shortly after this:
According to Mindell (2002) confusion in the terms arose shortly after this:
George Soros used the word reflexivity, to describe feedback in the financial markets and developed an investment theory based on this principle.
乔治•索罗斯(George Soros)用“反身性”(reflexivity)一词来描述金融市场的反馈，并根据这一原则发展了一套投资理论。
{{Quote|...Friis and Jensen had made the same distinction Black used between "positive feed-back" and "negative feed-back", based not on the sign of the feedback itself but rather on its effect on the amplifier's gain. In contrast, Nyquist and Bode, when they built on Black's work, referred to negative feedback as that with the sign reversed. Black had trouble convincing others of the utility of his invention in part because confusion existed over basic matters of definition.<ref name=mindell/>{{rp|page=121}}}}
{{Quote|...Friis and Jensen had made the same distinction Black used between "positive feed-back" and "negative feed-back", based not on the sign of the feedback itself but rather on its effect on the amplifier's gain. In contrast, Nyquist and Bode, when they built on Black's work, referred to negative feedback as that with the sign reversed. Black had trouble convincing others of the utility of his invention in part because confusion existed over basic matters of definition.<ref name=mindell/>{{rp|page=121}}}}
The conventional economic equilibrium model of supply and demand supports only ideal linear negative feedback and was heavily criticized by Paul Ormerod in his book The Death of Economics, which, in turn, was criticized by traditional economists. This book was part of a change of perspective as economists started to recognise that chaos theory applied to nonlinear feedback systems including financial markets.
传统的经济均衡/需求模型只支持理想的线性负反馈，Paul Ormerod 在他的《经济学之死》一书中对此进行了严厉的批评，而这本书反过来又遭到了传统经济学家的批评。随着经济学家开始认识到混沌理论适用于包括金融市场在内的非线性反馈系统，这本书是观点转变的一部分。
Even prior to the terms being applied, [[James Clerk Maxwell]] had described several kinds of "component motions" associated with the [[centrifugal governor]]s used in steam engines, distinguishing between those that lead to a continual ''increase'' in a disturbance or the amplitude of an oscillation, and those that lead to a ''decrease'' of the same.<ref name=maxwell>{{cite journal|last=Maxwell|first=James Clerk|title=On Governors|url=http://en.wikipedia.org/wiki/File:On_Governors.pdf|journal=Proceedings of the Royal Society of London|volume= 16|year= 1868 |pages= 270–283|doi=10.1098/rspl.1867.0055}}</ref>
Even prior to the terms being applied, [[James Clerk Maxwell]] had described several kinds of "component motions" associated with the [[centrifugal governor]]s used in steam engines, distinguishing between those that lead to a continual ''increase'' in a disturbance or the amplitude of an oscillation, and those that lead to a ''decrease'' of the same.<ref name=maxwell>
{{cite journal|last=Maxwell|first=James Clerk|title=On Governors|url=http://en.wikipedia.org/wiki/File:On_Governors.pdf|journal=Proceedings of the Royal Society of London|volume= 16|year= 1868 |pages= 270–283|doi=10.1098/rspl.1867.0055}}</ref>
====Terminology====
====Terminology====
{{cmn|
{{ cmn |
The terms positive and negative feedback are defined in different ways within different disciplines.
The terms positive and negative feedback are defined in different ways within different disciplines.
# the altering of the ''gap'' between reference and actual values of a parameter, based on whether the gap is ''widening'' (positive) or ''narrowing'' (negative).<ref name="Ramaprasad" />
# the altering of the ''gap'' between reference and actual values of a parameter, based on whether the gap is ''widening'' (positive) or ''narrowing'' (negative).<ref name="Ramaprasad" />
# the [[Valence (psychology)|valence]] of the ''action'' or ''effect'' that alters the gap, based on whether it has a ''happy'' (positive) or ''unhappy'' (negative) emotional connotation to the recipient or observer.<ref name=herold1977>Herold, David M., and Martin M. Greller. "Research Notes. FEEDBACK THE DEFINITION OF A CONSTRUCT." Academy of management Journal 20.1 (1977): 142-147.</ref>
# the [[Valence (psychology)|valence]] of the ''action'' or ''effect'' that alters the gap, based on whether it has a ''happy'' (positive) or ''unhappy'' (negative) emotional connotation to the recipient or observer.<ref name=herold1977>Herold, David M., and Martin M. Greller. "Research Notes. FEEDBACK THE DEFINITION OF A CONSTRUCT." Academy of management Journal 20.1 (1977): 142-147.</ref>
The two definitions may cause confusion, such as when an incentive (reward) is used to boost poor performance (narrow a gap). Referring to definition 1, some authors use alternative terms, replacing ''positive/negative'' with ''self-reinforcing/self-correcting'',<ref name="senge">
The two definitions may cause confusion, such as when an incentive (reward) is used to boost poor performance (narrow a gap). Referring to definition 1, some authors use alternative terms, replacing ''positive/negative'' with ''self-reinforcing/self-correcting'',<ref name="senge">
{{Cite book
{{Cite book
|author=Peter M. Senge
|author=Peter M. Senge
|title=The Fifth Discipline: The Art and Practice of the Learning Organization
|title=The Fifth Discipline: The Art and Practice of the Learning Organization
|year=1990
|year=1990
|publisher=Doubleday
|publisher=Doubleday
|location=New York
|location=New York
|isbn=978-0-385-26094-7
|isbn=978-0-385-26094-7
|page=424
|page=424
|url=https://archive.org/details/fifthdisciplineasen00seng
|url=https://archive.org/details/fifthdisciplineasen00seng
}}
}}
</ref> ''reinforcing/balancing'',<ref name="sterman">
</ref> ''reinforcing/balancing'',<ref name="sterman">
John D. Sterman, ''Business Dynamics: Systems Thinking and Modeling for a Complex World'', McGraw Hill/Irwin, 2000. {{ISBN|978-0-07-238915-9}}
John D. Sterman, ''Business Dynamics: Systems Thinking and Modeling for a Complex World'', McGraw Hill/Irwin, 2000. {{ISBN|978-0-07-238915-9}}
</ref> ''discrepancy-enhancing/discrepancy-reducing''<ref name="carver">
</ref> ''discrepancy-enhancing/discrepancy-reducing''<ref name="carver">
Charles S. Carver, Michael F. Scheier: ''On the Self-Regulation of Behavior'' Cambridge University Press, 2001
Charles S. Carver, Michael F. Scheier: ''On the Self-Regulation of Behavior'' Cambridge University Press, 2001
</ref> or ''regenerative/degenerative''<ref>
</ref> or ''regenerative/degenerative''<ref>
Hermann A Haus and Richard B. Adler, ''Circuit Theory of Linear Noisy Networks'', MIT Press, 1959
Hermann A Haus and Richard B. Adler, ''Circuit Theory of Linear Noisy Networks'', MIT Press, 1959
</ref> respectively. And for definition 2, some authors advocate describing the action or effect as positive/negative ''[[Reinforcement#Reinforcement|reinforcement]]'' or ''[[Reinforcement#Punishment|punishment]]'' rather than feedback.<ref name="Ramaprasad" /><ref name="skinner">
</ref> respectively. And for definition 2, some authors advocate describing the action or effect as positive/negative ''[[Reinforcement#Reinforcement|reinforcement]]'' or ''[[Reinforcement#Punishment|punishment]]'' rather than feedback.<ref name="Ramaprasad" /><ref name="skinner">
BF Skinner, ''The Experimental Analysis of Behavior'', American Scientist, Vol. 45, No. 4 (SEPTEMBER 1957), pp. 343-371</ref>
BF Skinner, ''The Experimental Analysis of Behavior'', American Scientist, Vol. 45, No. 4 (SEPTEMBER 1957), pp. 343-371</ref>
Yet even within a single discipline an example of feedback can be called either positive or negative, depending on how values are measured or referenced.<ref>
Yet even within a single discipline an example of feedback can be called either positive or negative, depending on how values are measured or referenced.<ref>
"However, after scrutinizing the statistical properties of the structural equations, the members of the committee assured themselves that it is possible to have a significant positive feedback loop when using standardized scores, and a negative loop when using real scores."
"However, after scrutinizing the statistical properties of the structural equations, the members of the committee assured themselves that it is possible to have a significant positive feedback loop when using standardized scores, and a negative loop when using real scores."
Ralph L. Levine, Hiram E. Fitzgerald. ''Analysis of the dynamic psychological systems: methods and applications'', {{ISBN|978-0306437465}} (1992) page 123</ref>
Ralph L. Levine, Hiram E. Fitzgerald. ''Analysis of the dynamic psychological systems: methods and applications'', {{ISBN|978-0306437465}} (1992) page 123</ref>
This confusion may arise because feedback can be used for either ''informational'' or ''motivational'' purposes, and often has both a ''[[Qualitative property|qualitative]]'' and a ''[[Quantitative property|quantitative]]'' component. As Connellan and Zemke (1993) put it:
This confusion may arise because feedback can be used for either ''informational'' or ''motivational'' purposes, and often has both a ''[[Qualitative property|qualitative]]'' and a ''[[Quantitative property|quantitative]]'' component. As Connellan and Zemke (1993) put it:
{{Quote|''Quantitative'' feedback tells us how much and how many. ''Qualitative'' feedback tells us how good, bad or indifferent.<ref name=Connellan>Thomas K. Connellan and Ron Zemke, "Sustaining Knock Your Socks Off Service" AMACOM, 1 July 1993. {{ISBN|0-8144-7824-7}}</ref>{{rp|page=102}}}}
{{Quote|''Quantitative'' feedback tells us how much and how many. ''Qualitative'' feedback tells us how good, bad or indifferent.<ref name=Connellan>Thomas K. Connellan and Ron Zemke, "Sustaining Knock Your Socks Off Service" AMACOM, 1 July 1993. {{ISBN|0-8144-7824-7}}</ref>{{rp|page=102}}}}
====Limitations of negative and positive feedback====
====Limitations of negative and positive feedback====
While simple systems can sometimes be described as one or the other type, many systems with feedback loops cannot be so easily designated as simply positive or negative, and this is especially true when multiple loops are present.
While simple systems can sometimes be described as one or the other type, many systems with feedback loops cannot be so easily designated as simply positive or negative, and this is especially true when multiple loops are present.
Category:Control theory
Category:Control theory
范畴: 控制理论
范畴: 控制理论
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